L E Armentano

University of Wisconsin–Madison, Madison, Wisconsin, United States

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Publications (78)158.74 Total impact

  • C M Stoffel, P M Crump, L E Armentano
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    ABSTRACT: Dietary fatty acids can affect both milk fat yield and fatty acid (FA) composition. This relationship is well established when the dietary level of FA exceeds 3% of diet dry matter (DM). We could find no reports directly examining the effects of dietary FA profile on milk fat at levels below 3%. Twenty-four primiparous and 36 multiparous lactating cows were paired by production (1 high with 1 low, within parity) to form 30 experimental units. Pairs were fed 6 diets in five 6 × 6 balanced Latin squares with 21-d periods, and data were collected during the last 5 d of each period. Two control diets were fed: a corn control diet (CC; 29% corn silage, 16% alfalfa silage, 19% corn grain, and 8% distillers grain on a DM basis) containing 1.8% FA; and a low-oil control diet (LOC; 9% corn silage, 35% alfalfa silage, 20% food-grade corn starch, and 8% corn gluten feed on a DM basis) containing 1.2% FA. A portion of the food-grade corn starch in LOC was replaced with 4 different FA supplements to create the 4 treatment diets. Treatments were 1.7% (DM basis) of a 50:50 blend of corn oil and high-linoleic safflower oil (LO), 1.7% high-oleic sunflower oil (OO), 1.7% palm oil (PO), or 1.8% calcium salts of palm fatty acids (PFA). The resultant diets were thus enriched in linoleic (LO), oleic (OO), or palmitic acid (PO and PFA). Dietary treatments did not affect dry matter intake. Addition of any of the fat sources to LOC resulted in increased milk yield, but milk fat yields and milk FA composition were variable for the different treatments. The LO treatment resulted in lower milk fat yield, fat concentration, and C16:0 yield but increased both trans-10 C18:1 and trans-10,cis-12 C18:2 yields compared with the other added FA treatments. Diets PO and PFA resulted in increased milk C16:0 yield and decreased total milk C18 yield compared with OO. Regression analysis revealed a negative coefficient for dietary linoleic acid content over basal (LOC) for both milk short-chain FA yield and C16:0 yield. Dietary linoleic acid content also had a positive coefficient for milk trans-10 C18:1 and trans-10,cis-12 conjugated linoleic acid yield. These results demonstrate that even when total dietary FA are below 3%, free oils rich in linoleic acid can reduce milk fat yield by reducing secretion of milk FA with fewer than 18 carbons. Fatty acid composition of fat supplements is important even at this low level of total dietary fat. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
    Journal of dairy science. 10/2014;
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    ABSTRACT: Abstract Text: Improving feed efficiency in dairy cattle is a costly and complex challenge, due to the difficulty in measuring individual animal feed intakes and the need to consider energy demands for growth, lactation, maintenance, health, and fertility. Research projects are underway in several countries to provide genomic breeding values for dry matter intake or residual feed intake of dairy bulls based on genotypes and phenotypes of reference animals in experimental herds. Heritability estimates suggest that direct selection for biological efficiency of feed utilization could lead to significant progress, and this is important because future gains in efficiency due to indirect selection for improved milk yield will be modest. Estimated genetic correlations suggest that residual feed intake is largely independent of the production and type traits currently considered in dairy cattle selection programs, but relationships with health and fertility traits must also be considered. Keywords: dairy cattle genomics feed efficiency
    10th World Congress on Genetics Applied to Livestock Production; 08/2014
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    ABSTRACT: Abstract Text: ABSTRACT: The genetic architecture of residual feed intake (RFI) and related traits was evaluated using a dataset of 2,894 cows. A Bayesian analysis estimated that markers accounted for 14% of the variance in RFI, and RFI had considerable genetic variation. Effects of marker windows were small, but QTL peaks were identified. Six of 8 chromosomes harboring QTL influencing RFI did not contain QTL influencing dry matter intake (DMI), net energy for lactation, or metabolic body weight. In contrast, 7 of 9 chromosomes with QTL influencing DMI also harbored QTL for one or more of the other traits evaluated. These results represent the first genomic analysis of RFI using a large (~3,000 animals) international dataset. In general they suggest RFI is a trait that should respond to selection, and that its genetic regulation is different from that of DMI. Keywords: dairy cattle feed efficiency genome wide association study
