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Effects of Tasco in Alleviation of Heat Stress in Beef Cattle
Abstract
A study was conducted to evaluate the influence of Ascophyllum nodosum (Tasco) on rectal temperature, respiration rates, and in situ NDF disappearance in cattle exposed to elevated ambient temperature. Twenty-four Angus crossbred steers (average BW = 300.6 kg) were randomly assigned to treatments using a 2 × 2 factorial arrangement: 1% Tasco vs. no Tasco (control), and thermoneutral (TN) vs. heat load (HL) conditions. Three steers in each room were assigned to the Tasco vs. control treatment. In period 1 (10 d), steers were acclimated to chambers at TN (19°C) conditions. Subsequently, for periods 2 and 3, HL was maintained at a daytime high of 36°C and a nighttime low of 19 and 31°C, respectively. For period 4, temperature conditions (TN and HL treatments) were reversed and period 2 HL conditions were imposed. In periods 2 (P < 0.09) and 4 (P < 0.05), Tasco lowered DMI. In period 2, the control steers had greater (P < 0.0001) differences between maximum and minimum rectal temperatures than steers in the Tasco treatment; this difference occurred between d 4 and 8 for the HL group. In periods 2 and 3, the maximum and minimum differences in respiration rate values were greater (P < 0.05) under HL conditions for the Tasco vs. control treatment. In period 4, the maximum respiration rate response to HL tended to be greater (P = 0.07) under HL conditions for the control vs. Tasco treatment. In period 2, a trend existed for steers in the Tasco treatment to have a greater (P < 0.1) rate of in situ NDF disappearance than control steers. In conclusion, Tasco appeared to reduce rectal temperature for 3 to 4 d.
... Seaweeds are valuable alternative feeds for livestock, mostly as sources of valuable nutricines, notably chelated micro-minerals, the availability of which is higher than that of inorganic ones; complex carbohydrates with prebiotic activities; and pigments and polyunsaturated fatty acids beneficial to consumer health (Evans and Critchley, 2014;CEVA, 2005). Soluble Ascophyllum nodosum extracts obtained from alkaline hydrolysis are used as feed additives (Allen et al., 2001a;Allen et al., 2001b;Williams et al., 2009). Seaweeds are used as binding agents in shrimp feeds (CEVA, 2005). ...
... This latter effect may be due to the presence of sodium chloride and potassium gluconate in A. nodosum (Archer et al., 2008). However, beneficial effects have not always been observed with transportstressed animals and also did not last more than 3-4 days in cattle (Pompeu et al., 2011;Williams et al., 2009;Galipalli et al., 2004b;Carter et al., 2000). No alleviating effects on body weight losses or blood metabolite levels were shown in goats (Kannan et al., 2007b). ...
... In steers, A. nodosum meal increased the slowly degraded protein fraction and protein degradability, and was more beneficial to forage digestibility when supplementing low-quality forage diets (Leupp et al., 2005). An increase in neutral detergent fibre digestibility by the meal has also been reported (Williams et al., 2009). In feedlot cattle and lambs, A. nodosum meal supplemented at 2% for 2 weeks at the beginning of the feedlot period maximized carcass performance with no detrimental effect on performance and resulted in a prolonged shelf life of carcass (Anderson et al., 2006;Tavasoli et al., 2009). ...
Seaweeds are macroalgae, which generally reside in the littoral zone and can be of many different shapes, sizes, colours and composition. They include brown algae (Phaeophyceae), red algae (Rhodophyceae) and green algae (Chlorophyceae). Seaweeds have a long history of use as livestock feed. They have a highly variable composition, depending on the species, time of collection and habitat, and on external conditions such as water temperature, light intensity and nutrient concentration in water. They may contain non-protein nitrogen, resulting in an overestimation of their protein content, and nitrogen-to-protein conversion factors lower than 6.25, normally used for feed ingredients, have been advocated. They contain considerable amount of water. Most essential amino acids are deficient in seaweeds except the sulphur containing amino acids. Seaweeds concentrate minerals from seawater and contain 10-20 times the minerals of land plants. They contain only small amounts of lipids (1-5%), but majority of those lipids are polyunsaturated n-3 and n-6 fatty acids. Brown seaweeds have been more studied and are more exploited than other algae types for their use in animal feeding because of their large size and ease of harvesting. Brown algae are of lesser nutritional value than red and green algae, due to their lower protein content (up to approx. 14%) and higher mineral content; however brown algae contain a number of bioactive compounds. Red seaweeds are rich in crude protein (up to 50%) and green seaweeds also contain good protein content (up to 30%). Seaweeds contain a number of complex carbohydrates and polysaccharides. Brown algae contain alginates, sulphated fucose-containing polymers and laminarin; red algae contain agars, carrageenans, xylans, sulphated galactans and porphyrans; and green algae contain xylans and sulphated galactans. In ruminants, step-wise increase in the levels of seaweeds in the diet may enable rumen microbes to adapt and thus enhance energy availability from these complex carbohydrates. In monogastrics, those polysaccharides may impact the nutritional value but the addition of enzyme cocktails might help. In vivo studies on ruminants, pigs, poultry and rabbits reveal that some seaweeds have the potential to contribute to the protein and energy requirements of livestock, while others contain a number of bioactive compounds, which could be used as prebiotic for enhancing production and health status of both monogastric and ruminant livestock. Seaweeds tend to accumulate heavy metals (arsenic), iodine and other minerals, and feeding such seaweeds could deteriorate animal and human health. Regular monitoring of minerals in seaweeds would prevent toxic and other undesirable situations. © 2015 Food and Agriculture Organization of the United Nations.
... Although no feed additives have effectively reduced heat stress, some evidence exists that brown seaweed (Ascophyllum nodosum) may decrease core body temperature (T core ) for the short term (Spiers et al., 2004;Archer et al., 2007) and improve immune function and antioxidant capacity during heat stress, without affecting performance (Ruperez et al., 2002;Saker et al., 2004;Okab, 2007). Furthermore, it has been shown that brown seaweed fed at 1% of diet DM had a short-term effect in reducing T core of beef steers exposed to heat stress (Spiers et al., 2004;Williams et al., 2009). There are controversy reports concerning effects of seaweeds on the performance of livestock. ...
