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Abstract
Multiparous Israeli-Holstein cows (n=42) averaging 158 d in milk and 621 kg of body weight were used to investigate the effects of energy source (fat or concentrate) on production, rumination time, energy balance, metabolic heat production, and efficiency under hot and humid conditions. Cows were assigned to 3 diet treatment groups: a lactating-cow ration (1.75 Mcal of net energy for lactation/kg of dry matter (DM; control); supplemented with 0.825 kg/d per cow of ground corn grain (2.7% of diet; HG); or supplemented with 0.300 kg/d per cow of calcium salts of fatty acids (1.5% of diet; HF). Milk production, body weight, and rumination time were recorded daily. Rectal temperature and respiratory rate (RR) were measured weekly. Mean daily maximum ambient temperature, relative humidity, and temperature-humidity index were 31.5 degrees C, 86.6%, and 76.8, respectively. Dry matter intake was lower in HF and HG cows than in controls. Average daily rumination time was lowest in the HG group: 393.0, 377.7, and 390.8 min/d for control, HG, and HF cows, respectively. Milk production was higher in the control group than in the HG group; milk fat content was 0.38 units higher and fat yield was 11% greater in HF cows than in HG cows. Fat-corrected milk yield was higher in HF cows than in HG cows, but not higher than in controls. Energy balance in HF cows was lower than in both other groups, and nonesterified fatty acid concentrations in plasma were increased by fat supplementation. Rectal temperature was highest in HF cows, and RR was higher in the HF cows than in the controls. Metabolic heat production was similar in HG and HF cows and lower than in controls. Body weight gain of the HG cows tended to be higher than that of the others. Efficiency of conversion of DM or energy intake to milk and fat-corrected milk was higher in HF cows than in both other groups; however, when taking the energy retention in body mass into account, no differences in energy utilization were observed between HF and HG groups. A principal component analysis revealed that rumination time played a pivotal role in the deleterious effect of heat stress in dairy cows. In conclusion, increasing the energy density in diets of heat-stressed mid-lactation cows over 1.75 Mcal/kg of DM was not effective in enhancing production. Both dietary treatments were effective in reducing metabolic heat production, but the changes were not reflected in rectal temperature and RR. Fat supplementation increased metabolic efficiency; however, whereas HF cows prioritized milk production, HG cows channeled energy for body mass deposition.
... Lipid sources can be strategically fed to lactating cows raised in warm regions to replace carbohydrate sources, enabling manipulation of energy density in the diet while aiding in the control of heat stress [4,5]. Depending on the lipid composition of the supplement, these ingredients can also improve the FA profile of milk fat [6]. ...
... 4 Sum of odd-and branched-chain fatty acids, except for 13:0, iso 17:0, and anteiso 17:0, as these co-eluted with cis-9 12:1, trans-9 16:1, and cis-9 16:1, respectively. 5 Stearoyl-CoA desaturase-1 (SCD-1) indices calculated for cis-9 14:1/14:0 (SCD14), cis-9 16:1/16:0 (SCD16), cis-9 18:1/18:0 (SCD18), and cis-9, trans-11 CLA/trans-11 18:1 (SCDCLA) [17]. ...
... 3 Components: bicalcium phosphate, limestone, common salt, sulfur flower, zinc sulfate, copper sulfate, manganese sulfate, potassium iodate, and sodium selenite. 4 g/kg of fresh matter.5 Neutral detergent fiber corrected for ash and protein.6 ...
Simple Summary
Lipid supplementation is a common practice in dairy cow nutrition to control heat stress, provide more energy, and alter the fatty acid profile of milk fat. Full-fat corn germ (FFCG)—a by-product from corn processing—has been indicated as an alternative lipid ingredient because of its positive effects on milk production and milk fatty acid profile. Yet, FFCG may cause ruminal disturbances that lead to milk fat depression (MFD) in cows fed fresh sugarcane and cactus cladodes, which are important forage resources for the supplementation of dairy herds in the semi-arid region. Our most recent results show that replacing fresh sugarcane with sugarcane bagasse in the diet prevents the MFD observed in cows fed FFCG. The association of FFCG, cactus cladodes, and sugarcane bagasse improves milk production and milk fat content and alters the composition of milk fat towards a healthier fatty acid profile. Hence, FFCG supplementation may be advantageous to milk producers through improved cow performance while promoting greater fat yield and fat quality for the manufacturing of dairy products with potential health benefits.
Abstract
We evaluated the performance, milk composition, and milk fatty acid profile of cows fed diets composed of cactus cladodes (Opuntia stricta [Haw.] Haw), sugarcane bagasse and increasing levels of full-fat corn germ (FFCG). We hypothesized that ground corn can be effectively replaced by FFCG when cactus cladodes and sugarcane bagasse are used as forage sources. The cows were randomly distributed into two 5 × 5 Latin Squares and fed five diets in which ground corn was progressively replaced with full-fat corn germ (FFCG; 0%, 25%, 50%, 75%, or 100% of substitution). Adding FFCG to the diet increased milk production and milk fat content and reduced milk protein content. Overall, FFCG reduced the proportion of saturated FAs and increased mono- and polyunsaturated FAs in milk, including CLA isomers. In addition, activity indices of stearoyl-CoA desaturase were reduced by increasing levels of FFCG. We conclude that the substitution of corn for FFCG in diets based on cactus cladodes and sugarcane bagasse positively modifies the FA profile of milk and could add commercial value to milk products (e.g., CLA-enriched milk). In addition, the milk fat response indicates that the basal diet was favorable to the rumen environment, preventing the trans-10 shift commonly associated with milk fat depression.
... Cows receiving by-pass fat produced significantly more than 4% FCM and ECM per kilogram of total DMI and tended to produce more 4% FCM and ECM per Mcal of NEL intake ( Table 2). Similar results were obtained in previous studies [11] [13] [36] and are in agreement with [37] suggestion that increasing diet energy density by supplementation with non-fermentative nutrients might improve the conversion efficiency of feed to milk in heat-stressed cows. ...
... Apparently, in the cows of the SPF group, Open Journal of Animal Sciences the energy consumed was not directed to a differential accumulation of body reserves, but was diverted to the production of 4% FCM and ECM (Table 3). Similar results were obtained by [36] when replacing energy in the form of starch (corn grain) with energy in the form of lipids (calcium salts of fatty acids) in the diet of high-producing cows in mid-lactation and under heat stress conditions. ...
... Most of the experiments reviewed by [35] reported little or no difference in body temperatures and respiratory rates. In fact, only one report, in line with our results, indicated that cows fed additional fat had increased body temperatures and respiratory rates, even though the estimated metabolic heat production was lower compared with cows in the control group [36]. ...
... The change in maximum vaginal temperature from day R1 to R2 was not affected by either canola oil (p = 0.38) or betaine (p = 0.60). Neither canola oil nor betaine had any effect on the difference in vaginal temperature between day R7 and pre-challenge (p > 0. 38), and this small difference in vaginal temperature was not significantly different to zero (p > 0.16). ...
... Experiments using controlled-environment chambers to create a heat challenge also found greater milk yields in cows fed a diet supplemented with fat [36,37]. However, some studies report nil effect of dietary fat on milk production during hot weather [38]. This could be due to a number of reasons, such as the type of fat supplement [39], the severity and duration of heat exposure, and in the case of Moallem et al. [38], the use of cooling amenities five times per day. ...
... However, some studies report nil effect of dietary fat on milk production during hot weather [38]. This could be due to a number of reasons, such as the type of fat supplement [39], the severity and duration of heat exposure, and in the case of Moallem et al. [38], the use of cooling amenities five times per day. ...
Supplementing the diet of lactating cows with ingredients that increase energy density, or reduce internal heat production, may reduce some of the negative impacts of hot weather on milk yield. Thirty-two dairy cows were assigned either: (1) basal diet only, (2) basal diet plus canola oil, (3) basal diet plus betaine, or (4) basal diet plus canola oil and betaine. The basal diet was lucerne hay, pasture silage, and grain. Cows were exposed to a four-day heat challenge (temperature-humidity index 74 to 84) in controlled-environment chambers. Canola oil supplementation increased milk production (22.0 vs. 18.7 kg/d) across all periods of our experiment and increased body temperature (39.6 vs. 39.0 °C) during the heat challenge. Betaine supplementation reduced maximum body temperature during the pre-challenge period (39.2 vs. 39.6 °C) but not during the heat challenge (40.3 °C). Cows fed canola oil had greater declines in dry matter intake (5.4 vs 2.7 kg DM) and energy corrected milk (1.3 vs. 1.0 kg) from the pre-challenge to the heat challenge than other cows. Contrary to our expectations, the combination of fat and betaine supplements did not result in a clear benefit in terms of milk production or body temperature. Further work is warranted to understand the interactions between diet and hot weather.
... p<0.01). Moallem et al. (2010) indicated that THI's primary negative effect is a depression of RT, which subsequently led to a reduction in DMI, followed by a decline in milk yield. A statistically significant effect of THI on RT was identified, with RT decreasing as THI increased (Mishra et al. 1970). ...
... observed that with an increase in air temperature above 27 to 28°C, the rumination process was severely affected in Romanian Black and White multiparous cows. Moallem et al. (2010) indicated that the primary negative effect of the high THI is a depression of RT, which subsequently led to a reduction in DMI, followed by a decline in milk yield. ...
... However, Bernabucci et al. (2010) recently showed that reduced nutrient intake (an indirect effect of heat) accounts for only about 35% of the heat stress-induced decrease in milk synthesis. Moallem et al. (2010) indicated that the primary negative effect of the high temperature--humidity index (THI) was a depression of rumination time (RT), which subsequently led to a reduction in DMI, followed by a decline in milk yield. These authors suggested that rumination time plays a pivotal role in the negative effect of heat stress on DMI and, consequently, on milk production. ...
The aim of this study was to evaluate biomarkers of heat stress (HS) from an automatic milking system (AMS), the relationships between measurements of the temperature-humidity index (THI), reticulorumen pH and temperature, and some automatic milking systems parameters in dairy cows (rumination time (RT), milk traits, body weight (BW) and consumption of concentrate (CC)) during the summer period. Lithuanian Black and White dairy cows (n=365) were selected. The cows were milked with Lely Astronaut® A3 milking robots with free traffic. Biomarkers were collected from the Lely T4C management program for analysis. The pH and temperature of the contents of the cow reticulorumen were measured using specific Smax-tec boluses. The farm zone's daily humidity and air temperature were obtained from the adjacent weather station (2 km away). According to this study, during HS, the higher THI positively cor- relates with milk lactose (ML), which increases the risk of mastitis and decreases CC, RT, BW, MY, reticulorumen pH, and F/P. Some biomarkers of HS can be milk yield, milk lactose, somatic cell count, concentrate intake, rumination time, body weight, reticulorumen pH, and milk fat - protein ratio. We can recommend monitoring these parameters in the herd management program to identify the possibility of heat stress.
... Generally, cows can keep their body temperature at a constant level by convection and conduction (Kadzere et al., 2002) but they cannot release their inner metabolic heat (Allen et al., 2015;Bernabucci et al., 2014;Broucek et al., 2007;Purwanto et al., 1990;West, 2003) during an increase of surrounding temperature and humidity (Ammer et al., 2016;West, 2003) above their thermal neutral zone from À -0.5 � C to 20 � C (Hahn, 1999;Johnson, 1987) or, rather, between 5 � C and 25 � C (Berman et al., 1985;Gantner et al., 2017;Roenfeldt, 1998). Temperatures above cow's thermal neutral zone lead to displaced animal physiological status (Moretti et al., 2017) and production (Ammer et al., 2016;Collier et al., 2017;De Rensis et al., 2015;Moallem et al., 2010;Noordhuizen and Bonnefoy, 2015;Soriani et al., 2013), especially in milk yield (MY) (Gorniak et al., 2014;Schüller et al., 2013;West, 2003), but targeted production goals are related to an increase of MY (Gantner et al., 2017;Hansen, 2000;Nielsen et al., 2000;van Arendonk and Liinamo, 2003). ...
... In addition, Weary et al. (2009) and Bar and Solomon (2010) reported that imbalances in animal welfare, such as heat stress, could be detected by a decrease in rumination time (RT). On the other hand, RT is positively correlated with MY (Antanaitis et al., 2018;Moretti et al., 2017;Stone et al., 2017) and therefore, this targeted goal of production is endangered during heat stress by lowered RTs in cows Moallem et al., 2010;Soriani et al., 2013). In the thermal neutral zone, the daily RT of adult cows reaches 276-624 min per d (Adin et al., 2009;Beauchemin and Yang, 2005;Beauchemin et al., 1989;Dado and Allen, 1994;Hoy, 2014Hoy, , 2015Kononoff et al., 2003;Storm and Kristensen, 2010;Yang and Beauchemin, 2006), which incorporates a rhythmic procedure of regurgitation, remastication, salivation and reswallowing (Erina et al., 2013;Schirmann et al., 2016). ...
... In our study, we found that RT was positively correlated with MY and negatively correlated with THI, which was in agreement with the findings of Moallem et al. (2010) and Stone et al. (2017), who showed that RT and MY are positively correlated. This result was confirmed by Soriani et al. (2012), Soriani et al. (2013) and Moretti et al. (2017). ...
The dairy industry in regions with moderate climates, such as Central Europe, will be increasingly challenged in the future by climate change. The problem of heat stress will especially affect dairy husbandry in naturally ventilated barns (NVB). The approach of the study was to determine a heat stress threshold of the average daily temperature-humidity index (THI) that results in changes in the daily rumination time (RT) of lactating, high-yielding cows. The data set was composed of a high sample size of 183 cows and long-duration measurements of 21240 daily observations over two years from June 2015 to May 2017, which were collected in an NVB in Groβ Kreutz, Germany. The THI was calculated in 5-min intervals by data from several sensors in different positions inside the barn. Additionally, every cow from the herd of an average of 53 cows in the experimental procedure was wearing a neck collar with a Lely Qwes HR system that provided the RT 24 h a day (12 2-h recordings were summarized). The study showed that heat stress also negatively influenced RT in moderate climates. The heat stress threshold of 52 THI was determined by broken-stick regression and indicated changes of RT of lactating dairy cows in Germany. During the experimental period, the heat stress threshold for RT was reached from April to September for up to 720 h per month. The changes in RT to the heat stress threshold will be affected by cows' characteristics. Therefore, we considered several cow-related factors, such as milk yield (MY), lactation number (LN), lactation stage (days in milk, or DIM) and pregnancy stage (P) to better understand cows' individual reactions to heat stress. Multiparous, high-yielding cows in later lactation stages are potentially more strongly affected than other cows.
... It is observed, an inverse relation between the feeding behavior parameters after the delivery of the ration (indicated with arrows on figure), as the time dedicated to feeding and dry matter consumption increases the time dedicated to ruminating and lying down decreases. A decrease in the rumination activity of dairy is described as an indicator of stress and anxiety (Herskin et al., 2004;Bristow and Holmes, 2007); it is commonly observed in overcrowding conditions (Grant and Albright, 2006); during heat stress (Tapk and Sahin, 2006;Moallem et al., 2010;Soriani et al., 2013), and this alteration is also common during estrus (Reith and Hoy, 2012). ...
... Cows modify their rumination time in response to heat stress thresholds, which are lower in temperate zones than in hotter locations (Müschner-Siemens et al., 2020). Decreased rumination time is a primary sign in dairy cows under conditions of high THI and that causes a reduction in dry matter intake (Moallem et al., 2010). A reduction in dry matter intake was observed in the days after the reduction in rumination time as a consequence of an increase in THI (Soriani et al., 2013). ...