    10th World Congress on Genetics Applied to Livestock Production; 08/2014
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    ABSTRACT: Abstract Text: The goal of this study was to identify the effect of weight variation in cow pairs on animal performance and ingestive behavior under competitive conditions. Twenty-four primiparous and 36 multiparous lactating cows were paired (within parity) to form 30 experimental units (feeding gates). Pairs were fed 6 diets in five 6 × 6 balanced Latin squares with 21-d periods, using data from the last 5 d. Each pair had access to one gate that allowed one animal to eat at a time, and cows that filched feeds in other gate were excluded during the statistical analysis. Each dyad was categorized based on the difference in weight within dyad. Differences above average (60 kg) were categorized as High. Below average differences in size were categorized as Low. Within cow pair, individual animals were classified by size as either the larger animal in the pair (Large) or the smaller animal in the pair (Small). The effect of size (large/small) and difference (high/low) were tested. For High and Low difference pairs the number of displacement (gate exchange < 1 min) per week were 55.79 and 90.38 per week, respectively (P<0.05). An interaction between size and difference was significant for dry matter intake, feeding rate, displacements and milk yield, (P< 0.05). In High differences, small cows had greater DMI (% BW) compared to large cows (P<0.05). In Low difference pairs, size did not impact DMI. Milk yield was 4.4 ± 1.1 kg/d lower for Small cows compared to Large cows (P<0.05). For High difference pairs, Size was not associated with milk yield (P>0.05). These results suggest that in highly competitive situations, cows close in size have more aggression, poorer welfare, and milk production than animals with a greater difference in weight. This has implications for identifying animals with poor welfare in competitive environments. Keywords: animal behavior, competition, performance
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
  • Clayton M Stoffel, Louis E. Armentano
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    ABSTRACT: Abstract Text: Dietary fatty acid (FA) composition can affect milk fat yield but also relative yields of different FA. This study examined the effects on yield of individual milk FA resulting from different dietary FA profiles at FA levels below 3% of diet dry matter (DM). Trial design and production performance data were discussed in a 2013 ADSA abstract. Briefly, 60 cows were paired (within parity) to form 30 experimental units. Pairs were fed six diets in five 6x6 balanced Latin squares with 21-d periods. There were two control diets: a corn control diet (CC) containing 1.8% FA and a low oil control (LOC) containing 1.2% FA. A portion of the food grade corn starch in LOC was replaced with 1.7% diet DM of a 50/50 blend of corn and high linoleic safflower oils (CO), high oleic sunflower oil (OO), palm oil (PO), or 1.8% diet DM calcium salts of palm FA (ML, Megalac®) to create four treatment diets that were enriched in either linoleic (CO), oleic (OO), or palmitic acid (PO and ML). Milk FA composition was measured on d 20, and milk yield and fat concentration were measured for the last 5 d of each period; these data were combined to determine yield of individual milk FA. There were significant treatment effects on the yield of 31 out 53 milk FA measured including 10 out of 14 C18:1 isomers (P<0.05). Palmitic acid (C16) yield was lower for CO compared to other treatments (P<0.01) and C18:1 and total C18 yield were higher for OO when compared to PO and ML (P<0.01, P<0.01). Trans-10 C18:1 yield was higher for CO when compared to the other treatments (P<0.01) and for OO compared to PO and ML (P=0.01). Trans-10, cis-12 yield was also higher for CO when compared to all other treatments (P<0.01). Linear regression analysis was also conducted to examine the effect on milk FA yield of the increased dietary linoleic, oleic, and palmitic acid concentrations of the treatment diets over LOC. Dietary linoleic decreased short chain (<C16) and C16 FA yield (P=0.02, P<0.01), dietary oleic increased total C18 yield (P<0.01), and dietary palmitic increased C16 yield (P<0.01). These differences in milk FA profile are consistent with the idea that linoleic acid depresses short chain and C16 FA, resulting in milk fat depression even at dietary FA levels below 3%. Keywords: Biohydrogenation Milk Fat Depression Milk Fatty Acid