... In contrast, Kellogg et al. (2006) found that brown seaweed supplemented at 0.25% of diet increased milk production of cows during heat stress. While, Williams et al. (2009) reported that dietary supplementation of brown seaweed to steers at 1% DM had lowered DMI. However, other species of seaweed have been observed to increase feed intake and body weight gain (Al-Shorepy et al., 2001;Turner et al., 2002). ...
... In contrast, lambs fed 2% brown seaweed and exposed to T a reaching 32.0°C, during transportation in a trailer, had lower maximum and average ear canal temperatures (Archer et al., 2007); however, the lambs in that study were exposed to two stressors (heat and transportation). Similar to the finding of the present study, reduction of respiratory rate due to seaweed feeding has also been reported in beef steers (Spiers et al., 2004;Williams et al., 2009). In contrast, dietary supplementation of seaweed had no effect on respiratory rate for cows during the summer season (Cvetkovic et al., 2005;Pompeu et al., 2011). ...
Several environmental and nutritional management approaches have been used to mitigate heat stress and improve performance of farm animals in semi-arid and arid regions. The present study was designed with the intention to alleviate the negative effects of heat stress and to promote the performance of growing lambs reared under hot environmental conditions. The study was conducted on 18 male Naimey lambs with average body weight of 22.78±0.49 kg, and 4-5 months old. The animals were randomly divided into 3 equal groups (A, B and C), and fed diets containing different concentrations of seaweed (Ulva lactuca) for 90 days. Group A served as control and was offered diet containing 0.0% seaweed. Groups B and C served as treated groups and were offered diets containing 3.0 and 5.0% seaweed, respectively. Dietary inclusion of seaweed to the diet of growing lambs exposed to heat stress (max Ta 43.9οC, max RH 81.1%, max THI 84.6) neither influenced (P>0.05) the thermo-physiological parameters (rectal and skin temperatures), nor affected (P>0.05) the performance parameters (feed intake, body weight gain, feed conversion efficiency). Furthermore, dietary seaweed supplementation did not alter (P>0.05) blood constituents or blood antioxidant capacity. However, dietary seaweed supplementation significantly (P<0.05) reduced respiratory rate, and increased serum potassium concentration. Based on the data of the present study, seaweed (Ulva lactuca) supplementation to the diets of growing lambs reared under heat stress conditions did not show any indication of promoting their production performance or heat tolerance.
... Further, in developing countries where lack of cattle handling equipment means administration of medication is difficult, high-quality MNBs provide a convenient form of delivering some anthelmintics [20,21]. In addition to anthelmintics, urea and GHGe reducing agents, there has been considerable interest in the use of red seaweed, and in particular Asparagopsis taxiformis to increase production of cattle and to reduce GHGe [41][42][43][44]. Several different seaweeds have been fed to cattle and include brown seaweeds Ascophyllum nodosum, and Saragssum wightii, with a commercial product developed based on A. nodosum [43]. ...
... In addition to anthelmintics, urea and GHGe reducing agents, there has been considerable interest in the use of red seaweed, and in particular Asparagopsis taxiformis to increase production of cattle and to reduce GHGe [41][42][43][44]. Several different seaweeds have been fed to cattle and include brown seaweeds Ascophyllum nodosum, and Saragssum wightii, with a commercial product developed based on A. nodosum [43]. A recent meta-analysis on the limited data available on dietary supplementation of cattle with seaweed, indicates a significant and substantial reduction in methane yield despite marked heterogeneity in the results, with one comparison claiming methane yield was reduced by 97%. ...
Large ruminant production in developing countries is inefficient with low growth rates and likely high greenhouse gas emissions per unit of meat or milk produced. Trials conducted in Lao PDR from 2017 to 2020, studied ad libitum supplementation for 12 weeks with 20 kg high-quality molasses nutrient blocks (Four Seasons Pty Ltd., Brisbane, Australia), that were either non-medicated; fenbendazole-medicated (Panacur100®, Coopers Australia, 5 g/kg); triclabendazole-medicated (Fasinex®, Novartis Australia, 5 g/kg or 10 g/kg, respectively); or formulated with urea (8% or 10% urea, respectively). Average daily gains were determined for access to all molasses blocks and compared with access to control blocks, no supplementation, or previously determined free-grazing baseline average daily gains (55–84 g in cattle; 92–106 g in buffalo). Productivity was significantly improved following access to all molasses blocks. Average daily gains following access to 8% urea and control blocks were calculated for three age cohorts of cattle: young calves
... Brown seaweed extract supplementation has been reported to reduce rectal temperatures when beef cattle were exposed to elevated ambient temperatures (Williams et al. 2009). A similar effect was noticed by Pompeu et al. (2011) in dairy cattle fed a BSW extract supplement, indicating that seaweed supplementation helps animals cope with heat stress. ...
... Packed cell volume is not influenced by BSW supplementation in goats, although there is an indication that BSW-treated goats can have lower PCV than control goats when measured immediately after a 6-h transportation (Galipalli 2004). There is evidence that BSW supplementation can help ruminants better regulate body temperatures and cope with heat stress (Williams et al. 2009;Pompeu et al. 2011); however, BSW does not seem to have a significant effect on reducing body dehydration and shrinkage. ...
In the last century, nearly all compounds of medicinal value were derived from naturally occurring compounds found in plants, bacteria, and fungi. Yet even today several interesting plant species with potential medicinal value remain underutilized and neglected. In a changing world, where unfavorable climatic and anthropogenic scenarios threaten natural vegetation across the globe, there is an urgent need to identify and investigate underutilized medicinal plants. Also, the utilization of such species should go hand in hand with their conservation. With the island territory of Puerto Rico as an example, we present a case for such underutilized medicinal plant species which could end up being the source of the next wonder drug for humanity. We also emphasize the need for sustainable utilization of such resources to go hand in hand with their conservation.
... (Makkar et al., 2016). Similarly, Williams et al. (2009) observed an enhanced rate of NDF degradability in the in situ experiments with cannulated steers treated with A. nodosum. Ushakova et al. (2006) suggested that these effects might be linked to modifications in the diversity of the ruminal microbe community in cattle. ...