... Efficiency calculations are summarized in Table 3. Conversion of DMI to milk did not differ between groups, but conversion of DMI or energy consumed to 4% FCM was higher in MF than in LF (p < 0.01). Weiss et al. [30] reported that supplementation of calcium salts of fatty acids (with about 6% total fat in the diet) increased efficiency of conversion of DMI into milk or FCM (4%), similarly to previous findings of Moallem et al. [31], who used a diet supplemented with CS-PFA that provided 6.6% of the total fat in the diet compared with 5.1% in controls. Furthermore, Wu et al. [22] found that feeding high rates of CS-PFA increased the efficiency of conversion of DMI into FCM (but not into milk). ...
... The total BW gain through the whole of the present study tended to be higher in LF than in HF cows (27.3 vs. 16.8 kg; p < 0.1; Table 3), which is surprising because the calculated energy balances were similar between groups. Nevertheless, this trend of lower BW gain resulting from diets in which high fat content replaced carbohydrates was found Animals 2022, 12, 2081 9 of 13 elsewhere [31,34]; this indicates that there was differing partitioning of energy resources, i.e., less energy allocated to body mass retention under high-fat diets. ...
Instability in grain prices led to continuing worldwide growth in the proportion of fat supplements in lactating cows’ rations. However, fat supplementation was associated with decreases in feed intake, rumen fermentation, and feed digestibility. The present objectives were to test the effects of high-fat diets from calcium salts of palm oil fatty acids (CS-PFA) in lactating cow rations containing high proportions of concentrate, on feed intake, milk yields, rumen environment, and digestibility. Forty-two multiparous mid-lactation dairy cows were assigned to three treatments, designated as low fat (LF), moderate fat (MF), and high fat (HF) that contained (on DM basis), respectively, (i) 4.7% total fat with 1.7% CS-PFA, (ii) 5.8% total fat with 2.8% CS-PFA, and (iii) 6.8% total fat with 3.9% CS-PFA. Rumen samples were collected for pH, ammonia, and volatile fatty acid (VFA) measurements, and fecal grab samples were collected for digestibility measurements. A numerical trend of decreasing dry matter intake with increasing CS-PFA in diet was observed: 28.7, 28.5, and 28.1 kg/day in LF, MF, and HF, respectively (p < 0.20). No differences between treatments were observed in milk yields and milk-fat percentages, but protein percentage in milk tended to fall with increasing dietary CS-PFA content (p < 0.08), which resulted in 6.4% smaller protein yields in the HF than in the LF group (p < 0.01). Milk urea nitrogen was 15.3% higher in HF than in LF cows (p < 0.05). Rumen pH was higher at all sampling times in the MF and HF than in the LF cows. Concentrations of propionic acid and total VFA were higher in LF than in MF and HF cows. The apparent total-tract digestibility of dry matter was higher with LF than with HF (p < 0.002), and that of organic matter was lowest with the HF diet (p < 0.005). The apparent NDF digestibility declined with increasing dietary fat content, and it was 8.5 percentage points lower in HF than in LF cows (p < 0.009). Apparent fat digestibility increased with increasing dietary fat content, and it was higher by 10.4 percentage points in the HF than in the LF group (p < 0.004). In conclusion, diets with high concentrate-to-forage ratios, containing up to 6.8% total fat and 3.9% CS-PFA, negatively affected rumen fermentation and NDF digestibility in high-yielding dairy cows; however, the effects on yields were minor, indicating that, under specific circumstances, the inclusion of large amounts of CS-PFA in dairy cows’ rations with low fiber content is feasible.
... The temperature and humidity index (THI) is widely used to assess heat stress in dairy operations [8]. According to Moallem et al. [9], the major negative effect of the high heat-humidity index (THI) is a decrease in the rumination period, which leads to a reduction in dry matter intake and a consequent decrease in milk yield. Bernabucci et al. [10] report that a reduced nutrient intake in the heat-stressed cows contributes to a reduction in milk synthesis to about 35%. ...
... Increase in the fat content in milk under hot conditions can be influenced by the addition of suitable energetic feeds. Moalem et al. [9] found that in hot and humid environment, the addition of fat to the feed ration had a positive effect on increasing the fat content of milk, while on the contrary, in the group of cows with the addition of corn in the feed ration there was a decrease in the fat content compared to the control group. In contrast to the results of our experiment, Anzures-Olvera et al. [15] report that milk had a higher content of fat and protein during the summer (p < 0.01), but the number of somatic cells was similar to ours in the winter. ...
The aim of this study was to evaluate the influence of environmental housing conditions on the milk yield of dairy cows. Measurements were taken in the summer period from June to September 2020 and in the winter period during January 2021 on a large-capacity farm of Holstein Friesian cattle. Cows were housed in free stall barn with the lying boxes and selected during the second or third lactations, in the summer period from the 51st day to the 135th day and in the winter period from the 64th day to the 120th day of lactation. The average temperature in the housing was 23 °C in summer, and 7.05 °C in winter. The average THI (thermal humidity index) value in summer was 70.43, but during the day the THI values sometimes reached 75. The dairy cows were therefore exposed to heat stress during summer. Increasing THI and temperature values negatively affected the milk yield, as there was a negative correlation between both THI and milk yield (r = -0.641; p <0.01) and temperature and milk yield (r = -0.637; p <0.01). Milk production in winter was at 58.77 kg per day and in summer at 49.55 kg per day. In the summer, the milk had a significantly lower content of fat (p <0.05), proteins (p <0.001), lactose (p <0.001), minerals (p <0.001) and conversely, a higher number of somatic cells (p <0.01). These results show that worse environmental conditions during the summer negatively affected the level of milk yield and the composition of the cows’ milk.
... Under warm conditions, the rumen is consumed as a water reservoir during the heat of the day when it is most needed and as a fermentation tub when dryness rates are lower (Kadzere et al. 2002), which might be the possible cause for decrease of rumination during the warmer part of the day with the rise of water intake. Thus, the decrease of rumination plays a necessary role in the adversative effect of heat stress (Moallem et al. 2010). ...
... Under hot conditions, the rumen is used as a water reservoir during the heat days when it is most needed and as a fermentation vat when dehydration rates are lower (Kadzere et al. 2002), which might be the possible reason for reduction of rumination during the hotter part of the day with the increase of water intake. Thus, the reduction of rumination plays a crucial role in the adverse effect of heat stress (Moallem et al. 2010). ...
This study aimed to inspect the effects of consuming two different doses of the brown seaweeds "Sargassum latifolium" by heat stressed growing Barki ram lambs for 60 days on their growth performance, physiological and behavioral responses. Twenty Barki ram lambs 6-8 months old with average of 29.26 ± 2.09 kg live body weight were divided into four equal experimental groups. Lambs in the first group were kept in comfortable environmental conditions and were not offered seaweed and assigned as control (C). Animals in the second group were exposed to heat stress and were offered the diet without seaweed (T0). Animals in the third (T1) and fourth (T2) groups were exposed to heat stress and were supplemented with 2 and 4% (from CFM) brown seaweeds, respectively. Feed intake and body weight were recorded daily. Complete blood count and plasma biochemical parameters were assessed biweekly while behavioral responses were measured in the last week of the experiment. Animal had brown seaweeds in T1 and T2 groups increased (P<0.01) average daily gain and total body weight gain as compared to their counterparts exposed to heat stress (T0). Moreover, lambs of T2 achieved the best feed conversion ratio (8.37). Seaweed supplementations increased (P<0.05) leukocyte, hematocrit and hemoglobin concentration. Feeding lambs with a diet containing 4% brown seaweeds increased (P<0.01) serum total protein, albumin, potassium level, but decreased (P<0.01) serum total lipids, triglycerides, total cholesterol as compared with control ones. Supplementation with brown seaweeds affected significantly daily water intake and some behavioral parameters. It can be concluded that supplementation with brown seaweed (2% and 4% from CFM) to heat stressed Barki ram lamb in summer improved productive performance through improving growth rate, blood constituents, beside ingestive, standing and lying behavior.
... Under warm conditions, the rumen is consumed as a water reservoir during the heat of the day when it is most needed and as a fermentation tub when dryness rates are lower (Kadzere et al. 2002), which might be the possible cause for decrease of rumination during the warmer part of the day with the rise of water intake. Thus, the decrease of rumination plays a necessary role in the adversative effect of heat stress (Moallem et al. 2010). ...
... Under hot conditions, the rumen is used as a water reservoir during the heat days when it is most needed and as a fermentation vat when dehydration rates are lower (Kadzere et al. 2002), which might be the possible reason for reduction of rumination during the hotter part of the day with the increase of water intake. Thus, the reduction of rumination plays a crucial role in the adverse effect of heat stress (Moallem et al. 2010). ...
... Under warm conditions, the rumen is consumed as a water reservoir during the heat of the day when it is most needed and as a fermentation tub when dryness rates are lower (Kadzere et al. 2002), which might be the possible cause for decrease of rumination during the warmer part of the day with the rise of water intake. Thus, the decrease of rumination plays a necessary role in the adversative effect of heat stress (Moallem et al. 2010). ...
... Under hot conditions, the rumen is used as a water reservoir during the heat days when it is most needed and as a fermentation vat when dehydration rates are lower (Kadzere et al. 2002), which might be the possible reason for reduction of rumination during the hotter part of the day with the increase of water intake. Thus, the reduction of rumination plays a crucial role in the adverse effect of heat stress (Moallem et al. 2010). ...
... Upadhyay et al. [27] concluded that high THI values have a negative impact on milk productivity of cows. According to Moallem et al. [28], the main negative effect of high THI values is a decrease in the rumination period, which leads to a decrease in dry matter intake and a subsequent decrease in milk yield. Predicting HS and adequately and timely responding to this problem can significantly reduce its negative effects. ...
The study was conducted in the milking parlor of a cattle farm with a capacity of 400 cows of the Holstein-Friesian breed. The milking installation was a double 8 "Herringbone" type without windows, and the roof was constructed of glass. The reporting of temperature, air humidity and temperature-humidity index (THI) was performed three times during each milking (at the start, in the middle and at the end of milking) with measurements repeated during the morning, noon and evening milking. The highest mean and maximum daytime air temperature values were recorded in summer and spring. Although the average values for the spring season were lower than those for summer (by about 4 ⁰ C), the maximum values reached were equally high – 31.4 ⁰ C. In terms of relative air humidity, the highest mean values were reported for the winter sea-son – 82.39%. For the other seasons, the relative humidity values were on average high and close in value - from 62.51 to 67.46%. In THI, the highest average daily and maximum values were re-ported in the summer months - 73.41 and 80, respectively.
... In Iran, rumen-protected glutamine supplementation was reported to improve the redox status of heat-stressed Afshari lambs during the fattening period when supplemented at a concentration of 0.2 g/kg body weight (Fez et al. 2021). Moallem et al. (2010) supplemented calcium salts of fatty acids of palm oil distillate at a concentration of 0.3 kg/d (1.5% of diet) in Israeli-Holstein cows and reported increase in the metabolic efficiency under hot and humid conditions. Likewise, Halakoo et al. (2020) studied the effects of different fat sources in heatstressed lambs of four different breeds (Zel, Dalagh, and their hybrids with Romanov). ...
Climate change is currently an undisputable reality and an increased environmental temperature in recent times is one of the indicators for the changing climatic scenario. “Heat stress” detrimentally affects ruminant production, causing adverse economic consequences to the producers. Therefore, mitigating the adverse impact of heat stress on ruminants may be highly beneficial in terms of improving/sustaining productive performance and thereby the livelihood security for the farming community. The strategies to sustain livestock production in the changing climate scenario must invariably follow two different approaches short-term (e.g., housing management, nutrition, etc.) and long-term (e.g., genetics and health management) strategies. There are several nutritional approaches exist to reverse the adverse impacts of heat stress. Specifically, altered ratio of roughage (forage)-to-concentrate, additional feeding of fats, probiotics, antioxidants, electrolytes, and mineral mixture may prove beneficial to relieve the heat stress in ruminant. In this regard, the objective of this chapter is to project to the readers the various strategies that are available to ameliorate heat stress effect in ruminants with a special emphasis on nutritional interventions. Given the huge economic loss attributed to thermal stress in ruminant operations worldwide, the dietary fortification strategies discussed in this chapter would help relieve stress on one hand and sustain productivity of ruminants as well as farm sustainability on the other.
... Expanding the scope of genomic selection models to include a broader range of environmental stressors allows breeders to better choose animals with enhanced adaption and resilience features. Precision Livestock Farming involves the integration of sensor technology, Internet of Things (IoT), and big data analytics to enable the real-time monitoring of individual animal health, behavior, and performance [40,38].The advancements in CRISPR gene editing technology present potential options for introducing or strengthening certain features linked to enhanced disease resistance, adaptability to different climates, and general strength and resilience. Environmental DNA (eDNA) monitoring involves the utilization of eDNA to assess ecosystems and gain understanding about the influence of animals on their environment. ...
The ability of an animal to adapt to transient environmental difficulties and regain its pre-challenge state is known as resilience, and it is a dynamic and multifaceted characteristic. The ability of the herd to adapt to often shifting and uncertain environmental conditions can be strengthened by resilient animals. The capacity of contemporary technologies to capture many performance metrics of individual animals in real time is a significant advancement in assessing the resilience of farm animals. Resilience, however, cannot be measured directly; instead, quantitative resilience indicators must be derived from mathematical models with biologically meaningful characteristics. This work aimed to review and demonstrate, via examples, several modeling methodologies used with this new type of data (high-frequency recording) in order to identify and measure animal reactions to disturbances.
... The current study showed that the RUT in summer and spring is less than that in winter and autumn. Tapki and Şahin (2006) and Moallem et al. (2010) showed that RUT is reduced during heat stress in dairy cows. FI depends on EAT and intake per unit time. ...
The aims of this study were to estimate genetic parameters and to identify genomic regions associated with eating time (EAT) and rumination time (RUT) in Holstein dairy cows. Genetic correlations among EAT, RUT and milk yield traits were also estimated. The data were collected from 2019 to 2022 in 6 dairy herds located in the Walloon Region of Belgium. The data set consisted of daily EAT and RUT records on 284 Holstein cows, from which 41 cows had records only for the first parity, 101 cows had both first and second parities records, and 142 cows had records only for the second parity. The number of daily EAT and RUT records in the first-parity (P1) and second-parity (P2) cows were 18,569 (on 142 cows) and 34,464 (on 243 cows), respectively. Data on 28,994 single nucleotide polymorphisms (SNP) located on 29 Bos taurus autosomes (BTA) of 747 animals (435 males) were used. Random regression test-day models were used to estimate genetic parameters through the Bayesian Gibbs sampling method. The SNP solutions were estimated using a single-step genomic best linear unbiased prediction approach. The proportion of genetic variance explained by each 20-SNP sliding window (with an average size of 1.52 Mb) was calculated, and regions accounting for at least 1.0% of the total additive genetic variance were used to search for candidate genes. Mean (standard deviation (SD)) averaged daily EAT and RUT were 327.0 (85.66) and 559.4 (77.69) min/d for cows in P1 and 316.0 (82.24) and 574.2 (75.42) min/d for cows in P2, respectively. Means (standard deviation; SD) heritability (h2) estimates for daily EAT and RUT were 0.42 (0.09) and 0.45 (0.06) for cows in P1 and 0.45 (0.04) and 0.43 (0.02) for cows in P2, respectively. Mean (SD) daily genetic correlations between daily EAT and RUT were 0.27 (0.07) for P1 and 0.34 (0.08) for P2. Genome-wide association analyses identified 6 genomic regions distributed over 5 chromosomes (BTA1, BTA4, BTA11, BTA14 (2 regions), and BTA17) associated with EAT or RUT. The findings of this study increase our preliminary understanding of the genetic background of feeding behavior in dairy cows; however, larger data sets are needed to determine whether EAT and RUT might have the potential to be used in selection programs.