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: Continued improvements in feed efficiency are essential for a thriving and sustainable dairy industry. Gross efficiency (GrEff) is defined as the energy captured in milk and body tissues as a percentage of gross energy intake. Our objective was to characterize the relationships among component traits for feed efficiency in lactating Holsteins and to determine their relationships to GrEff. Milk energy output per day (MilkE), calculated from milk, fat, protein, and lactose yields, dry matter intakes (DMI), body weights (BW), and body condition scores (BCS) were collected on 4452 lactating Holstein cows ranging from 50 to 200 days in milk from Scotland, the Netherlands, and the United States. The first 42-day records were analyzed with multivariate animal model in ASREML 3.0. Daily body energy change (dBE) was estimated from body weight change and BCS. Metabolic BW (MBW) was BW to the 0.75 power. GrEff was calculated as (MilkE + dBE) / Gross Energy intake, assuming all diets were 4.5 Mcal/kg. For these cows, MilkE was 26 ± 6 Mcal/d, BW was 600 ± 70 kg, DMI was 22 ± 5 kg/d, and intake as a multiple of maintenance was 3.9 ± 0.6. Genetic correlations for feed efficiency traits were 0.07 ± 0.04 for MilkE and MBW, 0.73 ± 0.03 for MilkE and DMI, and 0.40 ± 0.03 for MBW and DMI. Phenotypic correlations for feed efficiency traits were 0.16 ± 0.02 for MilkE and MBW, 0.60 ± 0.01 for MilkE and DMI, and 0.37 ± 0.01 for MBW and DMI. All correlations were reasonably consistent across countries. Genetic correlations of GrEff with MilkE, MBW, and DMI were 0.61 ± 0.04, -0.14 ± 0.05, and 0.04 ± 0.06, respectively. Phenotypic correlations of GrEff with MilkE, MBW, and DMI were 0.47 ± 0.01, -0.05 ± 0.02, and -0.17 ± 0.01, respectively. We conclude that, for Holsteins at a multiple of maintenance around 4, selection for milk component yield remains the overwhelming determinant of feed efficiency, and that selection for smaller body size may benefit feed efficiency but its impact will be slight compared to selection for more milk. Moreover, selection for greater milk will have a greater impact on profitability than would selection for BW. We suggest that that direct selection for body size (either larger or smaller) is likely not warranted as a means to enhance milk production or feed efficiency. Keywords: lactating dairy cow, feed efficiency, body weight
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: The objective was to validate an in vitro model to predict the total tract fiber digestibility (TTNDFD) in dairy cattle. Nineteen diets from six different trials conducted at University of Wisconsin-Madison were analyzed for fiber digestibility using the in vitro standardized model (Goeser and Combs, 2009). Forages varied amongst diets (corn, alfalfa, tall-fescue and meadow fescue and wheat straw silages) and nutrient composition (NDF ranges from 22.5 to 32.1 %, CP 15.8 to 18.9 % and NFC 38.0 to 51.0 %). Total NDF digestibility observed from the in vivo trials was calculated using indigestible NDF or lignin as marker analyzed in fecal, diet and orts samples. The in vitro TTNDFD model predicts total tract fiber digestibility from the rate of pdNDF degradation (kd, ranges from 1.5 to 4.8 %/h), the rate of passage of pdNDF (kp, ranges from 2.5 to 2.8 %/h) and the proportion of total NDF that is potentially digestible. The kd is calculated from in vitro NDFD measurements taken at 24, 30 and 48 h of incubation using first order kinetics model with an indigestible fraction (Mertens, 1993). Passage of potentially digestible fiber is predicted from a regression model (Krizsan et al., 2010) for iNDF which is adjusted to account for the selective retention of pdNDF (Lund et al., 2006). The pool of indigestible fiber was estimated from 240 h in vitro NDF residues. Data were analyzed using SAS procedure of logistic regression. The coefficient of determination (R2) was used to measure the proportion of variation explained by the model. The range of in vivo TTNDFD was 26.3 to 55.6 % compared to 33.8 to 52.8% for predicted in vitro TTNDFD. The relationship between predicted in vitro TTNDFD and in vivo TTNDFD was TTNDFD in vivo = -5.7531 + 1.1561 TTNDFD in vitro predicted with R² of 61.6%, Root-MSE of 4.3% and p-value of <0.001. The in vitro test of diets from six different trials demonstrated that TTNDFD model can provide important insights into fiber utilization by dairy cattle that could be used in the field. The TTNDFD value can also be used as a stand-alone value to index forages, as already shown in other publications from our lab. The ability to predict total tract fiber digestibility from a model based on in vitroNDF degradation and incorporate this information into rations could improve our ability to optimize forage utilization and milk production. Keywords: iNDF-Fiber-Digestibility