... Ascophyllum nodosum alkaline hydrolysis extracts are used as feed additives. (Allen et al., 2001;Williams et al., 2009). Seaweeds act as binders in aquatic feeds. ...
Aquaculture is an essential sector in Malaysian fisheries and plays a significant role in the national economy. Organic pollution, opportunistic microorganisms in aquaculture farms, and international contamination of feed by mycotoxigenic fungi are serious issues. Lactic acid bacteria are a biological method for maintaining and restoring the normal physiological state and increasing productivity. However, research into the effects of inoculated seaweed silage with lactic acid bacteria inoculants is limited and has been conducted under various experimental conditions. The aim of this review is the potential of using lactic acid bacteria as an inoculant for seaweed silage for the development of sustainable aquaculture. According to the microbiological point of view, the results in this area are weak, and limited information is available. Due to its high nutritional content, seaweed silage is a promising feed ingredient and is gaining popularity as an alternative feed. Seaweeds contain valuable metabolites such as polyunsaturated fatty acids, carotenoids, phlorotannins, carrageenan, alginate pigments, agar, and minerals (manganese, iodine, calcium, iron, selenium, sodium, zinc) are natural antibiotic source in aquaculture feed. In conclusion, increasing the use of effective lactic acid bacteria as an inoculant in aquaculture feed can make the aquacultural sector more productive, safer, and friendly to human and environment then contributing to the long-term development of aquaculture.
... However, in this regard, Salama et al. (25) revealed that dietary Zn increased the digestibility of dry matter (D.M.), organic matter and crude protein (C.P.) for goats. Previous studies used several methods for heat stress alleviation and improved farm animals' performance, including feeding strategies and management (35). However, there was lake information about using zinc supplement to reduce heat stress effect on performance and behavior of Iraqi native lamb. ...
The aim of the current study was to determine whether adding zinc to water will improve lamb performance and behavior during a hot climate. In this experiment, twenty seven lambs were housed indoor in individual pens (1.50 x 1.30m). Zinc was added to the fresh drinking water in three different levels namely T1 (0 mg Zn/day), T2 (36 mg Zn/day) and T3 (72 mg Zn/day). Rumination (m/h), feeding time (m/h), number of visiting feeds (n/h), standing time (m/h), lying time (m/h) and standing bouts (n/h) were recorded three times a day by visual observation. Dry matter intake (kg/d), drinking water intake (litter/day), daily live weight gain and feed conversion ratio were also recorded. The current results indicated that rumination, feeding duration, and the visiting feed number were significantly (P ≤ 0.05) higher in T2 than T1 and T3 groups. However, no-differences were noticed among T1, T2 and T3 groups regarding standing time, lying time, standing bouts, dry matter intake, water intake, daily live weight gain, and feed conversion ratio. In conclusion, adding zinc to fresh drinking water improved rumination, feeding duration and the feed visiting number.
... However, several different seaweeds have been fed to cattle and include brown seaweeds (Ascophyllum nodosum), and Saragssum wightii. A commercial product 'Tasco' has been developed based on A. nodosum [3]. ...
There has been considerable interest in the use of red seaweed, and in particular Asparagopsis taxiformis , to increase production of cattle and to reduce greenhouse gas emissions. We hypothesized that feeding seaweed or seaweed derived products would increase beef or dairy cattle performance as indicated by average daily gain (ADG), feed efficiency measures, milk production, and milk constituents, and reduce methane emissions. We used meta-analytical methods to evaluate these hypotheses. A comprehensive search of Google Scholar, Pubmed and ISI Web of Science produced 14 experiments from which 23 comparisons of treatment effects could be evaluated. Red seaweed ( Asparagopsis taxiformis ) and brown seaweed ( Ascophyllum nodosum) were the dominant seaweeds used. There were no effects of treatment on ADG or dry matter intake (DMI). While there was an increase in efficiency for feed to gain by 0.38 kg per kg [standardized mean difference (SMD) = 0.56; P = 0.001] on DerSimonian and Laird (D&L) evaluation, neither outcome was significant using the more rigorous robust regression analysis (P >0.06). The type of seaweed used was not a significant covariable for ADG and DMI, but A . nodosum fed cattle had lesser feed to gains efficiency compared to those fed A . taxiformis . Milk production was increased with treatment on weighted mean difference (WMD; 1.35 ± 0.44 kg/d; P <0.001); however, the SMD of 0.45 was not significant (P = 0.111). Extremely limited data suggest the possibility of increased percentages of milk fat (P = 0.040) and milk protein (P = 0.001) on (D&L) WMD evaluation. The limited data available indicate dietary supplementation with seaweed produced a significant and substantial reduction in methane yield by 5.28 ± 3.5 g/kg DMI (P = 0.003) on D&L WMD evaluation and a D&L SMD of −1.70 (P = 0.001); however, there was marked heterogeneity in the results ( I 2 > 80%). In one comparison, methane yield was reduced by 97%. We conclude that while there was evidence of potential for benefit from seaweed use to improve production and reduce methane yield more in vivo experiments are required to strengthen the evidence of effect and identify sources of heterogeneity in methane response, while practical applications and potential risks are evaluated for seaweed use.
... Other studies reported that feeding lambs and beef cattle exposed to the elevated ambient temperature during walking and transportation or during daytime in animals' yards on Ascophyllum nodosum (brown seaweed) or its extract (Tasco) lowered significantly their ear canal temperatures and RT, respectively (Archer et al., 2007;Williams et al., 2009). Actually, the environmental HS increased the consumption of water and decreased the feed intake, as well as promoted the production of free radicals and affected the endocrine functions, which may disturb the animal metabolism especially the glucose and lipid metabolism (Belhadj Slimen et al., 2016). ...