... They argued that TMR could mitigate heat stress-induced milk fat depression by maintaining the balance between forage and concentrate intake and ensuring sufficient fiber for proper rumen function. Moallem et al. [50] pointed out that the primary adverse effect of elevated THI levels is the reduction in rumination time, subsequently leading to decreased dry matter intake and, consequently, reduced milk yield. The release of somatic cells in milk is influenced by various factors, including milk productivity, animal health, management practices, and environmental conditions, as elaborated upon in the following discussion [21]. ...
Simple Summary
This comprehensive study focused on dairy farms in northeastern Iran to investigate how changing seasons, months, and temperature–humidity index (THI) affect milk production and quality. Data from ten randomly selected dairy herds were collected, including daily milk production records and milk samples for analysis. The study closely examined the influence of season, month, and THI on milk yield, quality, and cow health. Our findings revealed that winter had the highest milk yield, fat, protein, solids-not-fat (SNF), and pH levels, while somatic cell counts (SCC) and total bacterial counts (TBC) were the lowest during this season. The highest values for milk yield, fat, and pH occurred in January, and March showed the highest protein and SNF levels. December had the lowest SCC and TBC values. Our results emphasize the significant impact of THI on milk production and quality, providing valuable insights for effective dairy management, especially in the face of climate change challenges.
Abstract
This current study addresses the knowledge gap regarding the influence of seasons, months, and THI on milk yield, composition, somatic cell counts (SCC), and total bacterial counts (TBC) of dairy farms in northeastern regions of Iran. For this purpose, ten dairy herds were randomly chosen, and daily milk production records were obtained. Milk samples were systematically collected from individual herds upon delivery to the dairy processing facility for subsequent analysis, including fat, protein, solids-not-fat (SNF), pH, SCC, and TBC. The effects of seasons, months, and THI on milk yield, composition, SCC, and TBC were assessed using an analysis of variance. To account for these effects, a mixed-effects model was utilized with a restricted maximum likelihood approach, treating month and THI as fixed factors. Our investigation revealed noteworthy correlations between key milk parameters and seasonal, monthly, and THI variations. Winter showed the highest milk yield, fat, protein, SNF, and pH (p < 0.01), whereas both SCC and TBC reached their lowest values in winter (p < 0.01). The highest values for milk yield, fat, and pH were recorded in January (p < 0.01), while the highest protein and SNF levels were observed in March (p < 0.01). December marked the lowest SCC and TBC values (p < 0.01). Across the THI spectrum, spanning from −3.6 to 37.7, distinct trends were evident. Quadratic regression models accounted for 34.59%, 21.33%, 4.78%, 20.22%, 1.34%, 15.42%, and 13.16% of the variance in milk yield, fat, protein, SNF, pH, SCC, and TBC, respectively. In conclusion, our findings underscore the significant impact of THI on milk production, composition, SCC, and TBC, offering valuable insights for dairy management strategies. In the face of persistent challenges posed by climate change, these results provide crucial guidance for enhancing production efficiency and upholding milk quality standards.
... Furthermore, Weary et al. [21] and Bar and Solomon [22] revealed that animal welfare imbalances, such as heat stress, might be recognized by a decrease in rumination time (RT). However, because RT is positively connected with milk yield [23,24], the desired aim of production is jeopardized by heat stress decreasing RTs in cows [25,26]. We recently discovered that the influence of HS on reticulorumen parameters enhanced the risk of cow acidosis and activity levels. ...
Simple Summary
Heat stress (HS) has a major negative impact on dairy farming. Heat stress in dairy cows can reduce milk production, decrease reproduction rates, and significantly affect animal welfare. Non-invasive methods are commonly used to quantify stress reactions based on changes in behavioral and physiological responses. In this study, a group of nine healthy Lithuanian Black-and-White cows was systematically chosen for the trial, during which their behaviors were recorded using RumiWatch noseband sensors (RWS). We recognized that modern tools like RWS, which integrates a noseband sensor, can be utilized to identify HS and its effects on ruminating, eating, and locomotion behavior during heat stress.
Abstract
Heat stress (HS) significantly impacts dairy farming, prompting interest in precision dairy farming (PDF) for gauging its effects on cow health. This study assessed the influence of the Temperature–Humidity Index (THI) on rumination, eating, and locomotor activity. Various parameters, like rumination time, drinking gulps, chews per minute, and others were analyzed. The hypothesis was that precision dairy farming technology could help detect HS. Nine healthy Lithuanian Black-and-White cows were randomly selected for the trial. RumiWatch noseband sensors recorded behaviors, while SmaXtec climate sensors monitored THI. The data collection spanned from 14 June to 30 June. Cows in the THI class ≥ 72 exhibited reduced drinking time (51.16% decrease, p < 0.01), fewer chews per minute (12.9% decrease, p < 0.01), and higher activity levels (16.99% increase, p < 0.01). THI showed an inverse correlation with drinking time (r = −0.191, p < 0.05) and chews per bolus (r = −0.172, p < 0.01). Innovative technologies like RumiWatch are effective in detecting HS effects on behaviors. Future studies should explore the impact of HS on RWS biomarkers, considering factors such as lactation stage, number, yield, and pregnancy.
... Animals in HS environments tend to alter their natural behavior in order to maintain euthermia in comparison with animals in thermoneutral conditions. Rumination is reduced in cows [11] with shifts in rumination patterns, with more than 60% of the daily rumination occurring at night [12]. Moreover, standing bouts have been demonstrated to increase in hot temperatures [13] as an attempt to enhance the body surface area and support cooling. ...
Heat stress (HS) negatively affects animal productivity and welfare. The usage of wearable sensors to detect behavioral changes in ruminants undergoing HS has not been well studied. This study aimed to investigate changes in sheep’s behavior using a wearable sensor and explore how ambient temperature influenced the algorithm’s capacity to classify behaviors. Six sheep (Suffolk, Dorset, or Suffolk × Dorset) were assigned to 1 of 2 groups in a cross-over experimental design. Groups were assigned to one of two rooms where they were housed for 20d prior to switching rooms. The thermal environment within the rooms was altered five times per period. In the first room, the temperature began at a thermoneutral level and gradually increased before decreasing. Simultaneously, in the second room, the temperature began at hot temperatures and gradually decreased before increasing again. Physiological responses (respiratory rate, heart rate, and rectal temperature) were analyzed using a linear mixed-effects model. A random forest algorithm was developed to classify lying, standing, eating, and ruminating (while lying and standing). Thermal stress shifted daily animal behavior budgets, increasing total time spent standing in hot conditions (p = 0.036). Although models had a similar capacity to classify behaviors within a temperature range, their accuracy decreased when applied outside that range. Although wearable sensors may help classify behavioral shifts indicative of thermal stress, algorithms must be robustly derived across environments.
... In the present study, the rumination time reduced in T as compared to C, which might be an effort of T group lamb to produce less metabolic heat during the day time to support the reduced heat load in high-temperature exposure which helped the animal to maintain body temperature (Rashid et al., 2013;Soriani et al., 2013). In accordance with our observations, researchers also reported reduced rumination in ruminants under heat stress (Hirayama et al., 2004;Moallem et al., 2010). Rumination generally generates heat through The behavior of the individual animals was recorded for 2 days in each week from morning 0800 hours to evening 1700 hours. ...
... In contrast to these previous reports though, we found that rumination time slightly increases until THI category 4. This is difficult to explain, since rumination time is dependent on dry matter intake (Moallem et al. 2010) and, therefore, should also have decreased. The breakpoint for heavy breathing time was estimated at a THI of 84, indicating that this measure starts to increase at the emergency level (Moretti et al. 2017). ...
Heat stress presents one of the most urgent challenges to modern dairy farming, having major detrimental impacts on cow welfare, health, and production. Understanding the effect of cow factors (reproductive status, parity, and lactation stage) on the physiological and behavioural response to hot weather conditions is essential for the accurate detection and practical application of heat mitigation strategies. To study this, collars with commercial accelerometer-based sensors were fitted on 48 lactation dairy cows to record behaviour and heavy breathing from late spring to late summer. The temperature-humidity index (THI) was calculated from measurements of 8 barn sensors. We found that, above a THI of 84, cows in advanced pregnancy (>90 days) spent more time breathing heavily and less time eating and in low activity than other cows, while cows in early pregnancy (≤90 days) spent less time breathing heavily, more time eating and in low activity. Cows with 3+ lactations showed less time breathing heavily and in high activity and more time ruminating and in low activity than cows with fewer lactations. Although lactation stage interacted significantly with THI on time spent breathing heavily, ruminating, eating, and in low activity, there was no clear indication at which lactation stage cows were more sensitive to heat. These findings show that cow factors affect the cow's physiological and behavioural response to heat, which could be used to provide group-specific heat abatement strategies, thereby improving heat stress management.
... In a study involving 515 dairy cows in 7 experiments, the cows consumed an average of 7.7 meals per day, with a time interval between meals of at least 29 minutes (De Mol et al., 2016). Moallem et al. (2010) indicated that the primary negative effect of high THI is a depression of rumination time, which subsequently led to a reduction of dry matter intake, followed by a decline in milk yield. When temperature exceeds the threshold values, a 1 °C increase in daily mean temperature reduced rumination time by 5.12 min per day and reduced rumination efficiency by 0.07 kg DM per cow per hour (Ji et al., 2020). ...
The objective of this study was to investigate the influence of surrounding temperature and humidity in different periods of the year on eating and rumination time on ilk yield and chemical composition in Simmental cows at late lactation (over 150 days in milk, DIM). Ambient temperature and relative humidity were registered every hoursing data logger Testo 174H. Rumination time and eating time data were collected using an automatic system – GEA CowScout Neck. It was noticed that different values of THI temperature and humidity index) affect eating time (p<0.01), rumination time (p<0.01), milk yield (p<0.05) as well as milk fat content (p<0.05). The average value of THI1 (52.55) had a positive effect on eating time (307.2 min/day), rumination time (384 min/day), milk yield (28.97 kg/day), and milk fat content (4.25%), compared to the average value of THI2 (72.88), where the observed eating time was 259.2 min/day, rumination time 343 min/day, milk yield 26.21 kg/day and milk fat content 4.11%. An increased chewing time was achieved at lower value of THI, as well as higher milk yield and improved milk composition.
Keywords: dairy cattle, production performances, chewing activity, THI
... These findings were consistent with a previous study [56] that reported a similar trend in rumination time during different seasons except that rumination time remained increasing until the end of summer. Whereas in the current study rumination time declined in summer, which was potentially due to heat stress caused by the high temperature humidity index [66]. The seasonal effect on variation in rumination time was also related to the varying feeding regimes in each season. ...
This study investigated the variation in daily time spent grazing and rumination in spring-calved grazing dairy cows (n = 162) of three breeds, Holstein-Friesian (HFR), Jersey (JE), and KiwiCross (KC) with different breeding worth index, and in different years of lactation (1st, 2nd, 3rd, 4th). The cows were managed through a rotational grazing system and milked once a day at 05:00 a.m. The cows grazed mainly pasture and received supplementary feeds depending on the season. Automated AfiCollar device continuously monitored and recorded grazing time and rumination time of the individual cows throughout the lactation period for three study years (Year-1, Year-2, Year-3) with 54 cows per year. A general linear mixed model fitted with breed × lactation year with days in milk (DIM), breeding worth (BW) index value, individual cow, season, and feed, and their interactions was performed in SAS. Variance partitioning was used to quantify the effect size of study factors and their interactions. Individual cows, DIM, and BW (except Year-3) had effects on grazing and rumination times throughout the study years. Grazing time and rumination time were different for different seasons due to varying supplementary feeds. Grazing time varied among breeds in Year-2 and Year-3, and among lactation years only in Year-1. Although rumination time differed among breeds in Year-3, it remained the same within different lactation years. Grazing time and rumination time had a negative relationship with each other, and their regression lines varied for different seasons. The total variance explained by the model in grazing time was 36–39%, mainly contributed by the individual cow (12–20%), season (5–12%), supplementary feed (2–6%), breed (1–5%), and lactation year (1–6%). The total variance explained in rumination was 40–41%, mainly contributed by the individual cow (16–24%), season (2–17%), supplementary feed (1–2%), breed (2–8%), and lactation year (~1%). These findings could contribute to improving the measures for feed resource management during different seasons over the lactation period for a mixed herd comprising JE, HFR and KC breeds in different years of lactation.
... Dry cows respond to HS by reducing DMI, rumination and chewing time (Karimi et al. 2015). Decreased rumination time was previously associated with HS in lactating cows (Moallem et al. 2010;Soriani et al. 2013), is probably due to heat-induced panting, and can represent a strategy to limit endogenous heat production. In a recent study, HS heifers in late gestation tended to spend more time eating and less time ruminating than the corresponding cooled ones during the prepartum period, despite similar DMI (Toledo et al. 2022). ...
The final weeks of gestation represent a critical period for dairy cows that can determine the success of the subsequent lactation. Many physiological changes take place and additional exogenous stressors can alter the success of the transition into lactation. Moreover, this phase is pivotal for the final stage of intrauterine development of the fetus, which can have negative long-lasting postnatal effects. Heat stress is widely recognised as a threat to dairy cattle welfare, health, and productivity. Specifically, late gestation heat stress impairs the dam’s productivity by undermining mammary gland remodelling during the dry period and altering metabolic and immune responses in early lactation. Heat stress also affects placental development and function, with relevant consequences on fetal development and programming. In utero heat stressed newborns have reduced birth weight, growth, and compromised passive immune transfer. Moreover, the liver and mammary DNA of in utero heat stressed calves show a clear divergence in the pattern of methylation relative to that of in utero cooled calves. These alterations in gene regulation might result in depressed immune function, as well as altered thermoregulation, hepatic metabolism, and mammary development jeopardising their survival in the herd and productivity. Furthermore, late gestation heat stress appears to exert multigenerational effects, influencing milk yield and survival up to the third generation.
... Although rumination time is mainly affected by diet characteristics, others studies also reported a negative association between heat stress and rumination time in primiparous and multiparous lactating cows (Kazdere et al., 2002;Soriani et al., 2013), and in late-gestation dry cows (Karimi et al., 2015). In mature animals, it was postulated that depressing the rumination time might delay passage of the rumen digesta, which would reduce the ruminal capacity for additional food and thereby play a pivotal role in the negative effect of heat stress on DMI and, consequently, on milk production (Warren et al., 1974;Church, 1988;Moallem et al., 2010). However, this was not observed in nulliparous late-gestation heifers, as DMI was similar between treatments. ...