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
  • C Arndt, L E Armentano, M B Hall
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    ABSTRACT: The objective of this study was to determine the effect of substituting corn bran (CB) for dried ground corn grain (CG) in the nonforage portion of high-forage (HF) and low-forage (LF) diets. Twelve multiparous and 12 primiparous Holsteins were assigned to 4 diets using six 4 × 4 Latin squares with 3-wk periods. Forage was 64 or 38% of the total mixed ration (% of dry matter). On a dry matter basis, the HFCG diet had 20% CG, the LFCG diet had 39% CG, the HFCB diet had 19% CB, and the LFCB diet had 38% CB. Digestible organic matter intake (OMI) and milk energy yield were lower for CB compared with CG within forage level. Digestible OMI was greater (1.9 kg/d) for the LFCG compared with the HFCG treatment. When CB replaced forage (LFCB vs. HFCB), digestible OMI was not different but milk energy yield was greater with the LFCB diet. The LFCG diet supported the greatest milk, milk protein, and milk energy yield. Decreased concentration of milk protein and increased concentration of milk urea nitrogen when feeding CB compared with CG suggests that lack of fermentable energy in the CB diets may have limited rumen microbial protein synthesis. Total substitution of CG with CB in the nonforage portion did not support maximum milk production, even when forage was reduced at the same time (HFCG vs. LFCB). Predicted neutral detergent fiber (NDF) digestibility at 1 times maintenance, based on chemical analysis of the individual feeds, was 22 percentage units greater for CB than for the forage mix (68.9 vs. 46.9%). In vitro NDF digestibility (30 h) was 19.4 percentage units greater for CB than for the forage mix (68.9 vs. 49.5%). However, in vivo NDF digestibility of the diet when CB replaced forage (HFCB vs. LFCB) was similar (44.1 vs. 44.5%). Similarly, predicted total digestible nutrients at the production level of intake, based on chemical analysis, were greater for the CB treatments and lower for the CG treatments than those observed in vivo.
    Journal of dairy science. 07/2014;
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    ABSTRACT: Feed efficiency is an economically important trait in the beef and dairy cattle industries. Residual feed intake (RFI) is a measure of partial efficiency that is independent of production level per unit of body weight. The objective of this study was to identify significant associations between single nucleotide polymorphism (SNP) markers and RFI in dairy cattle using the Random Forests (RF) algorithm. Genomic data included 42,275 SNP genotypes for 395 Holstein cows, whereas phenotypic measurements were daily RFI from 50 to 150 d postpartum. Residual feed intake was defined as the difference between an animal's feed intake and the average intake of its cohort, after adjustment for year and season of calving, year and season of measurement, age at calving nested within parity, days in milk, milk yield, body weight, and body weight change. Random Forests is a widely used machine-learning algorithm that has been applied to classification and regression problems. By analyzing the tree structures produced within RF, the 25 most frequent pairwise SNP interactions were reported as possible epistatic interactions. The importance scores that are generated by RF take into account both main effects of variables and interactions between variables, and the most negative value of all importance scores can be used as the cutoff level for declaring SNP effects as significant. Ranking by importance scores, 188 SNP surpassed the threshold, among which 38 SNP were mapped to RFI quantitative trait loci (QTL) regions reported in a previous study in beef cattle, and 2 SNP were also detected by a genome-wide association study in beef cattle. The ratio of number of SNP located in RFI QTL to the total number of SNP in the top 188 SNP chosen by RF was significantly higher than in all 42,275 whole-genome markers. Pathway analysis indicated that many of the top 188 SNP are in genomic regions that contain annotated genes with biological functions that may influence RFI. Frequently occurring ancestor-descendant SNP pairs can be explored as possible epistatic effects for further study. The importance scores generated by RF can be used effectively to identify large additive or epistatic SNP and informative QTL. The consistency in results of our study and previous studies in beef cattle indicates that the genetic architecture of RFI in dairy cattle might be similar to that of beef cattle.
    Journal of Dairy Science 08/2013; · 2.57 Impact Factor
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    C. Leonardi, S. Bertics, L.E. Armentano
    Journal of Dairy Science. 11/2012; 95(11):6830.