Heat stress (HS) is the most potent environmental stressors for livestock in tropical and subtropical regions. HS induced splanchnic tissue hypoxia and intestinal oxidative damage, leading to endotoxemia and systemic inflammation. The present study evaluated and compared the modulatory effects of feeding Barki male sheep (Ovis aries) on a standard concentrated diet containing 2% or 4% of the brown seaweed (Sargassum latifolium) followed by roughage for 40 consecutive days on the toxicity-induced by exposure to severe environmental HS (temperature-humidity index = 28.55 ± 1.62). The present study showed that the diet containing Sargassum latifolium (especially 4%) modulated significantly (P < 0.05–0.001) almost all changes shown in the HS-exposed sheep including the increase in the thermo-respiratory responses (skin and rectal temperatures, and respiration rate) and the resulted dyslipidemia, anemia, and systemic inflammation (blood leukocytosis, the elevation in the erythrocyte sedimentation rate, and the increase in serum proinflammatory cytokines and heat shock protein-70 concentrations). In addition, Sargassum latifolium improved significantly (P < 0.05–0.001) the body-weight gain, kidney functions (especially at the high dose), and blood antioxidant defense system (total antioxidant capacity and the activities of catalase and superoxide dismutase) in the HS-exposed sheep, as well as protected the animals from oxidative tissue damage and the risk of atherosclerosis. In conclusion, feeding sheep with the diet containing 4% of Sargassum latifolium was safe and suitable for animal nutrition, as well as efficiently alleviated the harmful effects of the environmental HS in Barki sheep through improving the animal antioxidant defense system, and regulating the thermo-respiratory and inflammatory responses.
... High-energy feeds, however, can increase internal body temperature and may consequently result in heat stress. Consequences of heat stress can lead to economic losses particularly during the hot seasons (Williams et al., 2009). Providing shade and more water points can be strategies for reducing high heat load in cattle. ...
The present study investigated the optimum blending condition of protected fat, choline and yeast culture for lowering of rumen temperature. The Box Benken experimental design, a fractional factorial arrangement, and response surface methodology were employed. The optimum blending condition was determined using the rumen simulated in vitro fermentation. An additive formulated on the optimum condition contained 50% of protected fat, 25% of yeast culture, 5% of choline, 7% of organic zinc, 6.5% of cinnamon, and 6.5% of stevioside. The feed additive was supplemented at a rate of 0.1% of diet (orchard grass:concentrate, 3:7) and compared with a control which had no additive. The treatment resulted in lower volatile fatty acid (VFA) concentration and biogas than the control. To investigate the effect of the optimized additive and feed energy levels on rumen and rectal temperatures, four rumen cannulated Hanwoo (Korean native beef breed) steers were in a 4×4 Latin square design. Energy levels were varied to low and high by altering the ratio of forage to concentrate in diet: low energy (6:4) and high energy (4:6). The additive was added at a rate of 0.1% of the diet. The following parameters were measured; feed intake, rumen and rectal temperatures, ruminal pH and VFA concentration. This study was conducted in an environmentally controlled house with temperature set at 30°C and relative humidity levels of 70%. Steers were housed individually in raised crates to facilitate collection of urine and feces. The adaptation period was for 14 days, 2 days for sampling and 7 days for resting the animals. The additive significantly reduced both rumen (p
... Cattle housed in a climatic chamber and exposed to 23 days of heat stress revealed that complete recovery of feed intake was obtained only after 10 days at thermoneutrality. After reestablishment of thermoneutrality, respiration rates returned to normal level, while rectal temperature undershot, possibly indicating adaptation to heat stress (Williams et al., 2009). In analogous conditions, Beatty (2005) found similar results. ...
The aim of this study was to determine the effects of body condition score to metabolic acclimation in heat stressed Holstein cows. Body condition of cows had no effect on any of the tested parameters during the thermal neutral period, except for the percentage of protein in milk. Heat stress has been demonstrated to have an impact on all the selected parameters, and has been found to be the cause of decreased milk production and quality, increased rectal temperature and respiration rate, decreased glucose, non esterified fatty acids (NEFA) and cholesterol concentration, increased urea and bilirubin concentration, and loss of subcutaneous fat. Obese cows (BCS > 4) had less ability of acclimation to heat stress as compared to normal and thin cows (significantly lower production and milk quality, and significantly higher rectal temperature and respiration level in relation to the other groups of cows). Obese cows showed a significantly higher concentration of NEFA and significantly lower glucose during exposure to heat stress. The steady increase in NEFA concentrations and decrease of backfat thickness suggested that fat was used for energy purposes, which significantly increased the heat balance and led to poor acclimation to heat stress in obese cows. Cows with high body condition were at higher risk of developing liver failure and lipidosis (reduced cholesterol and elevated bilirubin concentration) during heat stress, which could be linked with increased concentrations of fatty acids in the blood. This was found with an increased concentration of urea during exposure to heat stress, with significantly higher concentration in obese cows. Using the fat for energy purposes depends on the sensitivity to insulin, which increases during heat stress. Obese cows are naturally less sensitive to insulin and more prone to lipolysis. However, these signs should be the focus of future research.
... The effect of a ration containing 1% Tasco meal fed for 45 days in reducing body temperature of steers during heat stress was investigated using temperature and humidity controlled environmental chambers (Williams et al. 2009). Eight of 24 steers were fitted with ruminal cannulae to measure in situ disappearance of neutral detergent fiber during the four experimental periods. ...
Aqueous extracts of Ascophyllum nodosum and several other brown seaweeds are manufactured commercially and widely distributed for use on agricultural crops. The increasingly regulated international trade in such products requires that they be standardized and defined to a degree not previously required. We examined commercially available extracts using quantitative 1H NMR and principal components analysis (PCA) techniques. Extracts manufactured over a 4-year period using the same process exhibited characteristic profiles that, on PCA, clustered as a discrete group distinct from the other commercial products examined. In addition to recognizing extracts made from different seaweeds, analysis of the 1H spectra in the 0.35–4.70 ppm region allowed us to distinguish amongst extracts produced from the same algal species by different manufacturers. This result established that the process used to make an extract is an important variable in defining its composition. A comparison of the 1H NMR integrals for the regions 1.0–3.0 ppm and 3.0–4.38 ppm revealed small but significant changes in the A. nodosum spectra that we attribute to seasonal variation in gross composition of the harvested seaweed. Such changes are reflected in the PCA scores plots and contribute to the scatter observed within the data point cluster observed for Acadian soluble extracts when all data are pooled. Quantitative analysis using 1H NMR (qNMR) with a certified external standard (caffeine) showed a linear relationship with extract concentration over at least an order of magnitude (2.5–33 mg/mL; R
2 > 0.97) for both spectral regions integrated. We conclude that qNMR can be used to profile (or “fingerprint”) commercial seaweed extracts and to quantify the amount of extract present relative to a suitably chosen standard.