Exposure of dairy cows to heat stress negatively affects welfare and performance during all phases of the lactation cycle. Detrimental effects include decreased milk and reproductive performance, reduced immune status and health, and altered natural behaviors. While we understand how mature cows respond to heat stress, the effects of late gestation heat stress on pregnant heifers is still unknown. Automated monitoring devices were used to document the behavioral activity of heifers during the pre- (final 60 d of gestation) and postpartum (first 60 d of lactation) periods. Twenty-five pregnant Holstein heifers were housed in a free-stall barn and enrolled to heat stress (HT; shade; n = 13) or cooling (CL; shade, soakers and fans; n = 12) treatments during the last 60 days of gestation. All animals were provided active cooling postpartum. Upon enrollment, heifers were fitted with a leg tag, which measured daily lying time, number of steps, and standing bouts, and a neck tag that measured eating and rumination times. Rectal temperatures (RT) and respiration rates (RR) were measured thrice weekly during the prepartum period. Relative to CL, HT heifers had elevated RT (38.8 vs. 38.7 ± 0.04°C) and RR (59.6 vs. 44.4 ± 1.9 breaths/min) during the prepartum period. Heat-stressed heifers tended to spend more time eating (224 vs. 183 min/d) and less time ruminating (465 vs. 518 min/d) during the prepartum period compared to CL, but dry matter intake did not differ. During the postpartum period, HT heifers spent more time eating (209 vs. 180 min/d) during weeks 1–4 of lactation, but rumination time was similar. Lying time was reduced by 59 and 88 min per day during weeks −7 and −6 prepartum and 84 and 50 min per day during weeks 2 and 3 postpartum in HT heifers, relative to CL. The number of steps was greater for HT during the postpartum period, from weeks 2 to 9 (3019 vs. 2681 steps/d). Eating frequency was similar during pre- and postpartum periods, however, based on semi quantitative visualization of the smarttag reports, HT consumed larger meals at night during the pre- and postpartum periods compared with CL heifers. In summary, late-gestation exposure to heat stress affects the daily time budget of first lactation heifers during both the pre- and postpartum periods. Current insights of heat stress effects on behavioral responses of dairy heifers may contribute to the development of more effective management strategies to mitigate heat load.
... Greater lactate production decreases the availability of energy, reduces ruminal pH, and inhibits pHsensitive rumen bacterial growth, which gives rise to subacute ruminal acidosis (SARA), a well-known metabolic disorder that suppresses the production of milk in dairy cows (Russell and Rychlik, 2001;Khafipour et al., 2009;Zhao et al., 2019). Several authors have stated that the decrease in rumination time as a direct effect of heat is one of the reasons for ruminal pH reduction (Moallem et al., 2010;Soriani et al., 2013;Müschner-Siemens et al., 2020). Saliva, which serves as a buffering agent and is essential for isotonic function, decreases due to short rumination time . ...
Heat stress (HS) in dairy cows causes considerable losses in the dairy industry worldwide due to reduced animal performance, increased cases of metabolic disorders, altered rumen microbiome, and other health problems. Cows subjected to HS showed decreased ruminal pH and acetate concentration and an increased concentration of ruminal lactate. Heat-stressed cows have an increased abundance of lactate-producing bacteria such as Streptococcus and unclassified Enterobacteriaceae, and soluble carbohydrate utilizers such as Ruminobacter , Treponema , and unclassified Bacteroidaceae. Cellulolytic bacteria, especially Fibrobacteres, increase during HS due to a high heat resistance. Actinobacteria and Acetobacter , both acetate-producing bacteria, decreased under HS conditions. Rumen fermentation functions, blood parameters, and metabolites are also affected by the physiological responses of the animal during HS. Isoleucine, methionine, myo-inositol, lactate, tryptophan, tyrosine, 1,5-anhydro- D -sorbitol, 3-phenylpropionic acid, urea, and valine decreased under these conditions. These responses affect feed consumption and production efficiency in milk yield, growth rate, and reproduction. At the cellular level, activation of heat shock transcription factor (HSF) (located throughout the nucleus and the cytoplasm) and increased expression of heat shock proteins (HSPs) are the usual responses to cope with homeostasis. HSP70 is the most abundant HSP family responsible for the environmental stress response, while HSF1 is essential for increasing cell temperature. The expression of bovine lymphocyte antigen and histocompatibility complex class II (DRB3) is downregulated during HS, while HSP90 beta I and HSP70 1A are upregulated. HS increases the expression of the cytosolic arginine sensor for mTORC1 subunits 1 and 2, phosphorylation of mammalian target of rapamycin and decreases the phosphorylation of Janus kinase-2 (a signal transducer and activator of transcription factor-5). These changes in physiology, metabolism, and microbiomes in heat-stressed dairy cows require urgent alleviation strategies. Establishing control measures to combat HS can be facilitated by elucidating mechanisms, including proper HS assessment, access to cooling facilities, special feeding and care, efficient water systems, and supplementation with vitamins, minerals, plant extracts, and probiotics. Understanding the relationship between HS and the rumen microbiome could contribute to the development of manipulation strategies to alleviate the influence of HS. This review comprehensively elaborates on the impact of HS in dairy cows and introduces different alleviation strategies to minimize HS.
... In the present study, the rumination time reduced in T as compared to C, which might be an effort of T group lamb to produce less metabolic heat (Rashid et al., 2013) during the day time to support the reduced heat load in high-temperature exposure which helped the animal to maintain body temperature (Soriani et al., 2013). In accordance with our observations; researchers also reported reduced rumination in ruminants under heat stress (Hirayama et al., 2004;Moallem et al., 2010). Rumination generally generates heat through bacterial fermentation (Piccione et al., 2014) and it is a good indicator of animal welfare (Gregorini et al., 2012). ...
Extended hot summer is a major constrain in animal production in the semi-arid tropical region. However, the adult native sheep is well-adapted to this climatic condition. Nonetheless, the adaptability of growing lambs in summer conditions is yet to be explored for sustainable sheep production. Therefore, the present study was carried out to assess the effect of summer environment on the growing lambs under hot semi-arid region. For this purpose, sixteen Malpura weaner lambs of 3-4 months of age were selected and equally distributed into two groups, viz. C and T. The lambs of T groups were kept inside the psychometric chamber in different temperature and humidity schedules simulated with the summer average temperature and humidity of the last 10-year of the semi-arid tropics. The lambs of C groups were kept inside the pen in a thermocomfort environment with the same space availability of T group lambs. The lambs of both the groups were provided with adlibitum feed and water. The water intake, respiration rate (RR), pulse rate (PR), rectal temperature (RT) and skin temperature of T group lamb was significantly (P<0.05) higher as compared to C group lambs. The summer exposure (T) reduced (P<0.01) the feeding and rumination time whereas increased (P<0.01) the panting in lambs as compared to C group. The endocrine profile did not varied (P>0.05) with the simulated summer exposure of semi-arid region in lambs. The present study reflected that the native Malpura growing lamb modifies their behavior and thermoregulatory responses to counter the extreme summer of the semi-arid region.
... Healthy transition dairy cows spent more time ruminating and eating during the first 3 wk after calving than diseased cows [12]. Decreased rumination activity is consistent with earlier reports [33] in which the primary negative effect of elevated heat index is depression of rumination time, which subsequently leads to a reduction in dry matter intake, followed by decreased milk yield. Although estimates of milk yield (daily and 305-d ME milk) were affected by season, no differences were detected between temperature groups within season in the present study. ...
A retrospective study was conducted to determine if postpartum health, milk yield, and reproductive traits in addition to peripartum daily physical activities (resting, eating, active time, and rumination) differ in dairy cows having greater or lesser ear-surface temperatures during late gestation (Days 230–239) compared with contemporary herd mates within season. Herd records collected from Holstein heifers (n = 348) and dry cows (n = 503; second through seventh lactations) were fitted with SensOor ear tags to collect hourly ear-surface temperatures. Mean temperatures were calculated from 240 hourly measures during Days 230–239 of gestation and cows within season were grouped into two median temperature groups. On Days 230–239 of gestation during May through September (hotter months) cows with high (H, range of 33.67–38.89 °C, mean ± SEM = 32.9 ± 0.2 °C) or medium high (MH, 25.06–31.66 °C, 29.4 ± 0.2 °C) temperatures were grouped together (n = 209 per group). For comparable gestational days during October through April (colder months), cows with medium low (ML, 17.82–25.00 °C, 21.1 ± 0.2 °C) and low (L, −0.70 to 17.80 °C, 13.4 ± 0.2 °C) temperatures were grouped together (n = 216 per group). Prepartum traits including mean ear temperature, gestation length, days in milk at dry-off, days in close-up pen, previous 305-d milk yield, proportion of heifer calves born, and cow PTA for milk differed (P < 0.05) between seasons, but not between temperature groups within season, except predicted transmitting ability for milk was greater (P = 0.02) for ML than L cows. Postpartum treatment with antimicrobials occurred more (P = 0.02) often in H than MH cows, whereas more (P = 0.04) lameness and greater (P = 0.05) projected 305-d mature equivalent milk yield was observed in ML vs. L cows. No other health or reproductive traits were associated with temperature group, but many seasonal effects were observed across temperature groups. Less (P = 0.04) prepartum eating time during the last 10 d before calving was detected in L than in ML cows, less (P = 0.06) rumination time in ML than L cows, and more (P = 0.03) activity time was observed in H than MH cows. After calving, H cows were more (P = 0.03) active than MH cows and ML cows tended (P = 0.07) to be more active than L cows. In conclusion, late gestational ear-surface temperatures were associated with some postpartum health disorders and modifications in daily eating, ruminating, and active times during the transition period of gravid heifers and dry cows.
... Under heat stress conditions, formulation of diets that contain slightly greater neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations can help minimize the risk of ruminal acidosis associated with heat stress conditions. Additionally, inclusion of fat in higher fiber diets may help maintain energy intake under hot conditions (Staples, 2007) (Moallem et al., 2010). ...
Heat stress negatively affects the performance, health, and welfare of dairy cattle. Selection for increasing milk yields is lowering the minimum temperature-humidity index at which heat stress starts to depress milk production, and rising global temperatures exacerbates the problem. The average dairy cow in the USA experiences 96 heat stress days during the year if not cooled. Experience and research have shown that management and housing may alleviate the effects of warm environments on dairy cattle. For example, dietary interventions such as feeding melatonin and chromium supplementation may reduce the detrimental effects of heat stress on fertility. An effective strategy is altering the timing of feeding to take advantage of the lower nighttime temperatures. Some cattle are more heat tolerant than others, so breeding values for thermotolerance have been developed. Upgrading the slick-hair gene into high producing Holstein cattle is another approach of making dairy cattle more tolerant of high temperatures. In-vitro produced embryo transfer improves conception rates during heat stress but may be cost prohibitive. Housing design, including cooling systems, is the primary way to reduce heat stress. Fans and water soakers or misters increase evaporative cooling effectiveness. In the USA, there is continuous development in size, number, and position of fans, as well as schedules for soakers. Newer systems are designed to be more energy and water efficient. Tunnel barns and cross-ventilated barns are constructed to help direct cool airflow on to cows. Cooling of heifers and dry cows has been receiving more attention in the last decade. Recent research has shown that cows provided relief from thermal stress during the dry period give birth to heavier and healthier calves, produce more milk during the next lactation and have better immune response during the transition period. Late gestation heat stress of dairy cows also depresses milk production of their daughters and possibly granddaughters. In the USA, economic losses are estimated to be $87 per cow per year if dry cows were not cooled. We discuss various heat abatement strategies including management of feeding, reproduction, genetic selection and housing design and they will continue to receive greater emphasis in dairy production across the USA.
... Feeding time tended to be higher in shaded cows during morning feeding compared to unshaded cows, and the reason for this remains unclear. Moallen et al., [56] and Soriani et al., [53] observed reductions in the dry matter intake of lactating dairy cows in the next days when exposed to THI values > 76. In the present study, although the dry matter intake was not evaluated, shaded and unshaded cows ate the whole ration both in the morning and evening, affecting only the feeding time. ...
Cows are affected by environmental factors associated with warm weather conditions; however, little is known about the effect of shade access especially during the prepartum period of dairy cows in temperate regions. This study assessed the effect of shade on the behavior (lying, rumination, feeding, and drinking), body fat mobilization, and health status of outdoor-housed dairy cows during the prepartum period under temperate summer conditions. During the 3 weeks prior to calving, 24 multiparous Holstein cows were grouped (4 cows/group) and assigned to either an open corral without shade or with access to shade until calving. We daily measured shade use, lying, rumination, feeding, and drinking behavior. Weekly, prepartum non-esterified fatty acids (NEFA) and postpartum b-hydroxybutyrate (BHB) concentrations were measured. Clinical examination was periodically performed individually until 21 postpartum days. Shade use averaged 45.6, 46.0, and 19.8% during the hottest hours of the day (11–18 h) in weeks 3, 2, and 1 prior to calving, respectively. Shaded cows had higher values for rumination time and feeding time during the morning but spent less time drinking during the warmest hours than unshaded cows. NEFA and BHB concentrations and clinical diseases were similar between both treatments. These findings suggest that under temperate summer conditions the access to an artificial shade is an important resource, observing beneficial effects mainly on behavioral variables.
... On the other hand, when comparing treatments balanced by feeding regime (HS vs TNPF), there was a decrease of 5% in ruminal pH values in heifers under HS. According to several authors (Moallem et al., 2010;Müschner-Siemens et al., 2020;Soriani et al., 2013) and one of the most representative reasons that indicate the decrease in pH as a direct effect of heat is the decrease in rumination time (RT). The lower RT results in a decrease in buffering agents that enter the rumen (saliva as an isotonic function). ...
This study aimed to verify the effects of heat stress and dietary energy level on dry matter intake (DMI), water intake, total and partial ruminal and intestinal digestibilities, ruminal characteristics, physiological and digestive behavioral parameters in beef cattle. Six ruminally cannulated Nellore heifers (280 ± 12 kg) were used in a 6 × 6 Latin square experiment with six treatments and six periods of 21 days. The treatments consisted of a 2 × 2 + 2 factorial arrangement, with two temperatures during the day (thermoneutrality, TN: 24°C; and heat stress, HS: 34°C), two dietary energy levels (low- or high-energy concentration) and two additional treatments of animals maintained in TN conditions but pair-fed with the heifers in HS (PFTN). The HS decreased DM intake by about 16% and increase water intake by 25.5% respectively (P ≤ 0.01). Heifers maintained in TN and fed high-energy diet showed 17.3 and 14.3% greater ruminal dry matter (DM) and organic matter (OM) digestibilities compared to their HS counterparts. The DM intake rate (ki, h⁻¹) and digestion rates (kd, h⁻¹) were affected by environment and dietary energy level (P ≤ 0.01), which heifers in HS having lower ki and kd. Heifers in HS presented lower pH and greater ruminal temperature values (P ≤ 0.01). When PFTN treatments were compared vs. HS, there was a significant effect of temperature on acetic acid. Heifers that underwent HS showed 14 % less acetic acid. The ocular temperature, body temperature, heart rate, and respiratory rate were greater in HS heifers (P ≤ 0.01) than in TN. Heifers with low energy level diets showed 33% greater values of rumination time (P = 0.05) when compared to high energy levels independent of the temperatures. We concluded that adaptive response to heat seems important factors responsible for the alteration of DMI, water, and other nutritional fractions like OM, CP, and energy intake. On the other hand, increments in intestinal digestibility in zebu heifers suggest an adaptive response of the digestive tract to heat stress conditions.