  • E A French, S J Bertics, L E Armentano
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    ABSTRACT: The objective of this study was to determine if ruminally infusing volatile fatty acid (VFA) increased concentration of their homologous odd- and branched-chain fatty acid (OBCFA) in rumen contents and milk. The influence of VFA on dry matter intake (DMI), blood metabolites, and blood insulin was also evaluated. Four mid-lactation cows were assigned to a 4×4 Latin square design with 48-h periods. Infusion treatments were acetate (AC), propionate (PR), isovalerate (IV), and anteisovalerate (AIV). Infusions began (time = 0) 5.5 h before feeding at 17.4 mmol of VFA/min and were terminated at 18 h. Infusions rates were well above physiological levels for IV and AIV. Surprisingly, the greatest differences in rumen OBCFA were increases in rumen liquid iso C15:0 and nonbranched C17:0 for AIV. In addition, infusing AIV increased anteiso C15:0 and anteiso C17:0 in rumen solid contents. Infusing IV increased iso C15:0 in both rumen solids and milk. Propionate increased milk C15:0 and C17:0. Both gluconeogenic compounds, PR and AIV, had similar proportions of milk C15:0, which was greater than that obtained with AC and IV. Rumen and blood VFA were as expected, with increased concentrations of the VFA present in the infusate. At 23 h, and consistently throughout infusions, DMI was similar for AC compared with PR and for AIV compared with IV. Both IV and AIV decreased DMI and energy balance; however, only IV increased plasma nonesterified fatty acids (121, 78, 172, and 102 mM for AC, AIV, IV, and PR), increased β-hydroxybutyrate (10.8, 5.9, 51.9, 5.4 mg/dL for AC, AIV, IV, and PR), and reduced plasma glucose (56.3, 59.1, 31.9, and 64.3 mg/dL for AC, AIV, IV, and PR). Rumen and milk OBCFA responses were minimal following infusion of large amounts of IV and AIV, suggesting limited use of IV, and AIV for de novo OBCFA synthesis, either pre- or postabsorption. Minor increases in milk odd-chain fatty acids following large doses of ruminal PR support the presence of postabsorptive synthesis of these milk odd-chain fatty acids.
    Journal of Dairy Science 04/2012; 95(4):2015-26. · 2.57 Impact Factor
  • M He, K L Perfield, H B Green, L E Armentano
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    ABSTRACT: The effect of feeding increasing levels of oleic and linoleic acid both independently and together, with or without monensin, on milk fat depression was evaluated. Fifty-six Holstein cows were blocked by parity and then were divided by milk production into 2 groups (high or low) of 14 cows each within each parity block. A cow pair of 1 high and 1 low production cow within each parity block was fed in a single electronic feeding gate. Gates (n = 28) were considered the experimental unit and were assigned to monensin (17.5 g/t of dry matter) or control as the main plot (n = 14 each). The 7 cow pairs in each of the fixed effect groups were further assigned to a sequence of fat blend diets as split plot. Seven fat blend treatments in the split plot 7 × 7 Latin square were no added fat (no fat) and diets with increasing levels of oleic or linoleic acid: low C18:1 + low C18:2 (LOLL); low C18:1 + medium C18:2 (LOML); low C18:1 + high C18:2 (LOHL); medium C18:1 + low C18:2 (MOLL); medium C18:1+medium C18:2 (MOML); and high C18:1+low C18:2 (HOLL). Monensin feeding did not affect milk yield or concentration and yield of milk fat. Feeding monensin decreased the proportion of C <16, increased the proportion of total C18, increased the proportion and yield of trans-10 C18:1, and increased the proportion of trans-10,cis-12 conjugated linoleic acid in milk fatty acids (FA). As dietary C18:1 or C18:2 increased beyond the concentration present in LOLL, milk fat concentration, milk fat yield, and proportion and yield of milk C <16 all decreased, and the proportion and yield of milk trans-10 C18:1 increased. A quadratic effect on milk fat concentration and yield was noticed for C18:2 feeding, but not for C18:1 feeding. When dietary contents of total FA and FA other than C18:1 and C18:2 were similar, C18:2-rich diets decreased milk fat concentration and yield compared with C18:1-rich diets (LOML vs. MOLL, and LOHL vs. HOLL), indicating that C18:2 is more potent than C18:1 for depressing milk fat. Increasing dietary FA content from no fat to LOLL, which increased primarily C18:1 and C18:2 with small increases in C18:0 and C16:0, decreased the secretion of C <16 but increased total C18 secretion in milk. This suggests that biohydrogenation intermediates act to decrease mammary FA synthesis at low levels of added C18:1 and C18:2. No significant monensin × fat interactions were detected for the milk composition parameters analyzed; however, a monensin × fat interaction was found for milk fat trans-10 C18:1 proportion.