... The effect of a ration containing 1% Tasco meal fed for 45 days in reducing body temperature of steers during heat stress was investigated using temperature and humidity controlled environmental chambers (Williams et al. 2009). Eight of 24 steers were fitted with ruminal cannulae to measure in situ disappearance of neutral detergent fiber during the four experimental periods. ...
Both micro- and macroalgae have long been used to augment plant productivity and food production in various regions of the
world through their beneficial effects when applied to soils. Interactions of algae with the soil community undoubtedly are
complex and benefits are dependent on the crop and the local environmental conditions. This has resulted in much speculation
as to mechanisms involved as well as the validity of the results reported. It is now 60years since the first commercial seaweed
extract was manufactured for agricultural use. These aqueous extracts allowed for the first time the direct application of
soluble seaweed constituents to specific plant organs such as leaves and roots. The earlier concept that benefits of seaweeds
and their extracts were due mainly to their manurial value or to their micronutrient suites is no longer tenable. Seaweeds
likewise have been used for millennia as fodder supplements to improve animal nutrition and productivity. Recent research
is focusing on their mode of action, specific health benefits, and the mechanisms of action in animals. Improved analytical
techniques and instrumentation coupled with the use of molecular genetic tools are establishing that seaweed extracts can
modify plant and animal responses at a fundamental level. It therefore seems appropriate to review key developments over the
years and to remark on novel findings. A new and exciting vista has opened for seaweed extracts in both plant and animal applications.
KeywordsAlgae–Growth hormones–Pathogen resistance–Animal health–Polymers
Music plays a significant developmental role in the life of adolescents and has different functions in the life of an individual. Listening to music is one of the most important activities of adolescents, while their music preferences reflect their values, conflicts, and developmental problems they are faced with in everyday life. It is important to understand how adolescents use and experience music on a daily basis and what factors impact their use of music. The power of preference for a specific kind of music depends on the degree to which that type of music fulfills certain functions because the level of functionality and the power of music preference are correlated. While identity formation, peer socialization, and social perception remain important functions of music throughout one's life, they are especially important in the period of adolescence. To understand better the strong links between music preferences and the functions of music in an individual's life, it is important to include the personality factor that provides practical and relevant information about what makes us who we are. Music education can influence the music preferences of young people because listening to music is an important activity in their leisure time. The paper presents theoretical models of music preferences, characteristics of music, contexts of listening to music, correlation between music preferences and personality traits, as well as the functions of music that are most relevant in the life of adolescents.
Seaweeds are macroalgae, which can be of many different morphologies, sizes, colors, and chemical profiles. They include brown, red, and green seaweeds. Brown seaweeds have been more investigated and exploited in comparison to other seaweed types for their use in animal feeding studies due to their large size and ease of harvesting. Recent in vitro and in vivo studies suggest that plant secondary compound-containing seaweeds (e.g., halogenated compounds, phlorotannins, etc.) have the potential to mitigate enteric methane (CH4) emissions from ruminants when added to the diets of beef and dairy cattle. Red seaweeds including Asparagopsis spp. are rich in crude protein and halogenated compounds compared to brown and green seaweeds. When halogenated-containing red seaweeds are used as the active ingredient in ruminant diets, bromoform concentration can be used as an indicator of anti-methanogenic properties. Phlorotannin-containing brown seaweed has also the potential to decrease CH4 production. However, numerous studies examined the possible anti-methanogenic effects of marine seaweeds with inconsistent results. This work reviews existing data associated with seaweeds and in vitro and in vivo rumen fermentation, animal performance, and enteric CH4 emissions in ruminants. Increased understanding of the seaweed supplementation related to rumen fermentation and its effect on animal performance and CH4 emissions in ruminants may lead to novel strategies aimed at reducing greenhouse gas emissions while improving animal productivity.
Brown seaweed (BSW; Ascophyllum nodosum) extract supplement has been reported to positively affect antioxidant activity, vitamin E status, immune cell response, and carcass characteristics in farm animals. Preharvest diet containing BSW has also been reported to reduce fecal shedding of E. coli and other enteric bacteria in livestock. This review focuses on the effects of brown seaweed extract supplementation on small ruminants.
A study was conducted to evaluate the effect of Tasco (Ascophyllum nodosum; Acadian Seaplants Limited, Dartmouth, Nova Scotia, Canada) on alleviation of heat stress in dairy cows. Thirty-two cows were randomly assigned (randomized complete block design) to 4 treatments: control-1 (C-1); control for period 2 and 0.50% Tasco for period 3 (C-.5T); 0.25% Tasco (0.25T); 0.50% Tasco (0.5T). The study was divided into 3 periods: period 1 (7 d; adaptation to Calan Gate system); period 2 [28 d; C-1 and C-.5T representing the control (CON)]; period 3 (28 d; C-.5T was changed to 0.50% Tasco to evaluate duration of feeding Tasco and other groups remained unchanged). Respiration rate and rump and ear skin temperatures were measured at 0700, 1600, and 1900 h. Core body temperature was recorded every 20 min with telemetric temperature transmitters in the reticulum. Tasco had no effect (P > 0.10) on milk production, but DMI was occasionally less (P < 0.05) for 0.25T cows than for CON cows in period 2. The rump skin temperature of 0.25T cows was reduced (P < 0.05) for some hours in period 2 and for some days in period 3. Linear regression of core body temperature and rump skin temperature versus ambient temperature in period 3 revealed less (P < 0.05) increase for 0.25T than for the control as ambient temperature increased. These results suggest that inclusion of 0.25% Tasco reduced body temperature response to increasing ambient temperature and sustained milk production, even with reduced DMI. No benefit of 0.50% Tasco was seen when fed for 28 or 56 d. Limited benefits of Tasco were observed in this study.