... Lipid addition to the diets has been found to be promising in attenuating the effect of heat stress on animals as this decrease heat increment and increase the energy intake. The findings of Moallem et al. (2010) revealed a metabolic efficiency in high yielding cows supplemented with fat under hot and humid climates. Also, high fat diets improved growth performance of pigs under high temperature (Spencer et al., 2001). ...
Tropical environments are characterized by persistently high temperature and relative humidity and the harsh environmental conditions pose a serious limitation on the optimal performance of the animals raised in this region. Heat stress causes deleterious effects on welfare, immunology and physiology of farm animals with a resultant impact on their productivity as the use of body resources is re-organized and the metabolic priorities of animals shift away from production, growth, health and reproduction. It is imperative to understand the mechanisms involved in the thermoregulation of animals under tropical conditions in order to develop appropriate strategies for their improvement. This review focuses on the available data on the increasing global temperature and the adverse impact of tropical conditions on animals’ adaptive mechanism affected during thermal stress on production performance, intestinal and ileal microbiome, physiological responses, antioxidant system, metabolic responses, cellular and molecular response, adaptive mechanism strategies to heat stress and also strategies to palliate environmental stress on livestock under humid tropical conditions including environmental manipulation, genetic opportunity, epigenetic and feeding modification. Overall, the present review has identified the disturbance in the physiological indices of tropical livestock and the need for concerted efforts in ameliorating the adverse impacts of high ambient temperature aggravated by high humidity on livestock in tropical environments. Further research is needed on genotype-by-environment interaction on the thermotolerance of different livestock species in the tropics.
... Furthermore, these differences were detected under more moderate heat stress conditions when compared with other studies in freestall housing where higher thresholds have been used (THI > 80; Soriani et al., 2013). Moallem et al. (2010) reported that a reduction in rumination time is the primary negative effects of high THI, which leads to a decline in DMI and milk production. Studies have shown that metritic cows already have a reduction in feed intake (Schirmann et al., 2016) and rumination time (Liboreiro et al., 2015) compared with healthy cows. ...
The aims of this study were to determine changes in lying and rumination behavior of transition dairy cows that were healthy or affected by metritis during the autumn and spring calving season in a temperate climate and determine the effect of some weather variables (precipitation and heat stress) on these behaviors. A total of 103 multiparous cows were monitored during the autumn (February to April) and spring calving season (July to October) from 10 d before to 10 d after calving. Cows were chosen retrospectively by diagnosis of metritis [autumn season, (n = 11); spring season, (n = 13)] or as healthy [autumn season, (n = 25); spring season, (n = 25)] based on vaginal discharge characteristics evaluated during the first 10 days in milk. In all animals, electronic data loggers recorded lying (Hobo Pendant G Acceleration, Onset Computer Corp.) and rumination behavior (Hi-Tag rumination monitoring system, SCR Engineers Ltd.) during the study period. We included precipitation level (>1 mm/d = with rain, and ≤1 mm/d = without rain) and heat stress [no heat stress = temperature-humidity index (THI) < 68 vs. heat stress = THI ≥ 68] as weather factors that may have affected lying and rumination behavior during the spring and autumn season in a temperate climate, respectively. Metritis during the spring calving season was associated only with longer lying times (≥1.3 h/d) after calving. During the autumn calving season cows with metritis lay down longer the day of calving (∼2.1 h/d) and had fewer lying bouts of longer duration during the prepartum period compared with healthy cows. Rumination time did not differ by health status during the spring calving season, whereas cows with metritis during autumn ruminated 30, 21, and 24 min/d less than healthy cows during the prepartum, calving, and postpartum period, respectively. Precipitation and heat stress were associated with decreased daily lying and rumination time in sick cows. Our results indicate that differences in lying and rumination behavior depended on the metritis status, and support the idea that weather factors such as rainfall or heat stress requires to be considered in analyses of transition cow behavior in seasonal calving pasture-based dairy systems.
... In the present study, cows under heat stress (STRESS) reduced rumination time and, as shown above, reduced milk production, total DMI, and forage intake. In agreement with these results, other studies showed that, during summer, THI is negatively associated with milk production and DMI (Moallem et al. 2010;Soriani et al. 2013). Church (1988) explained that a reduced rumination time reduces the passage of digesta in the gastrointestinal tract and, therefore, also the possibility to ingest further feed by cows. ...
Heat stress is one of the most important problems that dairy cows have to face and the use of cooling systems is becoming more and more important. The first reaction that has the animal to cope with the environmental variations is to modify its behaviour. This study was aimed to investigate the effect of heat stress and a cooling system on the feeding behaviour of Italian Holstein Friesian dairy cows in late lactation. Two experiments were performed. In the first experiment, eight dairy cows were firstly kept 7 d under thermoneutral condition, and then under mild heat stress (temperature humidity index, THI, ranging between 72 and 78) for others 7 d. The second experiment consisted of 8 dairy cows used in a two-period cross-over design where the treatment was the use or not of a sprinkler system for cooling cows under mild heat stress. Cows were equipped with a noseband pressure sensor able to detect rumination and eating time, number of rumination and eating chews, number of rumination boluses and rumination intensity. Heat stress reduced rumination time, number of rumination chews and boluses (p < .05), and tended to reduce the number of eating chews (p < .10). Cooled cows increased rumination and eating time (p < .05), rumination intensity (p < .01), and the number of rumination and eating chews (p < .05). In conclusion, feeding behaviour was deeply influenced even by mild heat stress, which was effectively improved by the use of a sprinkler system.
• HIGHLIGHTS
• Mild heat stress reduced rumination time, number of rumination chews and boluses of dairy cows in late lactation
• Cooling cows with sprinklers was effective in alleviating heat stress in terms of feeding behaviour
... Rumination occurs especially during the night (Beauchemin, 1991) and dairy cows normally ruminate for 7-8 hours per day. Daily rumination time (RT) is affected positively by fiber intake and content in the diet (Adin et al., 2009), as well as by forage particle size (Krause et al., 2002); and negatively by diseases (DeVries et al., 2009;Liboreiro et al., 2015), calving (Soriani, et al., 2012;Büchel and Sundrum, 2014) and thermal stress (Moallem et al., 2010;Vizzotto et al., 2015). Studies have shown that RT monitoring may be implemented as a useful tool in the early detection of diseases (Soriani et al., 2012;Kaufman et al., 2016;Paudyal et al., 2016). ...
Daily rumination time (RT; min/d) is recognized as an important tool for assessing the health of dairy cows, which may depend on the disease, lactation stage and individual cows. Using a systematic review-meta-analysis, this study evaluated whether the variation in RT is effective for early detection of metritis and subclinical ketosis (SCK) in dairy cows in the pre and post-partum periods (from three weeks before to three weeks after calving). The research was carried out in four electronic databases - Scopus, Science Direct, Pubmed and Web of Science. The main inclusion criteria were original research; evaluation of RT in dairy cows; and use of RT for early identification of metritis and/or SCK in post-partum dairy cows. A random effect meta-analysis (MA) was conducted for each disease (metritis and SCK) separately, with the RT means of healthy and sick groups, measured in the pre and post-partum. The effect size used was the mean difference (MD).Twenty-two trials from six studies were included in the MA, involving 1,494 dairy cows. For metritis, four trials from three studies in the pre-partum period were considered as well as five trials from four studies in the post-partum. For SCK, six trials from four studies pre-partum and seven trials from five studies in the post-partum period were taken into consideration. The heterogeneity between studies for metritis was null (I² = 0%) and low (I² = 5.7%) in the pre-partum and in the post-partum, respectively. The MD of RT between healthy cows and those with metritis was different in the pre (MD =0.411 min/d; P < 0.001) and in the post-partum (MD =0.279 min/d; P < 0.001). In SCK, heterogeneity was high in the pre (I² = 69%) and in the post-partum (I² = 58.1%), and the MD of RT was similar between healthy and sick cows (P > 0.05). In a meta-regression, RT from primiparous cows showed a lower predicted value for MD (0.48 min. d; P < 0.05) compared to multiparous cows, and the increment in each unit of milk production decreased the predicted MD value by 0.08 min. d (P < 0.001). Our MA demonstrates that RT is a good predictor for early detection of metritis in pre and post-partum; however, it is not an adequate predictor for SCK. Further investigations using more frequent blood sampling and the same threshold values for BHB are required to assess the adequacy of rumination time to predict SCK.
... The dairy industry loses millions of dollars annually due to reduced milk production during the summer (West et al., 1999;St-Pierre et al., 2003;Stull et al., 2008;Ferreira et al., 2016;Polsky and von Keyserlingk, 2017). Over and above, heat stress conditions are associated with reduced eating (Moallem et al., 2010), reduced feed efficiency (Kadzere et al., 2002), impaired fertility (Schueller et al., 2014;Mellado et al., 2015), and cow discomfort (Honig et al., 2012) . ...
Technological progress enables individual cow's temperatures to be measured in real time, using a bolus sensor inserted into the rumen (reticulorumen). However, current cooling systems often work at a constant schedule based on the ambient temperature and not on monitoring the animal itself. This study hypothesized that tailoring the cooling management to the cow's thermal reaction can mitigate heat stress. We propose a dynamic cooling system based on in vivo temperature sensors (boluses). Thus, cooling can be activated as needed and is thus most efficacious. A total of 30 lactating cows were randomly assigned to one of two groups; the groups received two different evaporative cooling regimes. A control group received cooling sessions on a preset time-based schedule, the method commonly used in farms; and an experimental group, which received the sensor-based (SB) cooling regime. Sensor-based was changed weekly according to the cow's reaction, as reflected in the changes in body temperatures from the previous week, as measured by reticulorumen boluses. The two treatment groups of cows had similar milk yields (44.7 kg/d), but those in the experimental group had higher milk fat (3.65 vs 3.43%), higher milk protein (3.23 vs 3.13%), higher energy corrected milk (ECM, 42.84 vs 41.48 kg/d), higher fat corrected milk 4%; (42.76 vs 41.34 kg/d), and shorter heat stress duration (5.03 vs 9.46 h/day) comparing to the control. Dry matter intake was higher in the experimental group. Daily visits to the feed trough were less frequent, with each visit lasting longer. The sensor-based cooling regime may be an effective tool to detect and ease heat stress in high-producing dairy cows during transitional seasons when heat load can become severe in arid and semi-arid zones.
... Calcium salts of fatty acids are another alternative that could be used in heat stressed dairy cows. It has been reported that supplementation of calcium salts of fatty acids had no effect on milk yield in heat-stressed Israeli-Holstein dairy cows, but it increased the energy density of dairy cow diet dramatically, enhanced milk protein, milk yield per kg feed intake and reduced metabolic heat production (Moallem et al., 2010). Furthermore, (Serbester et al., 2005) reported that feeding with 2.54% calcium salts of fatty acids in the diet would increase 4% fat corrected milk and milk fat yield of midlactation Holstein dairy cows during summer. ...
In livestock production system, dairy breeds are typically more sensitive to heat stress than meat breeds. Higher producing dairy animals like Holstein dairy cattle are more susceptible since they generate more metabolic heat. Heat stress negatively influences intake, rumen physiology, milk production and composition in dairy animals. Due to the rise in global warming issues, it is expected that heat stress in dairy cows will be more widespread in the future. Heat stress in dairy animals directly affect feed intake and rumen physiological functions thereby reduces milk yield and negative impact on milk composition. To address the negative impact of heat stress in dairy animals, researchers have examined various available nutritional strategies, including dietary fiber, dietary fat, dietary microbial additives, vitamins, minerals, metal ion buffer, plant extracts, and other anti-stress additives. However, two major nutrients fiber and fats are easily available macronutrients that can alleviate the negative impact of heat stress in dairy animals. This review will provide evidence for the efficacy of these nutritional strategies to mitigate the negative effects of heat stress in dairy cows. Furthermore, information on this review may provide an appropriate dietary strategy to cope with heat stress at dairy farms.
... increased overall mean RT in T 2 over T 1 at both 6:00 and 14:00 h. Higher RT in dietary fat supplemented group over the control group was also reported by Gaughan and Mader (2009) and Moallem et al. (2010). Cho et al. (2014) also reported that high energy diet increased rectal temperature in cattle. ...
... For example, rumination time (RT) can be recorded for each individual cow under both CMS and RMS. Moallem, Altmark, Lehrer, and Arieli (2010) indicated that heat stress (high temperature-humidity index, THI) could depress RT. A decreased RT reduced milk production, leading to financial losses for the farm. ...
Robotic milking systems (RMS) have been demonstrated to reduce on-farm labour requirements and collect significant individual-level data in relation to animal health, welfare and production, but they are still largely underutilised. Studies on the relationship between heat stress, animal behaviour and robotic milking performance in a RMS are still insufficient. To model such a relationship, this study focused on analysing the data collected from a RMS system. Animal response indicators of heat stress assessment were rumination time (RT), milk temperature (MT) and daily milk yield (DMY). In addition, RMS milking behaviour, i.e. time of milking (TM), milking frequency (MF), milking duration (MD), milking speed (MS) and milk yield per milking (MY) were also monitored. A new index of rumination efficiency (REI) was created to evaluate rumination efficiency under heat stress, defined as the ratio between DMY and RT. Using multiple broken-line regression, it was found that a 1 °C rise in daily mean temperature could reduce RT by 5.12 min, decrease REI by 0.07 kg·cow⁻¹·h⁻¹, and increase low efficiency milking by 1%. Moreover, the study also found cows prefer to milk between 7:00–9:00AM, and 86% of milking events happened during this period. No significant correlation was found between heat stress and milking behaviour. However, delaying the first milking event of the day and controlling milking intervals to <4 h, was beneficial for REI and robotic milking performance.
... Zimbelman et al. (2010) showed that cows fed rumen-protected niacin had lower rectal and vaginal temperatures under moderate heat load. Among feed additives, controversial results were found for the effects of increasing the energy density in the ration of high-yielding cows under hot and humid climates and the effects of functional oils (oils that have functions beyond their energy value like castor oil, which comes from Ricinus communis) (Ghizzi et al., 2018) and/or fat (Moallem et al., 2010). Wang et al. (2010) showed that feeding supplemental saturated fatty acids (SFA) during heat stress decreased the body temperature during the hottest time of the day and increased milk yield. ...
The so-called global change refers to changes on a planetary scale. The term encompasses various issues like resource use, energy development, population growth, land use and land cover, carbon and nitrogen cycle, pollution and health, and climate change. The paper deals with challenges for dairy cattle production systems in Europe arising from climate change as one part of global changes. Global warming is increasing, and therefore ecosystems, plant and animal biodiversity, and food security and safety are at risk. It is already accepted knowledge that the direct and indirect effects of global warming in combination with an increasing frequency of weather extremes are a serious issue for livestock production, even in moderate climate zones like Central Europe. The potential and already-measurable effects of climate change (including increase in temperature, frequency of hot days and heat waves), in particular the challenges on grassland production, fodder quality, nutrition in general, cow welfare, health as well as performance of dairy production, will be reviewed. Indirect and direct effects on animals are correlated with their performance. There are clear indications that with selection for high-yielding animals the sensitivity to climate changes increases. Cumulative effects (e.g. higher temperature plus increased pathogen and their vectors loads) do strengthen these impacts. To cope with the consequences several possible adaptation and mitigation strategies must be established on different levels. This includes changes in the production systems (e.g. management, barn, feeding), breeding strategies and health management.