    Journal of Dairy Science 03/2012; 95(3):1447-61. · 2.57 Impact Factor
  • M He, L E Armentano
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    ABSTRACT: This study was conducted to evaluate the effect of dietary supplementation of unprotected vegetable oils differing in fatty acid profiles with or without a commercial antioxidant (Agrado Plus, Novus International, St. Charles, MO) on dairy cattle performance, milk fatty acid profiles, and milk fat depression. Twenty-four multiparous Holstein cows were blocked by production (high and low) and assigned to Agrado Plus or no Agrado Plus diets as the main plot in this experiment. The 6 cows in each of the fixed effect groups (high with and without Agrado, low with and without Agrado) were then assigned to a 6 × 6 Latin square as a split plot with 21-d periods. The 6 dietary treatments in the split-plot Latin square were no added oil (control), or 5% DM as oil from palm (PO), high-oleic safflower (OSAF), high-linoleic safflower (LSAF), linseed (LNSD), or corn (CO). Added oil replaced corn starch in the total mixed ration. Diets were formulated to have similar crude protein and neutral detergent fiber, and consisted of 41.2% alfalfa silage, 18.3% corn silage, and 40.5% concentrate mix (dry matter basis). Feeding Agrado Plus did not affect milk, milk fat, or milk protein production or milk fatty acid composition in this study. No significant differences were found between oil feeding versus control for dry matter intake, milk yield, and milk protein yield, but oils other than PO significantly decreased milk fat concentration and proportion and yield of milk short- and medium-chain fatty acids (C(<16)). Feeding PO effectively maintained milk fat yield (1.18 kg/d) and concentration (3.44%), whereas the oils rich in linoleic acid (CO and LSAF) significantly decreased milk fat yield (0.98 and 0.86 vs. 1.14 kg/d) and concentration (3.05 and 2.83 vs. 3.41%) compared with control. Similar lactation performance between OSAF and LNSD suggests that oleic and linolenic acids are roughly equal in potency of milk fat depression.
    Journal of Dairy Science 05/2011; 94(5):2481-91. · 2.57 Impact Factor
  • T F Gressley, M B Hall, L E Armentano
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    ABSTRACT: Microbial fermentation of carbohydrates in the hindgut of dairy cattle is responsible for 5 to 10% of total-tract carbohydrate digestion. When dietary, animal, or environmental factors contribute to abnormal, excessive flow of fermentable carbohydrates from the small intestine, hindgut acidosis can occur. Hindgut acidosis is characterized by increased rates of production of short-chain fatty acids including lactic acid, decreased digesta pH, and damage to gut epithelium as evidenced by the appearance of mucin casts in feces. Hindgut acidosis is more likely to occur in high-producing animals fed diets with relatively greater proportions of grains and lesser proportions of forage. In these animals, ruminal acidosis and poor selective retention of fermentable carbohydrates by the rumen will increase carbohydrate flow to the hindgut. In more severe situations, hindgut acidosis is characterized by an inflammatory response; the resulting breach of the barrier between animal and digesta may contribute to laminitis and other disorders. In a research setting, effects of increased hindgut fermentation have been evaluated using pulse-dose or continuous abomasal infusions of varying amounts of fermentable carbohydrates. Continuous small-dose abomasal infusions of 1 kg/d of pectin or fructans into lactating cows resulted in decreased diet digestibility and decreased milk fat percentage without affecting fecal pH or VFA concentrations. The decreased diet digestibility likely resulted from increased bulk in the digestive tract or from increased digesta passage rate, reducing exposure of the digesta to intestinal enzymes and epithelial absorptive surfaces. The same mechanism is proposed to explain the decreased milk fat percentage because only milk concentrations of long-chain fatty acids were decreased. Pulse-dose abomasal fructan infusions (1 g/kg of BW) into steers resulted in watery feces, decreased fecal pH, and increased fecal VFA concentrations, without causing an inflammatory response. Daily 12-h abomasal infusions of a large dose of starch (~4 kg/d) have also induced hindgut acidosis as indicated by decreased fecal pH and watery feces. On the farm, watery or foamy feces or presence of mucin casts in feces may indicate hindgut acidosis. In summary, hindgut acidosis occurs because of relatively high rates of large intestinal fermentation, likely due to digestive dysfunction in other parts of the gut. A better understanding of the relationship of this disorder to other animal health disorders is needed.