The Giant freshwater prawn (GFP), Macrobrachium rosenbergii, is one of the most important crustacean species cultured in China, but information on the genetic diversity of GFP in China is still limited. In this study we analyzed the genetic diversity of 6 cultured GFP populations collected in China, and 2 wild populations from Viet Nam. The wild populations were included as a reference so that the genetic diversity of the introduced cultured GFP populations could be evaluated. We used six polymorphic primer pairs to estimate genetic diversity. Results showed that the number of alleles per locus ranged from 6 to 19. The mean observed heterozygosity (0.364 ± 0.090) was less than the expected heterozygosity (0.893 ± 0.016); highly significant deficiencies in heterozygotes were detected (100%). The polymorphism information content (PIC) of 8 populations at 6 loci was greater than 0.5 (varying from 0.616 to 0.912). Pair-wise genetic differentiation (FST) varied from 0.006 to 0.129 among the eight populations. The dendrogram based on genetic distance showed six populations distributed on the same major branch, suggesting that they have closely genetic distance and two populations (ZJC and GDB) distributed on the other branch, so they also have closely genetic distance. The results of study provide a baseline assessment of genetic diversity in some populations in China and Viet Nam that will be useful for the development of breeding programmes in the future.
Early scientific studies conducted at the turn of the twentieth century failed to support the inclusion of seaweeds into animal rations at high inclusion rates. At that time, based on proximate analysis and energy availability studies, dried seaweeds or kelp meal largely fell out of favor as a recommended animal feed source. Nevertheless, kelp meal was still regarded by some as having properties which improved animal health and productivity which were not conveniently explained by conventional feed analysis. In the 1970s, research leads to the discovery that chelated micromineral sources were more efficient for the delivery of microelements than conventional inorganic sources. This prompted renewed interest in seaweeds as rich sources of over 60+ microelements. However, it was only in the early 2000s, when detailed analysis of the complex structure of the polysaccharides associated with seaweeds was tied to their prebiotic actions, that a clear explanation for the basis of productivity and health enhancement was attained. Further analysis indicated that other constituents in various brown seaweeds such as phlorotannins and antioxidants also contributed to the observed bioactivities. Of all of the brown seaweeds cited in studies, the one most scientifically documented is Ascophyllum nodosum, and of all of these sources, Tasco®, a sundried, high-quality macroalgal product, produced by Acadian Seaplants has been the most studied. The latest studies of Tasco® suggest prebiotic potencies at least five times that of the reference prebiotic inulin with additional performance-enhancing benefits in animal rations that rival antibiotic inclusions.
The present experiment was designed to investigate the subsequent influences of supplementing different levels of intact green seaweed Ulva lactuca (0, 3, and 5 % DM) to growing sexually immature lambs during the growth period (74 d) on the seminal and testicular characteristics of sexually mature rams. Ulva lactuca was manually collected, adequately prepared, and then incorporated into lamb's diets. Eighteen male 3-months old lambs of Awassi breed with a mean body weight of 22.57 kg (SD=1.08) were randomly assigned into treatments. The obtained results indicated that offering Ulva lactuca at the level of 3 or 5 % DM to lambs during the growth period had no subsequent impacts (P > 0.05) on liver and kidney functions as well as blood water balance in rams; thereby, suggesting that Ulva lactuca can be safely supplemented to lambs during growing. However, our findings point out that feeding a lamb diet supplemented with intact Ulva lactuca failed to demonstrate any subsequent benefit (P > 0.05) on the growth performance, thermoregulatory responses, and plasma oxidative status in rams. Above all, it was clearly evident that supplementing intact Ulva lactuca to lambs had demonstrated subsequent negative influences (P < 0.05) on seminal and testicular characteristics of rams, and more noticeably observed at 5% DM inclusion rate than 3 %. These were manifested by the inferior (P < 0.05) seminal quality, reduced (P < 0.05) testicular morphometry, changes (P < 0.05) in testicular histopathology, defective (P < 0.05) endocrine signaling, and increased (P < 0.05) seminal oxidative stress in rams fed diets supplemented with Ulva lactuca during the growth period compared to control rams. The deleterious impacts of feeding intact Ulva lactuca on spermatogenesis and germ cell loss were proven to be attributed to the dysfunctionality of Sertoli cells. Collectively, these results provide novel insights on the subsequent influences of dietary supplementation of intact Ulva lactuca to lambs. The consistent evidences of profound negative impacts on seminal and testicular characteristics as well as the resulted data of no improvement of subsequent growth, thermoregulation, and plasma oxidative status in rams prompt us to tentatively recommend the avoidance of feeding intact Ulva lactuca to lambs.
The aim of this study was to determine the effects of body condition score to metabolic acclimation in heat stressed Holstein cows. Body condition of cows had no effect on any of the tested parameters during the thermal neutral period, except for the percentage of protein in milk. Heat stress has been demonstrated to have an impact on all the selected parameters, and has been found to be the cause of decreased milk production and quality, increased rectal temperature and respiration rate, decreased glucose, non esterified fatty acids (NEFA) and cholesterol concentration, increased urea and bilirubin concentration, and loss of subcutaneous fat. Obese cows (BCS>4) had less ability of acclimation to heat stress as compared to normal and thin cows (significantly lower production and milk quality, and significantly higher rectal temperature and respiration level in relation to the other groups of cows). Obese cows showed a significantly higher concentration of NEFA and significantly lower glucose during exposure to heat stress. The steady increase in NEFA concentrations and decrease of backfat thickness suggested that fat was used for energy purposes, which significantly increased the heat balance and led to poor acclimation to heat stress in obese cows. Cows with high body condition were at higher risk of developing liver failure and lipidosis (reduced cholesterol and elevated bilirubin concentration) during heat stress, which could be linked with increased concentrations of fatty acids in the blood. This was found with an increased concentration of urea during exposure to heat stress, with significantly higher concentration in obese cows. Using the fat for energy purposes depends on the sensitivity to insulin, which increases during heat stress. Obese cows are naturally less sensitive to insulin and more prone to lipolysis. However, these signs should be the focus of future research.