... Several studies have shown that THI predictions are currently underestimating the severity of heat stress on physiological responses in dairy cows West et al., 2003;Zimbelman and Collier, 2011). Physiological parameters, such as respiration rate (RR), heart rate (HR) and body temperature, have been demonstrated as adequate and timely indicators of heat stress in dairy cows (Costa et al., 2015a;Kadzere et al., 2002;Moallem et al., 2010). Among other major physiological parameters reported in the literature, RR and internal temperature have long been used as heat load indicators (Brown-Brandl et al., 2005;Gal� an et al., 2018;Gaughan et al., 2000). ...
Fat supplements are well known for their multiple beneficial effects on ruminant health, reproduction and productivity, and as a source for certain bioactive compounds in ruminant products. On the other hand, numerous phytochemicals have demonstrated the potential to improve rumen fermentation through modifying the volatile fatty acid (VFA) pattern to favour those with greater energy efficiency, boosting microbial protein synthesis, and decreasing methane emission and ruminal ammonia concentration. Savory is an aromatic plant rich in various phytochemicals (mainly carvacrol and flavonoids) that can alter ruminal metabolism of dietary fatty acids, potentially increasing the production of some bioactive compounds such as conjugated linoleic acids (CLAs). This study aimed to investigate combined effects of oil type (fish oil (FO) versus soybean oil (SO)) and the inclusion of savory (Satureja khuzistanica) plant (SP) in the diet on total tract digestibility of nutrients, rumen fermentation, milk yield and milk fatty acid profile in dairy cattle. Eight multiparous lactating Holstein cows were used in a replicated 4 × 4 Latin square design experiment with four diets and four 21-d periods. During each experimental period consisted of 14 days of adaptation and a 7-day sampling period, cows were randomly assigned to one of the four dietary treatments: the diet supplemented with 2% (DM basis) fish oil (FOD) or soybean oil (SOD), the FOD or SOD plus 370 g DM/d/head SP (FODs, SODs, respectively). The experimental diets were arranged in a 2 × 2 factorial design, with the fat sources as the first and SP as the second factor. The FO-supplemented diets had lower dry matter intake (DMI) and higher total tract digestibility than SO-supplemented diets (P < 0.05), and including SP in the diet improved total tract digestibility of dry matter (DM), organic matter (OM), ether extract (EE), and non-fibrous carbohydrates (NFC) (P < 0.05) without negatively affecting DMI. Rumen pH was lower with SO than with FO diets (P < 0.01) and increased with SP inclusion in the diet (P < 0.05). Total protozoa count and ruminal ammonia concentration decreased, and the branched-chain VFA (BCVFA) proportion increased with SP inclusion in the diet (P < 0.05). Milk production, as well as the concentration and yield of milk components (except lactose concentration) were higher with SO than with FO diets (P < 0.05), but these variables remained unaffected by SP. The milk concentrations of both non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) were lower with SO compared to FO diets, and these variables were reduced by SP (P < 0.01). The proportions of both mono- and polyunsaturated FA (MUFA and PUFA, respectively) in milk were higher with FO than with SO diets (P < 0.01), and their proportions increased by SP at the expense of saturated FA (SFA) (P < 0.01). Including SP in the diet increased the proportions of all the milk n-3 FA (C18:3c, C20:5, and C22:6) by 21%, 40%, and 97%, respectively, and those of conjugated linoleic acids (C18:2 (c9,t11-CLA) and C18:2 (t10,c12-CLA)) by 23% and 62%, respectively. There was no interaction between oil type and SP for the assessed variables. Fish oil, despite reducing milk production and milk components, was more effective than soybean oil in enriching milk with healthy FA. These findings also show promise for SP as a feed additive with the potential to improve total tract digestibility, rumen fermentation and milk FA composition.
Controlled studies have shown that heat stress abatement positively influences health, productivity, behavior, and reproductive performance of dairy cows during all stages of the lactation cycle. Based on previous findings, the present study focused on a better understanding of how seasonal changes affect the behavior of multiparous lactating dairy cows kept in typical free-stall housing with the objective to aid in the management of lactating cows exposed to variable environmental conditions. Automated monitoring devices (Nedap, the Netherlands) were used to assess behavioral activity of mature Holstein dairy cows during the “hot season” (HS; n = 19; July, August, and September) and the “cool season” (CS; n = 15; December, January, and February) under normal management conditions. Cows received a leg tag to measure daily lying time, and number of steps and standing bouts, and a neck tag to measure eating and rumination time. All cows were housed in sand-bedded freestall barns equipped with cooling systems (soakers and fans). Behavior, milk production and milk components were recorded for the first 9 wk of lactation after calving. Average temperature-humidity index (THI) was 78.2 ± 0.4 (± standard error) in the HS and 54.4 ± 0.2 in the CS. Fat-corrected milk yield was greater in the CS compared with HS during the first 5 wk of lactation. Milk protein percentage was lower in CS during the first 2 wk of lactation. In contrast with HS, milk fat percentage was greater in the CS. Compared with CS, overall, during HS cows spent less time eating, lying down, and tended to spend less time ruminating. In addition, exposure to high THI resulted in increases in standing bouts, and overall standing time in HS relative to CS. No differences in number of steps were observed between HS and CS. In summary, exposure to high THI during lactation seems to negatively affect the behavior and consequently the daily time budget of lactating Holstein cows, even under housing conditions with active cooling. A better understanding on how different seasons affect the daily time budget of lactating dairy cows may contribute to the development of more effective management strategies to decrease the negative effects of heat exposure.
Heat stress (HS) reduces production and efficiency in almost every metric of the dairy operation, and it thus compromises profitability and sustainability. If the magnitude of HS progresses, it can become lethal. Death can occur acutely or days following the heat load, even if environmental conditions have become nonstressful. Consequently, lethal heat stress (LHS) is often difficult to identify and almost always misdiagnosed. The precise mechanisms of death when dairy cows succumb to LHS has not been fully elucidated or documented, but the pathophysiology of LHS appears to be conserved among several species. The unique digestive physiology of ruminants adds additional layers of complexity that contribute to failure of multiple systems involved with LHS. Consequently, the ostensible etiology and pathogenesis of LHS described herein is extended from the physiological adaptations cows use to survive HS and pertinent pathology extrapolated from other species. The multifactorial causes of death likely involve dysfunction and imbalance of several interdependent systems as follows: (1) electrolyte dyshomeostasis, (2) unstable blood pH, (3) gastrointestinal tract hyperpermeability, (4) sepsis, (5) severe immune activation-induced inflammation, (6) disseminated intravascular hypercoagulation, (7) systemic endothelial permeability, (8) multiple organ failure, and (9) circulatory failure. Having a better understanding of the mechanisms of LHS will improve diagnosis, enable a more accurate prognosis, and provide insight into strategies aimed at preventing dairy cow mortality and morbidity.
Our primary objective was to perform a meta-analysis and meta-regression to evaluate the effects of diets supplemented with calcium salts of palm fatty acids (CSPF) compared with nonfat supplemented control diets (CON) on nutrient digestibility and production responses of lactating dairy cows. Our secondary objective was to perform a meta-analysis to evaluate whether experimental design affects production responses to supplemental CSPF. The data set was formed from 33 peer-reviewed publications with CSPF supplemented at ≤3% diet dry matter. We analyzed the interaction between experimental design (continuous vs. change-over) and treatments (CON vs. CSPF) to evaluate whether experimental design affects responses to CSPF (Meta.1). Regardless of experimental design, we evaluated the effects of CSPF compared with CON on nutrient digestibility and production responses of lactating dairy cows by meta-analysis (Meta.2) and meta-regression (Meta.3) approaches. In Meta.1, there was no interaction between treatments and experimental design for any variable. In Meta.2, compared with CON, CSPF reduced dry matter intake [DMI, 0.56 ± 0.21 kg/d (±SE)] and milk protein content (0.05 ± 0.02 g/100 g), increased neutral detergent fiber (NDF) digestibility (1.60 ± 0.57 percentage units), the yields of milk (1.53 ± 0.56 kg/d), milk fat (0.04 ± 0.02 kg/d), and 3.5% fat corrected milk (FCM, 1.28 ± 0.60 kg/d), and improved feed efficiency [energy corrected milk (ECM)/DMI, 0.08 kg/kg ± 0.03]. There was no effect of treatment for milk protein yield, milk fat content, body weight, body weight change, or body condition score. Compared with CON, CSPF reduced the yield of de novo milk fatty acids (FA) and increased the yields of mixed and preformed milk FA. In Meta.3, we observed that each 1-percentage-unit increase of CSPF in diet dry matter reduced DMI, increased NDF digestibility, tended to increase FA digestibility, increased the yields of milk, milk fat, and 3.5% FCM, reduced the content of milk protein, reduced the yield of de novo milk FA, and increased the yields of mixed and preformed milk FA. In conclusion, our results indicate no reason for the restrictive use of change-over designs in CSPF supplementation studies or meta-analysis. Feeding CSPF increased NDF digestibility, tended to increase FA digestibility, and increased the yields of milk, milk fat, and 3.5% FCM. Additionally, CSPF increased milk fat yield by increasing the yields of mixed and preformed milk FA.
In this study, the effects of rumen-protected fat (RPF) were evaluated as an energy source for partial replacement of grain feed in the diets of Merino male lambs during the hot season. Fourteen six months old Merino male lambs weighing average of 29.59 kg were randomly allocated into two groups: control diet (CON) and diets supplemented with 30 g/kg RPF. Live weight (LW), dry matter intake (DMI) and average daily gain (ADG) were recorded, and the feed conversion ratio (FCR) was then calculated. The ruminal pH, the ruminal ammonia nitrogen concentrations (NH3-N) value, the molar proportion of volatile fatty acid (VFA), blood serum as well as hematological parameters were determined and protozoa numbers were counted. While the live weight and daily gain of the lambs were not influenced by dietary treatments, DMI was increased with RPF supplementation. The ruminal pH, VFA and ruminal NH3-N concentrations were unchanged, but the protozoa numbers decreased significantly by RPF supplementation (P<0.05). RPF supplementation significantly affected some serum and hematological parameters in comparison to the control group. In conclusion, RPF may be added to concentrate mixture lamb feed at the level of 30 g/kg to enhance the diet energy density without negatively changing the animal’s performance.
Background and objectives: Heat stress (HS) is one of the environmental stressors which has significant effects on the dairy cattle industry. The biological mechanisms by which the thermal stress effects on the livestock production performance can be somewhat explained by reduced feed intake, but it is more relevant to hormonal changes, reduced rumination and absorption of nutrients, as well as increased maintenance requirements, which reduces the amount of nutrients / energy for production purpose. The objective of this study was to identify the direct and indirect effects of acute HS during the last gestation on nutrient digestibility and rumination behavior of dairy cows.
Materials and methods: Holstein dairy cows (n= 10/treatment) with similar parity and body weight (BW), were randomly assigned to one of the three following treatments during 45 d before calving: 1) Cooling and ad libitum feed intake (TN), 2) Cooling and pair-feeding (CLPF), and 3) HS and ad libitum feed intake (HS). Cows in all groups received individually the same diet. During the experiment, daily temperature and the relative humidity were recorded. During the 26-21 d and 10 to 5 d before calving, the feed intake behavior was record for 24 hours. Nutrients digestibility was measured on 26 - 21 d and 10 - 5 before calving.
Results: Heat stressed and feed restricted cows had lower feed intake. Heat stressed and food restricted cows had lower eating time significantly compare to the control group. Heat stressed cows had the lowest rumination activity. Also, the heat stressed cows had significantly lower resting time than the control group. Also, heat stress significantly reduced the DM and NDF digestibility.
Conclusion: Late gestation heat stress caused decreased feed intake. Also, nutrient digestibility of the diet negatively affected by heat stress. However, feed restriction in late gestation did not have significant effect on nutrient digestibility than the control group. In addition, heat stress reduced the rumination activity and resting time of the cows
This study was realized to evaluate the effects of a yeast-based additive complex (AC) on animal performance, heat stress behaviors, and carcass characteristics of beef steers fed in feedlot during a period of thermal heat stress. Black-hided beef steers (n = 192; initial live weight = 403 ± 24.5 kg) were used in a randomized complete block design experiment with 2 treatments; a steam flaked corn-based diet with AC (fed at 0.14 kg∙hd⁻¹∙d⁻¹) and a diet without AC (CON). Steers were stratified by live weight to 1 of 2 weight blocks and randomly allocated to an experimental treatment within block. Experimental supplementation was fed till d 75. Steers were fitted with an ear tag that recorded rumination and activity in 2-h intervals; whereas heat stress behaviors were recorded in 1-min intervals. Pen was used as the experimental unit for animal performance, carcass characteristics, and rumination, and animal was used for heat stress behaviors, while day was used as repeated measure for the analysis of heat stress behaviors and rumination. Data were analyzed using the MIXED procedure of SAS. Final live weight (LW), average daily gain (ADG), dry matter intake (DMI), and gain:feed (G:F) were not affected (P > 0.38) by treatment (d 1-76). Time spent ruminating (min/d) were not affected by AC supplementation (P ≥ 0.21). Treatment did not influence (P > 0.13) time spent panting, resting, or eating. Supplementation of AC did not impact (P ≥ 0.22) HCW, fat thickness, Longissimus area, or marbling score . Dressing percentage was decreased (P = 0.02) with AC addition (60.4% ± 0.6) compared to CON (61.0% ± 0.6) and calculated yield grade tended (P = 0.09) to increase with AC (2.51 ± 0.16) compared to CON (2.37 ± 0.16). Overall, feedlot performance, efficiency and carcass characteristics were not influenced by the supplementation of AC. Supplementing cattle exposed to thermal heat stress with AC did not impact rumination or panting behaviors.
Thermal stress can impact negatively on performance of intensively managed livestock in the southern United States and other subtropical and tropical regions of the world. Three funda- mental management practices, physical protection, genetic development and nutritional manage- ment schemes, have been proposed to alleviate partially the extent and severity of thermal stress. Focus of this paper is on i) interrelationships of thermal stress with functions involved in acqui- sition of nutrients and their metabolism, 2) considerations for provision of energy and nutrients during thermal stress and 3) potential practical management strategies to enhance animal pro- ductivity and efficiency. Discussion concentrates primarily on cattle. Acquisition of potentially absorbable nutrients and energy by the thermal-stressed animal is affected negatively by reduc- tion in dry matter intake, positively by slightly enhanced digestibility because of greater reten- tion time in the gut and, probably, negatively by reduced blood flow to and nutrient absorption from the alimentary tract. Negative influences of reduced intake and absorption of nutrients largely offset small enhancement in digestibility, resulting in less total nutrients being available to the thermal-stressed animal. Physiological adaptations to acute and(or) chronic thermal stress alter metabolism of absorbed energy substrates and nutrients. Hormones involved in adaptation to thermal stress include prolactin, growth hormone, thyroxine, glucocorticoids, antidiuretic hor- mone and aldosterone. These are either involved with nutrient partitioning and homeorhesis or with need for homeostatic regulation, potentiated by the thermal stressor. Increasing the energy density of diets fed to thermal-stressed animals by increasing concentrate to forage ratios or adding protected fat is discussed. For supplemental protein, the idea is suggested that increasing nutrient content may not always result in the most biologically and economically efficient production for a thermal-stressed animal. Water and macromineral needs, influenced heavily by demands to maintain homeostasis and homeothermy, are altered for lactating dairy cows. However, this may not be true for animals with lower turnover rates of these nutrients. A number of nutritional technologies are available to aid the thermal-stressed animal; others are not yet developed. Establishment of prediction equations for requirements of nutrients fed to livestock in different productive states during various intensities of thermal stress are needed. Forms of equations should describe the absolute nutrient needs (e.g., g.kg milk -1 -d -1 ) rather
Ten dairy cows were allocated into three groups according to milk productivity (four high, four intermediate and two dry cows, respectively). Heat production and heart rate, but not rectal temperature, were significantly different (P < 0·05) between groups. Heat production increased during feeding in the morning and in the afternoon and reached a peak 3 h later. Minimum heat production was observed in the early morning before feeding. The diurnal pattern for heart rate reflected that of heat production. These results suggest that cooling dairy cows during hot summer days is most effective at feeding time and 3 h afterwards.