    Journal of Animal Science 04/2011; 89(4):1120-30. · 2.09 Impact Factor
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    ABSTRACT: Previous trials with dairy ewes fed stored feeds indicate a positive effect of rumen-undegradable protein (RUP) supplementation on milk yield. However, dairy sheep production in the United States is primarily based on grazing mixed grass-legume pastures, which contain a high proportion of rumen-degradable protein. Two trials were conducted to evaluate the effects of high-RUP protein supplementation and fresh forage composition on milk yield and N utilization of lactating dairy ewes fed in confinement or on pasture. In a cut-and-carry trial, 16 multiparous dairy ewes in mid-lactation were randomly assigned to 8 pens of 2 ewes each. Pens were randomly assigned 1 of 2 protein supplementation treatments, receiving either 0.0 or 0.3 kg of a high-RUP protein supplement (Soy Pass, LignoTech USA Inc., Rothschild, WI) per day. Within supplementation treatment, pens were randomly assigned to 1 of 4 forage treatments, which were applied in a 4×4 Latin square design for 10-d periods. Forage treatments included the following percentages of orchardgrass:alfalfa dry matter: 25:75, 50:50, 75:25, and 100:0. No interactions were observed between supplement and forage treatments. Supplementation with a high-RUP source tended to increase milk yield by 9%. Milk yield, milk protein yield, milk urea N, and urinary urea N excretion increased linearly with increased percentage of alfalfa. Milk N efficiency was greatest on the 100% orchardgrass diet. In a grazing trial, 12 multiparous dairy ewes in mid lactation were randomly assigned to 3 groups of 4 ewes each. Within group, 2 ewes were randomly assigned to receive either 0.0 or 0.3 kg of a high-RUP protein supplement (SoyPlus, West Central Cooperative, Ralston, IA) per day. Grazing treatments were arranged in a 3×3 Latin square design and applied to groups for 10-d periods. Ewes grazed paddocks that contained the following percentages of surface area of pure stands of orchardgrass:alfalfa: 50:50, 75:25, and 100:0. No interactions were found between supplement and forage treatments. Milk yield, milk protein yield, and milk urea N increased linearly with increased percentage of alfalfa in the paddock. In conclusion, supplementing with high-RUP protein tended to increase milk yield and increasing the proportion of alfalfa in the diet increased dry matter intake, milk yield, and protein yield of lactating dairy ewes fed or grazing fresh forage.
    Journal of Dairy Science 01/2011; 94(1):416-25. · 2.57 Impact Factor
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    ABSTRACT: The objective of this experiment was to determine the effect of protein degradability of dairy sheep diets on milk yield and protein utilization across 2 levels of milk production. Three diets were formulated to provide similar energy concentrations and varying concentrations of rumen-degradable protein (RDP) and rumen-undegradable protein (RUP): 12% RDP and 4% RUP (12-4) included basal levels of RDP and RUP, 12% RDP and 6% RUP (12-6) included additional RUP, and 14% RDP and 4% RUP (14-4) included additional RDP. Diets were composed of alfalfa-timothy cubes, whole and ground corn, whole oats, dehulled soybean meal, and expeller soybean meal (SoyPlus, West Central, Ralston, IA). Estimates of RDP and RUP were based on the Small Ruminant Nutrition System model (2008) and feed and orts were analyzed for Cornell N fractions. Eighteen multiparous dairy ewes in midlactation were divided by milk yield (low and high) into 2 blocks of 9 ewes each and were randomly assigned within block (low and high) to 3 pens of 3 ewes each. Dietary treatments were arranged in a 3 x 3 Latin square within each block and applied to pens for 14-d periods. We hypothesized that pens consuming high-RUP diets (12-6) would produce more milk and milk protein than the basal diet (12-4) and pens consuming high-RDP diets (14-4) would not produce more milk than the basal diet (12-4). Ewes in the high-milk-yield square consumed more dry matter and produced more milk, milk fat, and milk protein than ewes in the low-milk-yield square. There was no effect of dietary treatment on dry matter intake. Across both levels of milk production, the 12-6 diet increased milk yield by 14%, increased milk fat yield by 14%, and increased milk protein yield by 13% compared with the 14-4 and 12-4 diets. Gross N efficiency (milk protein N/intake protein N) was 11 and 15% greater in the 12-6 and 12-4 diets, respectively, compared with the 14-4 diet. Milk urea N concentration was greater in the 12-6 diet and tended to be greater in the 14-4 diet compared with the 12-4 diet, indicating that the excretion of urea N in this study was more closely related to dietary crude protein concentration than to protein degradability.
    Journal of Dairy Science 10/2009; 92(9):4507-13. · 2.57 Impact Factor
  • C Leonardi, L E Armentano
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    ABSTRACT: The objectives of the present study were to compare feed selection in tie- vs. free-stall barns and also to verify possible correlations between feed selection and milk composition. Forty multiparous and 20 primiparous lactating Holstein cows were utilized in a crossover design with 21-d periods. Cows were randomly divided into 2 groups; group 1 was housed in a free-stall barn during period 1 and a tie-stall barn during period 2, and vice versa for group 2. In the free-stall barn, 18 extra cows were also present. Animals were fed the same diet once daily in the free-stall barn at 1100 h and twice daily at 1100 and 1500 h in the tie-stall barn to obtain approximately 10% daily refusals in both facilities. Group feed selection in the free-stall barn was measured and compared with the group feed selection in the tie-stall barn, obtained by summing individual feed offered and refused. Feed selection was analyzed including treatment and period in the model. Sequence effect and true error were combined into a single degree of freedom error term. Intake of the longest particles expressed as a percentage of the predicted intake was 73.2% in a tie-stall barn and 63.3% in a free-stall barn. There were no significant correlations between individual feed selection measured in the tie-stall barn and milk composition. Feed selection estimates made with individually fed cows are likely to underestimate average feed selection in a free-stall barn.