In this article, we focus on solving the energy optimization problem for real-time streaming applications on multiprocessor System-on-Chip by combining task-level coarse-grained software pipelining with DVS (Dynamic Voltage Scaling) and DPM (Dynamic Power Management) considering transition overhead, inter-core communication and discrete voltage levels. We propose a two-phase approach to solve the problem. In the first phase, we propose a coarse-grained task parallelization algorithm called RDAG to transform a periodic dependent task graph into a set of independent tasks by exploiting the periodic feature of streaming applications. In the second phase, we propose a scheduling algorithm, GeneS, to optimize energy consumption. GeneS is a genetic algorithm that can search and find the best schedule within the solution space generated by gene evolution. We conduct experiments with a set of benchmarks from E3S and TGFF. The experimental results show that our approach can achieve a 24.4% reduction in energy consumption on average compared with the previous work.
Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.
Effects of applying Tasco-Forage, an Ascophyllum nodosum seaweed-based product prepared by a proprietary process, to endophyte (Neotyphodium coenophialum [Morgan-Jones and Gams] Glenn, Bacon, and Hanlin)-infected and endophyte-free tall fescue (Festuca arundinacea Schreb.) were studied in each of 3 yr (1995, 1996, and 1997) in Virginia and in 1996 and 1997 in Mississippi. There were 48 steers at each location in each year (n = 240) in a 2 x 2 x 2 factorial arrangement with two replications at each location. Steers in Virginia were Angus and Angus x Hereford with initial weights of 245 kg (SD = 20), 234 kg (SD = 9), and 265 kg (SD = 5) in yr 1, 2, and 3, respectively. Steers in Mississippi were 3/4 Angus and 1/4 Brahman and weighed 230 kg (SD = 8) and 250 kg (SD = 2) in yr 2 and 3, respectively. Tasco (3.4 kg/ha) was dissolved in water and applied to pastures in April before grazing was begun and again in July at the same rate. The grazing period was from mid-April to late September or mid-October. Total gains were higher (P < 0.05) for steers grazing uninfected than for those grazing endophyte-infected tall fescue. Rectal temperatures were increased (P < 0.05) due to endophyte infection at both locations; Tasco application decreased temperature of steers grazing infected fescue in Virginia (interaction, P < 0.07) but increased temperatures of steers grazing infected fescue in Mississippi (interaction, P < 0.05). Presence of the endophyte resulted in rough hair coats and loss of hair color, but the effect was partially offset (P < 0.05) by Tasco application in Virginia in 1995. Both monocyte phagocytic activity (all years and locations) and major histocompatibility complex class II expression (1995 only) were decreased (P < 0.05) in steers due to endophyte infection, but this effect was reversed (P < 0.05) by application of Tasco to pastures. Application of the extract from A. nodosum seems to have use in alleviating adverse effects of endophyte on immune function and may improve hair coat condition in cattle grazing infected fescue, but effects on rectal temperature varied due to location.
Five ruminally, duodenally, and ileally cannulated steers (376 +/- 8.1 kg of initial BW) were used in a 5 x 5 Latin square to evaluate effects of cooked molasses block supplementation and inclusion of fermentation extract (Aspergillus oryzae) or brown seaweed meal (Ascophyllum nodosum) on intake, site of digestion, and microbial efficiency. Diets consisted of switchgrass hay (6.0% CP; DM basis) offered ad libitum, free access to water, and one of three molasses blocks (0.341 kg of DM/d; one-half at 0600 and one-half at 1800). Treatments were no block (control), block with no additive (40.5% CP; POS), block plus fermentation extract bolused directly into the rumen via gelatin capsules (2.0 g/d; FS), fermentation extract included in the block (2.0 g/d; FB), and seaweed meal included in the block (10 g/d; SB). Steers were adapted to diets for 14 d followed by a 7-d collection period. Overall treatment effect on hay OM intake tended (8.1 vs. 7.6 +/- 0.5 kg/d; P = 0.14) to increase with block supplementation. Total OM intake (8.4 vs. 7.6 +/- 0.5 kg/d; P = 0.01) increased in steers consuming block compared with control. Apparent and true ruminal OM digestibility increased (P = 0.05) with block consumption. Steers fed SB had greater (P = 0.10) true ruminal OM digestibility compared with steers fed POS (61.0 vs. 57.9 +/- 1.6%). True ruminal CP digestibility increased (P = 0.01) with block supplementation compared with control (37.5 vs. 23.6 +/- 3.7%). Addition of fermentation extract did not affect intake or digestion. Treatments did not alter ruminal pH, total VFA, or individual VFA proportions; however, ruminal ammonia increased (P = 0.01) with block supplementation. In situ disappearance rates of hay DM (3.14 +/- 0.44 %/h), NDF (3.18 +/- 0.47 %/h), and ADF (3.02 +/- 0.57 %/h) were not altered by treatment. Seaweed block increased (P = 0.01) slowly degraded CP fraction compared with POS (39.5 vs. 34.0 +/- 2.07%). Similarly, SB increased (P = 0.01) the extent of CP degradability (74.2 vs. 68.9 +/- 1.81%). No treatment effects (P = 0.24) were observed for microbial efficiency. Block supplementation increased intake, and use of brown seaweed meal seemed to have beneficial effects on forage digestibility in low-quality forage diets.
Summary Specific variables associated with the in situ digestion of soybean meal (SBM) were identified and investigated. Soybean meal was incubated in situ for seven periods of time ranging from 1 to 48 h. Bags were introduced into the tureen in two ways: (1) all bags introduced at the same time and (2) bags introduced at different times (all removed at once). The latter procedure resulted in higher rate constants for both dry matter (DM) and nitrogen (N) disappearance. Dry matter disappearance rates of cottonseed meal were not different between four cows in similar stages of lactation. However, differences developed within cows over a 6-wk period. Correction for bacterial N did not significantly alter rate of SBM N disappearance compared with no correction. The amount of SBM DM and N washed from bags before ruminal ex- posure varied with sample grind and weight. Disappearance was higher for bags with poros- ities of 80 and 102/am compared with 6, 20, 40 or 59 /am. Grinding SBM at 1, 2, 5 mm or unground did not influence rate constants for DM or N disappearance from polyester bags. As the ratio of sample weight to surface area increased (2.5, 12.6, 25.3 and 37.9 mg/cm2), DM and N disappearance rates decreased. Bag porosities of 6 and 20 ~m gave lowest and 80 and 102 /am highest rate constants of in situ DM and N disappearance. For SBM, a sample weight to surface area ratio of 12.6 mg/cm 2 and use of bags with porosities of 40, 59, 80 and 102/am resulted in acceptable estimates of ruminal protein availability.