Our objective was to provide a review of factors influencing heat stress in lactating dairy cows and how it affects milk production. In warmer parts of the world, during summer months in the United States, and in other temperate regions, reduced milk production resulting from heat stress counteracts tremendous genetic progress achieved in increasing milk production. Genetic progress in milk production is closely related to increased feed intake. High feed intake results in raised metabolic heat increment. High metabolic heat increment requires effective thermoregulatory mechanisms to maintain body temperature in a thermoneutral zone and in physiological homeostasis. Cows can succumb to hyperthermia if they fail to maintain thermoneutrality. Accurate measurement of when cows enter heat stress is complicated because the responses to heat stress affect not only the energy balance, but also water, sodium, potassium and chlorine metabolism. Water, sodium, potassium and chlorine are important constituents of sweat, and sweating is a major, if not the most important, thermoregulatory mechanism used to dissipate excess body heat. Due to high metabolic heat increment, and especially in the warmer months, high-producing dairy cows may enter heat stress much earlier than their lower-producing counterparts and than currently thought, or extra heat has been accommodated by physiological adaptations. Should this be the case, then strategies to reduce heat stress must be developed to enable cows to express their full genetic potential. The thermoneutral zone, heat production and heat gain, heat dissipation mechanisms, and how the lactating cow responds to heat stress are discussed.
Heat stress is detrimental to dairy production and affects numerous variables including feed intake and milk production. It is unclear, however, whether decreased milk yield is primarily due to the associated reduction in feed intake or the cumulative effects of heat stress on feed intake, metabolism, and physiology of dairy cattle. To distinguish between direct (not mediated by feed intake) and indirect (mediated by feed intake) effects of heat stress on physiological and metabolic indices, Holstein cows (n = 6) housed in thermal neutral conditions were pair-fed (PF) to match the nutrient intake of heat-stressed cows (HS; n = 6). All cows were subjected to 2 experimental periods: 1) thermal neutral and ad libitum intake for 9 d (P1) and 2) HS or PF for 9 d (P2). Heat-stress conditions were cyclical with daily temperatures ranging from 29.7 to 39.2 degrees C. During P1 and P2 all cows received i.v. challenges of epinephrine (d 6 of each period), and growth hormone releasing factor (GRF; d 7 of each period), and had circulating somatotropin (ST) profiles characterized (every 15 min for 6 h on d 8 of each period). During P2, HS cows were hyperthermic for the entire day and peak differences in rectal temperatures and respiration rates occurred in the afternoon (38.7 to 40.2 degrees C and 46 to 82 breaths/min, respectively). Heat stress decreased dry matter intake by greater than 35% and, by design, PF cows had similar reduced intakes. Heat stress and PF decreased milk yield, although the pattern and magnitude (40 and 21%, respectively) differed between treatments. The reduction in dry matter intake caused by HS accounted for only approximately 35% of the decrease in milk production. Both HS and PF cows entered into negative energy balance, but only PF cows had increased (approximately 120%) basal nonesterified fatty acid (NEFA) concentrations. Both PF and HS cows had decreased (7%) plasma glucose levels. The NEFA response to epinephrine did not differ between treatments but was increased (greater than 50%) in all cows during P2. During P2, HS (but not PF) cows had a modest reduction (16%) in plasma insulin-like growth factor-I. Neither treatment nor period had an effect on the ST response to GRF and there was little or no treatment effect on mean ST levels or pulsatility characteristics, but both HS and PF cows had reduced mean ST concentrations during P2. In summary, reduced nutrient intake accounted for just 35% of the HS-induced decrease in milk yield, and modest changes in the somatotropic axis may have contributed to a portion of the remainder. Differences in basal NEFA between PF and HS cows suggest a shift in postabsorptive metabolism and nutrient partitioning that may explain the additional reduction in milk yield in cows experiencing a thermal load.
Multiparous, lactating Holstein cows (n = 23; 120 +/- 30 d in milk, 690 +/- 67 kg of body weight) housed in climatic chambers were randomly assigned to 1 of 2 dietary treatments: a diet containing a novel yeast culture formulation (YC) for heat stress (n = 12, 10 g/d) or a control diet (n = 11). The trial length was 28 d and consisted of a 7-d thermal neutral period (TN; 18 degrees C, 20% humidity) followed by 21 d of heat stress (HS; cyclical daily temperatures ranging from 29.4 to 37.8 degrees C and 20% humidity). Cows were individually fed a total mixed ration consisting primarily of alfalfa hay and steam-flaked corn. During TN, the YC feeding had no effect on production variables or most body temperature indices. During HS, all body temperature indices increased and YC had no effect on rump surface temperature, respiration rate, or sweating rates. Cows fed YC had lower rectal temperatures at 1200 and 1800 h (40.29 vs. 40.02 degrees C and 40.35 vs. 40.12 +/- 0.07 degrees C, respectively) compared with control-fed cows. Cows fed both diets lost body weight (42 kg) during HS, but there were no differences between diets. Control-fed cows had increased dry matter intake (DMI) and milk yield (19.1 vs. 17.9 +/- 0.5 kg/d and 32.15 vs. 29.15 +/- 0.02 kg/d, respectively) compared with YC-fed cows, but intake and milk production were similar between diets when evaluated on a body weight basis. Heat stress progressively decreased DMI (29%) and milk yield, with milk production reaching a nadir (33%) in the third week. Heat stress decreased milk protein (7%) and lactose (5%) levels, but did not alter milk fat content. Heat-stressed cows were in calculated negative energy balance (-1.91 +/- 0.70 Mcal/d) and this was unaffected by diet. Independent of diet, HS decreased plasma glucose (11%), but neither diet nor HS altered basal nonesterified fatty acid levels. Heat stress increased plasma urea N concentrations (11.5 vs. 14.8 +/- 0.4 mg/dL). Despite YC-fed cows having slightly reduced body temperatures indices, feeding YC did not prevent the negative effects of HS.
The effect of feeding Ca soaps of fatty acids for 120 d from parturition on productive and reproductive performance of dairy cows was examined, together with changes in blood lipids and progesterone. Cows fed Ca soaps received 1.5 Mcal NE1 d more than controls fed isonitrogenous and equi-forage rations. Cows fed Ca soaps produced more milk and fat for 60 d, and more FCM for 90 d after calving. In these cows, BW decreased more, and reached a minimum later than controls. Plasma free fatty acids were higher until 50 d postpartum, when phospholipid, and later triglyceride, concentrations were elevated. Cows fed soaps commenced ovarian cyclicity later than controls as shown by frequency distribution of the time required to reach cyclic plasma progesterone concentrations, 2 ng/ml progesterone in plasma, or behavioral estrus. However, once cyclicity commenced, more fat-fed cows had normal cycle length (18 to 26 d) than controls. Progesterone concentrations were higher in Ca soap-fed cows in the luteal phase before AI and were higher 9 and 24 d after AI in percent that conceived. Conception rate was higher in cows fed Ca soaps for 2nd to 4th AI, a higher proportion of cows were pregnant at 150 d after calving and number of open days was reduced. Feeding Ca soaps of fatty acids resulted in higher production at the expense of body reserves close to calving, and subsequently enhanced lipid concentrations in plasma. Higher progesterone production was accompanied by increased pregnancy rate and reduced open days.
Physiological state of dairy animals is a predisposing factor in environmental influences on animal health. Critical phases of life cycle include neonatal period, postpubertal reproduction, and lactation. Primary effect of environment in neonatal period is increased disease incidence associated with reduced immunoglobulin content in plasma of calves. Cold stress has little effect on reproduction; in contrast, heat stress reduces libido, fertility, and embryonic survival in cattle. Heat stress in late gestation reduces fetal growth and alters endocrine status of the dam. Carryover effects of heat stress during late gestation on postpartum lactation and reproduction also are detectable. Heat stress of lactating cattle results in dramatic reductions in roughage intake and rumination. Decreases in roughage intake contribute to decreased volatile fatty acid production and may contribute to alteration in ratio of acetate/propionate. Rumen pH also declines during thermal stress. Electrolyte concentrations, in particular sodium and potassium, also are reduced in rumen fluid of heat stressed cattle. The decrease in sodium and potassium are related to increases in loss of urinary sodium and loss of skin potassium as well as decline in plasma aldosterone and increase in plasma prolactin. Reduction in thyroxine, growth hormone, and glucocorticoid concentrations in chronically heat stressed cattle appear to be related to decreases in basal metabolism.
Cows that were subjected to hot environmental temperatures yielded less milk (3.1 kg/d) on a diet high in CP (18.4%) and of medium degradability (65%) than on diets high in CP of low degradability (59%) or medium in CP (16.1%). The high CP diets were associated with decreased DMI and higher water intake, ruminal NH4, and blood urea. Negative effects on yield from the high CP, medium degradability diet were not observed at moderate temperatures. Evaporative cooling of cows in hot weather resulted in a greater milk yield response to low versus medium rumen-undegradabale protein diets than for uncooled cows. Evaporative cooling of cows also affected response to protein quality. For cooled cows, high Lys diet (soybean, fish, and blood meals) increased milk yield 14% over that with low Lys diet (corn gluten meal), but, for uncooled cows, a high Lys diet only increased yield by 9%. Percentage of CP, degradability, and protein quality had no effect on body temperatures or respiration rates of lactating cows. Some, but not other, reports showed that supplementation of 2 to 2.5% fat to diets fed under hot summer conditions resulted in less yield response than when fat was added at moderate temperatures. In several studies, fungal cultures (3 to 5 g/d) in the diet decreased body temperatures and respiration rates in hot, but not cool, weather. Increased milk yields and cellulose digestibility also resulted from dietary fungal cultures in some, but not all, trials. The mechanism of action exerted by fungal cultures on body temperature and respiration rate is unclear.
Twelve lactating, multiparous Holstein cows were used to evaluate the effects of silage chop length and proportion of long hay in low and adequate forage fiber diets on chewing activities and productivity of cows fed barley-based concentrates. Diets were designed with two forage:concentrate ratios (low forage fiber, 35:65; adequate forage fiber, 65:35), combined with two theoretical chop lengths of alfalfa silage (fine, 5 mm; coarse, 10 mm), and three proportions of long-stemmed alfalfa hay (0, 10, and 20% of DMI). Increasing the chop length of silage in low forage fiber diets did not affect DMI but increased FCM; in adequate forage fiber diets, it decreased DMI and FCM. Addition of hay to silage diets increased DMI, but not FCM yield. Increasing silage chop length in diets formulated below the recommended minimal amount of NDF from forage promoted rumination and increased milk production while maintaining milk fat content and DMI. Addition of a small amount of hay to low forage fiber diets was less effective than increased particle length of silage. In adequate forage fiber diets, finely chopped silage can be used effectively.
Eight Holstein cows (mean = 52 DIM) were used in a replicated Latin square design (28-d periods) to determine the effects of source and amount of dietary energy on hepatic lipid metabolism. Diets were 1) low concentrate without supplemental fat (1.6 Mcal of NEI/kg), 2) low concentrate with supplemental fat (1.7 Mcal/kg), 3) high concentrate without supplemental fat (1.7 Mcal/kg), and 4) high concentrate with supplemental fat (1.8 Mcal/kg). Intakes of DM and digestible energy were greatest for diets 2 and 3. Milk production, efficiency, and milk CP production were not different among diets. Milk fat percentage and production were increased by supplemental fat and decreased by high concentrate. Contents of CP, true protein, and casein in milk were decreased by supplemental fat and increased by high concentrate. Digestibility of fatty acids was decreased by either supplemental fat or high concentrate. Concentrations of NEFA and somatotropin in plasma were increased, and concentration of IGF-I was decreased, by supplemental fat; NEFA, BHBA, and IGF-I were decreased by high concentrate. In vitro rates of peroxisomal beta-oxidation and esterification of palmitate and concentrations of total lipid and triglycerides in liver were not different among diets, but glycogen content was increased by high concentrate. The rate of total beta-oxidation of palmitate in liver slices tended to be increased by supplemental fat; total metabolism of palmitate was increased by supplemental fat and tended to be increased by high concentrate. Supplemental fat may affect hepatic lipid metabolism in dairy cows; effects of dietary fat during the periparturient period deserve investigation.
The southeastern United States is characterized as humid subtropical and is subject to extended periods of high ambient temperature and relative humidity. Because the primary nonevaporative means of cooling for the cow (radiation, conduction, convection) become less effective with rising ambient temperature, the cow becomes increasingly reliant upon evaporative cooling in the form of sweating and panting. High relative humidity compromises evaporative cooling, so that under hot, humid conditions common to the Southeast in summer the dairy cow cannot dissipate sufficient body heat to prevent a rise in body temperature. Increasing air temperature, temperature-humidity index and rising rectal temperature above critical thresholds are related to decreased dry matter intake (DMI) and milk yield and to reduced efficiency of milk yield. Modifications including shade, barns which enhance passive ventilation, and the addition of fans and sprinklers increase body heat loss, lowering body temperature and improving DMI. New technologies including tunnel ventilation are being investigated to determine if they offer cooling advantages. Genetic selection for heat tolerance may be possible, but continued selection for greater performance in the absence of consideration for heat tolerance will result in greater susceptibility to heat stress. The nutritional needs of the cow change during heat stress, and ration reformulation to account for decreased DMI, the need to increase nutrient density, changing nutrient requirements, avoiding nutrient excesses and maintenance of normal rumen function is necessary. Maintaining cow performance in hot, humid climatic conditions in the future will likely require improved cooling capability, continued advances in nutritional formulation, and the need for genetic advancement which includes selection for heat tolerance or the identification of genetic traits which enhance heat tolerance.
Meteorological data (1993 to 2004) from 2 public weather stations in Phoenix, Arizona, and Athens, Georgia, were analyzed with test day milk yield data from herds near weather stations to identify the most appropriate temperature-humidity index (THI) to measure losses in milk production due to heat stress in the semiarid climate of Arizona and the humid climate of Georgia. Seven THI with different weightings of dry bulb temperature and humidity were compared. Test-day data were analyzed using 2 models to determine threshold of heat stress and rate of decline of milk production associated with a specific THI. Differences in thresholds of heat stress were found among indices and between regions. Indices with higher weights on humidity were best in the humid climate, whereas indices with larger weights on temperature were the best indicators of heat stress in the semiarid climate. Humidity was the limiting factor of heat stress in humid climates, whereas dry bulb temperature was the limiting factor of heat stress in dry climates.