    Journal of Dairy Science 06/2007; 90(5):2386-9. · 2.57 Impact Factor
  • T F Gressley, L E Armentano
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    ABSTRACT: Post-ileal carbohydrate fermentation in dairy cows converts blood urea nitrogen (BUN) into fecal microbial protein. This should reduce urinary N, increase fecal N, and reduce manure NH3 volatilization. However, if intestinal BUN recycling competes with ruminal BUN recycling, hindgut fermentation may reduce NH3 for rumen microbial protein synthesis. Eight lactating Holstein cows were used in a replicated 4 x 4 Latin square design with 14-d periods. Treatments were arranged as a 2 x 2 factorial. Diets contained either adequate rumen-degradable protein (RDP; high RDP) or were 28% below predicted RDP requirements (low RDP). Cows received abomasal infusions of either 10 L/d of saline or 10 L/d of saline containing 1 kg/d of inulin. We hypothesized that reducing ruminal NH3, either by restricting RDP intake or by diverting BUN to feces with inulin, would reduce rumen microbial protein synthesis, as would be evidenced by significant main effects of treatments on rumen NH3, milk production, and urinary purine derivative excretion. Furthermore, we thought it likely that effects of inulin might be greater when rumen NH3 was already low, as would be indicated by significant interactions between inulin infusion and dietary RDP level on rumen NH3, milk production, and urinary purine derivative excretion. Rumen NH3 was reduced by the low-RDP diet, but urinary purine derivative excretion and milk production were unaffected. However, the low-RDP diet reduced apparent total tract digestibility of OM and starch and reduced in situ rumen NDF digestibility. Abomasal inulin reduced the BUN concentration but did not affect milk yield or rumen NH3, suggesting that RDP requirements are not affected by hindgut fermentation. Inulin shifted 23 g/d of N from urine to feces. However, based on fecal purine excretion, we estimated that only 8 g/d of the increased fecal N was due to increased fecal microbial output. Inulin reduced true digestibility of dietary protein or increased nonmicrobial as well as microbial endogenous losses. This latter effect may be an artifact of our experimental model that delivers easily fermented, soluble fiber to the small intestine. Normal dietary alterations to similarly increase large intestinal fermentation would probably arise from larger quantities of less rapidly digested carbohydrates. Increasing hindgut fermentation in practical diets should reduce manure NH3 volatilization without impairing rumen fermentation, but the reduction is likely to be small.
    Journal of Dairy Science 04/2007; 90(3):1340-53. · 2.57 Impact Factor
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    ABSTRACT: A tool was developed to aid in ruminal insertion of abomasal infusion lines into dairy cows. The tool consisted of 2 pieces cut from polyvinyl chloride pipe. The first piece of pipe, the insertion tool, contained a groove that held the flexible plastic flange that is on the end of the infusion line. The insertion tool containing the flange was inserted into the ruminal cannula, through the sulcus omasi, and into the abomasum. The second piece of pipe, the delivery tool, was threaded through the insertion tool, and it was used to dislodge the flange from the insertion tool and into the abomasum.
    Journal of Dairy Science 11/2006; 89(10):3965-7. · 2.57 Impact Factor
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    ABSTRACT: In the third in depth country study, the Babcock Institute study team discusses India’s dairy sector. India is an interesting case study because it has the world’s second largest population making it the world’s largest milk-producing country. The country’s main system of dairy productions involves a smallholder production system in which most of the milk produced is consumed on the farm or distributed through informal channels. This system of production, combined with Indian policies that encourage self-sufficiency and restrict dairy imports, leaves much unused potential in the Indian dairy market.

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  • 1985–2014
    • University of Wisconsin–Madison
      • Department of Dairy Science
      Madison, Wisconsin, United States
    • Virginia Polytechnic Institute and State University
      • Department of Dairy Science
      Blacksburg, VA, United States
  • 2011
    • University of Delaware
      • Department of Animal and Food Sciences
      Newark, DE, United States
  • 1993–2002
    • University of Wisconsin - River Falls
      • Department of Animal and Food Science
      River Falls, Wisconsin, United States
  • 1981–1984
    • Iowa State University
      • Department of Animal Science
      Ames, IA, United States