Estimates of the degradability of protein in the rumen are essential for the application of new systems which have been suggested for the evaluation of the protein requirements of ruminants (Agricultural Research Council, 1980). The effective percentage degradability (P) of protein supplements in the rumen is dependent not only on the course of degradation of the protein particles in the rumen, but also on the time distribution of their stay in the rumen, and will decrease if there is an increase in the rate of passage of the particles. It was shown by Ørskov & McDonald (1979) that if the percentage protein disappearance (p) from samples incubated for time t is described by the equation
Much of the fescue throughout the world contains an endophytic fungus which protects the plant from heat and drought, but produces a condition known as fescue toxicosis when consumed by animals. Major symptoms include reduced feed intake and growth, and increased hyperthermia during heat stress. Seaweed extract was tested, using both rodent and bovine models, to determine potential for reduction of fescue toxicosis-induced hyperthermia. Results show that the seaweed extract reduces hyperthermia associated with fescue toxicosis.
Researchers have traditionally predicted animal responses by means of statistical models. This study was conducted to evaluate modelling techniques. One hundred and twenty-eight feedlot heifers were observed during a 2-month period during the summer of 2002. Respiration rate and surface temperature were taken on a random sample of 40 animals twice a day. Five different models (two statistical models, two fuzzy inference systems, and one neural network) were developed using 70% of this data, and then tested using the remaining 30%. Results showed that the neural network described the most variation in test data (68%), followed by the data-dependent fuzzy model (Sugeno type) (66%), regression models (59 and 62%), while the data-free fuzzy model (Mamdami type) described only 27%. While the neural-network model may be a slightly better approach, the researcher may learn more about responses using a fuzzy inference system approach. For all models tested, respiration rate is over-predicted at low stress conditions and under-predicted at high stress conditions. This suggests that all models are lacking a key piece of input data, possibly the accumulative effects of prior weather conditions, to make an accurate prediction.
Thermoregulatory responses, based on non-invasive tympanic temperature measures, are a logical energetically-based alternative to endocrine or other measures for objectively characterizing stress. Tympanic temperature datasets obtained from growing, ad-libitum-fed cattle (Bas taurus steers) were used to compute the fractal dimension for thermoregulatory responses to a non-stressing and several heat-stressing conditions. Within defined limitations for sampling interval frequency, results showed clear differentiation among responses to the imposed environments by individual animals. Objective characterization of stress was attained and a threshold limit for stress defined using the technique.
There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. The original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306; Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Triethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and beta-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch, their fermentations are like that of cellulose but faster and yield no lactic acid. Physical and biological properties of carbohydrate fractions are more important than their intrinsic composition.
The focal point of this limited review is bioenergetic research conducted in the Biological Engineering Research Unit at the U.S. Meat Animal Research Center (MARC), using recently developed instrumentation and analytical techniques. The dynamics of observed thermoregulatory responses in cattle to thermal heat load challenges are explored, with an emphasis on physiological and behavioral parameters of body temperature, respiration rate, and feed intake. Observations of body temperature, especially tympanic temperature, have shown hot environments to cause phase shifts, increased amplitude, and increased means for diurnal rhythms. Fractal analysis of body temperature records obtained at 2- to 10-min intervals has been found to be robust for objectively differentiating among responses of cattle in cool to hot environments, and it indicates a stress threshold of approximately 25 degrees C (coincident with declining feed intake). Other analyses determined a 21 degrees C threshold for increased respiration rate. The reported observations and analyses provide further understanding of how and why the animals respond to environmental challenges, an understanding that is necessary for refining performance models and developing energetic and thermoregulatory models. The dynamic responses are discussed in the context of establishing criteria for proactive environmental management for cattle during hot weather, using heat waves as an example.
The responses of lactating Holstein cows to daily administration of bovine somatotropin (bST) were measured at thermoneutrality (Tn) and under both constant and cycled heat-stress conditions to determine the relationship between thermal status and bST-induced shifts in milk production. All tests included a 5-d acclimation period at Tn (18 degrees C), followed by a 2-d increase in ambient temperature to 28.5 degrees C. After d 3, ambient temperature was cycled between 28.5 (day) and 25.5 degrees C (night) for 4 d. Daily injections with either 31 mg of bST or saline began on d 1 of the experiment. Milk production, feed intake, and respiratory rate (RR) were measured daily. Intraperitoneal, telemetric temperature transmitters were used for a continuous measure of core body temperature (T(core)). Blood samples were collected during each phase to evaluate the changes in serum chemistry in response to bST and heat stress. Following a 15-d recovery, cows were switched across injection treatments and the study was repeated. Milk production decreased by approximately 18.4% below the initial yield at Tn by the end of 7 d of heat challenge. Although a reduction in milk production occurred during heat stress in both groups, milk production was higher in bST-treated cows compared with control cows during periods of constant and cyclic heat. Likewise, bST treatment during the entire period increased the milk-to-feed ratio over the control level by approximately 11.3%. Plasma insulin-like growth factor 1 and serum nonesterified fatty acids accompanied the increased growth hormone level with bST treatment (approximately 122.0 and 88.8%, respectively), whereas plasma urea nitrogen was reduced by approximately 13.3% to reflect the shift to lipid metabolism. There was no difference in T(core) of the treatment and control groups at Tn. Both bST and control cows increased RR and T(core) above the Tn level by approximately 94.8 and 2.9%, respectively, during constant heat, with a greater increase in T(core) of bST-treated compared with control cows (approximately 0.6%). The increase in RR during heat stress preceded T(core) by 1 d for both groups. During cyclic heat, T(core) decreased by approximately 0.4% compared with constant heat in both the control and bST-treated groups. Bovine somatotropin treatment increased milk production similarly during the Tn and heat-stress periods, approximately 8.3% over the control; however, the bST-induced increase in milk-to-feed ratio was greatest during the continuous and cyclic heat-stress phases, approximately 16.2%. This increase occurred together with the elevation in T(core).