The cellular heat stress (HS) response is one component of the acute systemic response to HS. Gene networks within and across cells and tissues respond to environmental heat loads above the thermoneutral zone with both intra- and extracellular signals that coordinate cellular and whole-animal metabolism. Activation of these systems appears to be initiated at skin surface temperatures exceeding 35 degrees C as animals begin to store heat and rapidly increase evaporative heat loss (EVHL) mechanisms. Gene expression changes include 1) activation of heat shock transcription factor 1 (HSF1); 2) increased expression of heat shock proteins (HSP) and decreased expression and synthesis of other proteins; 3) increased glucose and amino acid oxidation and reduced fatty acid metabolism; 4) endocrine system activation of the stress response; and 5) immune system activation via extracellular secretion of HSP. If the stress persists, these gene expression changes lead to an altered physiological state referred to as "acclimation," a process largely controlled by the endocrine system. In the acclimated state, metabolism is adjusted to minimize detrimental effects of increased thermal heat load. The role of secreted HSP in feedback regulation of the immune and endocrine system has not yet been investigated. The variation in EVHL among animals and the central role that HSF1 has in coordinating thermal tolerance suggest that there is opportunity to improve thermal tolerance via gene manipulation. Determining the basis for altered energy metabolism during thermal stress will lead to opportunities for improved animal performance via altered nutritional management.
Three experiments investigated how for- ages of different chemical composition affect rumination time of cattle. Three single reversal designs used four dairy heifers and two dairy steers in Experi- ment I and four dairy heifers in Experi- ments II and III. The rumination time produced by feeding a single 5-kg meal of test forage was measured with jaw mo- tion recordings. In Experiment I the test meal was fed after 2 days of fasting; fol- lowing the test meal no more was offered for an additional 2 days. In Experiments II and III only alfalfa pellets were offered during the 2 days before and after the test meal, at the rate of 2.27 kg per head per day. In Experiment I the animals which were fed straw ruminated 578 min- utes following the test meal; the animals fed an excellent quality hay ruminated a shorter (P < .05) time of 369 minutes. Experiment II compared a good-quality mixed second-cutting hay with straw. The straw produced 539 minutes' rumination time, and the second-cutting hay produced a shorter (P < .05) time of 387 minutes. In Experiment III good-quality orchard- grass produced 258 minutes' rumination time; poor-quality orchardgrass produced a longer (P < .05) time of 449 minutes. The correlation between rumination time and cell wall constituent (CWC) content was 0.94.
65201 Summary Digestibility and ingesta rate of passage were determined with Holstein steers fed chopped tall fescue "Festuca arundinacea Schreb,/alfalfa "Medicago sativa" and orchardgrass "Dactylis glomerata" hay in 18 and 32 C temperatures. Steers fed alfalfa ate more and drank more water than steers fed orchardgrass or fescue; alfalfa was more digestible. Digestible dry matter (DDM), water intake and mean reten- tion time (MRT) increased as temperature increased. Maximum excretion rate (MER) and MRT, determined by using 144Ce. were not related to voluntary forage intake. The data indicate that if gut Fill is a regulating mechanism in the intake of forages as suspected, then MRT and MER are not good estimates of gut fill.
Coupling repeated wetting of the coat and forced ventilation is most efficient in removing heat stress in more humid climates. The procedure was initiated approximately 24 yr ago and is widely used, but the impact of air velocity on the efficiency of heat stress relief has not been examined. This study examined the feasibility of using surface temperature for real-time estimation of heat stress relief. It was carried out in midsummer in Israel on 6 mature lactating Holsteins. A 15 x 15 cm area on the right side of the body was thoroughly wetted. Hair surface and skin temperature on the wetted area and adjacent dry area were measured at 1-min intervals for 15 min while air movement was less than 0.1 m/s, and the sequence was repeated with air velocities of 0.5 to 3 m/s perpendicular to the body surface. Because the cooled surface was small, the response to cooling was local. In 3 animals, the whole left side of the body also was wetted and exposed to forced ventilation (1.5 m/s) to combine local cooling with larger body surface cooling. The air temperature was 29.5 +/- 0.05 degrees C, and the relative humidity was 56.7 +/- 0.2%. Rectal temperature and respiratory frequency indicated minor heat stress. Mean wet hair surface temperature (Thw) and wet skin temperature were 2.1 and 1.5 degrees C lower than the respective dry hair surface temperature (Thd) and dry skin temperature. At an air velocity of 0.5 m/s, Thw was practically identical to that in still air and to Thd. At greater air velocities, Thw decreased immediately after wetting, and minimal values were reached within 1 min, were maintained for 6 to 7 min after wetting, and reached 95% of the mean Thd value by 8 and 11 min after wetting at 1 and 2 m/s, respectively. Wetting the coat had the potential to reduce Thd temperature by 10 to 11 degrees C. The relatively small difference between Thd and Thw probably is due to heat flow from the body. The latter was estimated by comparing enthalpies at Thd, at Thw, and in the wet bulb temperature predicted for Thd. Predicted heat loss rates were 736 and 1,012 W/m(2) at air velocities of 1 and 2 m/s, respectively, compared with 164 W/m(2) predicted for the dry surface from the thermal balance model. Increasing heat loss from the left side reduced wet surface temperatures on right side, indicating that larger body surface cooling reduced heat flow to the skin on the right body surface. Heat extraction from the wet body surface is thus reduced by large body surface cooling and depends on the thermal state. The efficiency of heat stress relief may be detected by surface temperature monitoring and may be improved by adjusting the interval between wettings to the changes in surface temperature.
The environmental profile of central Arizona is quantitatively described using meteorological data between 1971 and 1986. Utilizing ambient temperature criteria of hours per day less than 21 degrees C, between 21 and 27 degrees C, and more than 27 degrees C, the environmental profile of central Arizona consists of varying levels of thermoneutral and heat stress periods. Milk production data from two commercial dairy farms from March 1990 to February 1991 were used to evaluate the seasonal effects identified in the environmental profile. Overall, milk production is lower during heat stress compared to thermoneutral periods. During heat stress, the cool period of hours per day with temperature less than 21 degrees C provides a margin of safety to reduce the effects of heat stress on decreased milk production. Using minimum, mean and maximum ambient temperatures, the upper critical temperatures for milk production are 21, 27 and 32 degrees C, respectively. Using the temperature-humidity index as the thermal environment indicator, the critical values for minimum, mean and maximum THI are 64, 72 and 76, respectively.
Effects of supplemental prilled long-chain fatty acids on lactation performance during heat stress were examined using eight multiparous Holstein cows in a replicated 4 x 4 Latin square design with 15-d periods. Cows were ruminally cannulated and were assigned randomly to one of four treatments in a 2 x 2 factorial arrangement of treatments. Factors were 0 or 5% supplemental fat and thermoneutral or heat stress conditions. Cows were housed in environmental chambers with thermoneutral conditions of 20.5 degrees C and 38% relative humidity for 24 h/d or heat stress conditions of 31.8 degrees C and 56% relative humidity for 14 h/d and 25.9 degrees C with 56% relative humidity for 10 h/d. Isonitrogenous diets (17% CP) containing 50% alfalfa silage and 50% concentrate were offered for ad libitum intake. Diets contained 1.64 or 1.83 Mcal NEL/kg DM. No diet by environment interactions were significant. Milk fat percentage (3.46 vs. 3.15%) and 3.5% FCM (31.5 vs. 29.2 kg/d) were higher for cows fed 5 vs. 0% fat. Dry matter intake, milk yield, and milk protein percentage did not differ between diets. Heat stress decreased DMI, milk yield, 3.5% FCM, and milk protein percentage but did not affect milk fat percentage. Results suggest that supplemental fat at 5% of diet DM enhances lactation performance similarly under thermoneutral and heat stress conditions.
Improved reproductive performance and reduced incidence of metabolic disorders have been postulated to be benefits of feeding supplemental fat to dairy cows. Increased plasma nonesterified fatty acid concentrations during fat supplementation may result from incomplete tissue uptake of fatty acids after lipoprotein lipase hydrolysis of very-low-density lipoprotein triglyceride; however, evidence suggests that net adipose tissue triglyceride hydrolysis may be increased during fat supplementation. Plasma 3-OH-butyrate concentrations remain relatively constant during fat supplementation but may have a tendency to be reduced if fat is supplemented to cows having relatively high basal plasma 3-OH-butyrate concentrations. Because plasma ketone levels usually increase when nonesterified fatty acid concentrations are elevated, it is hypothesized that potential antiketogenic effects of added fat are due to a glucose sparing effect. Supplemental fat does not seem to reduce hepatic lipid infiltration near the time of calving. Potential mechanisms by which supplemental fat may improve reproductive performance include stimulation of prostaglandin F2 a synthesis and secretion and enhanced utilization of blood cholesterol for progesterone synthesis. Days postpartum until first ovulation and luteal function of dairy cattle have been related to energy balance during the first 3 wk postpartum. Energy balance data for early lactation cows fed supplemental fat are not plentiful; however, slight but statistically nonsignificant increases have been observed when feeding fat. Cows fed supplemental fat that experience improved energy balance may begin to cycle sooner because of enhanced follicular growth and development. Applied studies examining the effects of supplemental fat on reproductive performance have provided inconsistent results.
Dissociation of 5% solutions of calcium soaps of soya, tallow, stearic acid, and palm fatty acid distillate was studied by titration with 1 N HCl. Release of calcium ions was directly correlated with decrease in pH value. Estimated pKa values were 5.6, 4.6, 4.5, and 4.5 for calcium soaps of soya, palm fatty acid distillate, tallow, and stearic acid, respectively. Dissociation of 5% solutions in acetate buffer at pH values of 5.0, 5.5, 6.0, and 6.5 was measured in terms of release of soluble calcium. Dissociation was maximum at pH 5.0, minimum at pH 6.5, and dependent on unsaturation of fatty acids in the soaps. Soluble calcium in the acetate-buffered rumen fluid was higher than predicted from pKa of calcium soaps, due to formation of soluble calcium acetate; however, the relative patterns were similar to their pKa values. Unsaturated soaps are less satisfactory for maintaining normal rumen function, because dissociation is relatively higher. Calcium soaps of palm fatty acid distillate were satisfactorily stable to pH 5.5.
Control, prilled fat (5% of ration DM), niacin (12 g/d), or fat and niacin treatments were fed to 39 Holstein cows beginning 17 d prior to expected calving through 15 wk postpartum to determine effects on hepatic lipid content, plasma ketone concentration, and lactation performance. Cows were blocked according to season of calving (cool = November 1 through April 1; warm = April 2 through August 1). Fat supplementation tended to increase milk yield but only for cows that calved in the warm season. Milk composition was not affected by treatments. Fat supplementation did not decrease BW loss in early lactation but increased rate of BW gain af ter 8 wk postpartum. Dry matter intake and glucose, nonesterified fatty acid, and beta-hydroxybutyrate concentrations in plasma were not different among treatments. Fat and niacin supplementation tended to increase hepatic total lipid and triglyceride content. Between 17 d prior to expected calving and 1 to 2 d postpartum, hepatic lipid content increased approximately 2-fold and triglyceride content increased 6- to 10-fold. Hepatic lipid and triglyceride contents were greater postpartum during the warm season than the cool season and were greater at 5 wk than at freshening during the warm season but lower at 5 wk than at freshening during the cool season. The cause of the dramatic increase in hepatic lipid and triglyceride content prepartum is unknown.
Upper limit of thermal stability and subsequent rise of thermoregulatory functions as affected by forced ventilation were examined. Rectal temperature, respiratory frequency, ear skin temperature, body weight, and milk yield were recorded biweekly July to March over 2 yr for 170 Israeli-Holstein cows (305-day milk yield 9000 kg/cow) at air temperatures 10 to 36 degrees C. Cows were in an open shelter. One side was force ventilated over 2.5 m along the stanchions (air velocity 1.5 to 3 m/s) from 0500 to 2200 h. Control side mean air velocity was .5 m/s. Within the 10 to 24 degrees C range, rectal temperature was not affected by air temperature or forced ventilation but increased by .02 degrees C/kg fat-corrected milk in animals producing above 24 kg/day. Between 26 and 36 degrees C rectal temperature increased with air temperature in both groups; rate of rise was halved by forced ventilation. In this range of air temperature, rectal temperature increased with rising milk yield, as in the lower air temperature range, in both high-producing and lower-producing cows in forced ventilation. Body weight or parity did not have significant effects. Mean ear skin temperature was higher for control animals, but its rate of increase with air temperature was similar in both groups. Forced ventilation reduced mean respiratory rate. An upper critical temperature is 25 to 26 degrees C and is independent of milk yield or acclimatizational state of cows exposed to the natural sequence of climate.
1. Previous publications by the author and his colleagues have provided extensive records, and additional ruminating behaviour of cows receiving a wide range of diets. These recoreds, and additional unpublished records, have been used to justify a proposed index of the physical property of fibrousness, or roughage, in diets for ruminants.
2. It is proposed that the total time spent by ruminants in chewing their food, during eating and during ruminating, should be the basis of the basis of the roughage index
3. Experssion of the roughage index as total time spent chewing per kg dietary dry matter largely eliminates differences resulting from variation in the amount of food consumed, and differences resulting from the time of access to the food.
4. Examples of the proposed roughasge index are given. The values range from 145 to 191 min/Kg dry matter for oat straw ot under 20 min/kg dry matter for diets of concentrates or of finely ground herbages; hays and silages tend to fall in the region of 90–110 min/kg dry matter. Values for the indx increase with dietary proportaions of hay or straw.
Two Latin squares balanced for carry-on effects were used for evaluation of produc- tive performance of 12 Holstein cows fed high levels of fat under environmental tem- peratures: cool 15-24 C and hot 32.2 C, 60% relative humidity. The cows were fed 1.25 kg alfalfa-grass hay per 100 kg body weight and one Of three concentrates: con- trol (without added lipids), oil (10% soy- bean oil), or fat (10% hydrogenated veg- etable fat, iodine value 48) replacing corn on a weight basis. Elevated temperature resulted in a marked depression in yield of milk and milk fat, SNF, and protein, of body weight, feed intake, rumen VFA, acetic :propionic ratio, and gross efficiency ; water intake and rectal temperature increased. Significant ration effects were observed only in the ease of FC!V( production, where the oil-fed cows excelled. Environmental effects were inde- pendent of ration effects, except in water intake, tureen total VFA, and acetic acid levels, where interactions were noted. Sig- nificant period effects from repeated ex- posures to heat stress were noted only in FCM yield, water consumption, and rumen propionate. The drastic environmental stress imposed in this study served to mask many of the anticipated ration effects.
Effects of dietary fat on dairy cows are reviewed. Dietary fat did not affect gain in BW or body condition score after peak lactation but tended to increase BW loss during early lactation and body fat deposition in growing cattle. Dietary fat decreased de novo fatty acid synthesis in adipose tissue. Basal FFA release from adipose tissue in vitro and beta-adrenergic lipolytic responses were increased by protected polyunsaturated fatty acids. Dietary fat increased body fat in growing pigs and decreased BW loss in lactating sows. Dietary fat decreased de novo fatty acid synthesis and basal glycerol release in adipose tissue and tended to increase simultaneously beta-adrenergic lipolytic responses to increased membrane fluidity. Dietary fat increased body fat in rats. Polyunsaturated fatty acids were sometimes less efficient than saturated ones in increasing body fat. Lipoprotein lipase activity in adipose tissue generally decreased. Hepatic fatty acid synthesis was decreased sharply by polyunsaturated fatty acids, and adipose tissue response was less important. beta-Adrenergic-stimulated lipolysis decreased, and fatty acid esterification increased, particularly from saturated fatty acids. A trend toward insulin resistance, which was more marked with saturated fatty acids, occurred in adipose tissue.