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W Chalupa

Publications and source records attributed to W Chalupa.

At least 19 recordsLinked to original sources
PubMed2006

Short communication: Further validation of the fat sub-model in the Cornell-Penn-Miner Dairy model.

Recently, a fat sub-model was introduced into the Cornell-Penn-Miner Dairy model (CPM-Dairy; Moate et al., 2004). The principal aim of the work reported here was to validate this fat sub-model in terms of its accuracy in predicting the apparent absorption (intake - feces) of total long-chain fatty acids (LCFA) in lactating dairy cows. The fat sub-model in CPM-Dairy was used to predict the amounts (g/d) of total LCFA apparently absorbed from 63 diets described in 14 published experiments. These predicted amounts (PLCFA) were regressed against the amounts reported to be apparently absorbed (RLCFA). The regression equation was: PLCFA = - 24.8 +/- 25.2 + 1.011 x 0.029 x RLCFA; R2 = 0.95, RMSE = 55.2 g/d. The results show that for a diverse range of diets, the fat model in CPM-Dairy can accurately predict apparent absorption of dietary total LCFA.

Abomasum↗
PubMed2005

Effects of BioChlor and Fermenten on microbial protein synthesis in continuous culture fermenters.

Meta analysis models were constructed from a data-set of 15 continuous culture fermenter trials and 118 observations on studies with either BioChlor (n = 23 observations) or Fermenten (n = 95) included at 10 and 3%, respectively, of dietary dry matter (DM) to evaluate effects of the ingredients BioChlor and Fermenten (B/F) on rumen function. Digestibility of crude protein was significantly increased by 11% with B/F treatment. This was reflected in significant increases in digestibility of DM and organic matter (OM) by 3.6 and 7.9%, respectively. Increased amounts of sugar in the diet in the presence of B/F tended to reduce digestibility of non-structural carbohydrates (NSC); however, the net effect on NSC digestion was small. There was no effect of treatment on most individual volatile fatty acids (VFA) or total VFA production. Propionate production, however, was significantly reduced in treated fermenters. The main effect of B/F as well as of starch and soluble fiber when combined with the treatment was to increase propionate production; however, the interaction between B/F treatment and sugar decreased propionate production markedly, resulting in a net decrease. The acetate-to-propionate ratio increased by 6% with B/F, largely as a result of the decrease in propionate. Production of nonammonia nitrogen was 1% less in B/F-treated fermenters, and interactions between treatment and starch, sugar, or soluble fiber were significant. Treated fermenters produced 15.7% more microbial nitrogen, in association with a significant 37% increase in rumen protein digestion. Interactions between treatment and starch, soluble fiber, or sugar influenced these results. The interaction of B/F and sugar resulted in a decrease in undegradable protein N and an increase in microbial nitrogen production. Ammonia nitrogen concentrations were increased by 24.6% in treated fermenters. Efficiency of microbial nitrogen production from DM, OM, or carbohydrate was significantly increased by B/F. Sugar content increased efficiency of microbial protein production/kg of OM digested or carbohydrate digested in the presence of treatment by >10 times the increase that was attributable to the interaction of treatment with starch. Treatment with B/F reduced moles of VFA produced/kg of microbial nitrogen produced by 16%. This effect was also substantially influenced by interactions between B/F and sugar. If the fermenter results are representative of those in vivo, milk production responses to treatment with B/F will depend on amounts of starch, soluble fiber, and, particularly, sugar in diets. Milk production responses will also depend on the quality of protein in the diet and the comparative benefit that increased flux of microbial nitrogen provides. Increased digestibility of OM should allow additional ruminant production benefits.

Amino Acids↗
PubMed2000

Influence of abomasal infusion of high levels of lysine or methionine, or both, on ruminal fermentation, eating behavior, and performance of lactating dairy cows.

Four multiparous late-lactation Holstein cows were fed a basal ration designed to be co-limiting in intestinally absorbable supplies of methionine and lysine. Cows were supplemented with no amino acids, lysine by abomasal infusion to 140% of the calculated intestinally absorbable requirement, methionine by abomasal infusion to 140% of requirement, or both amino acids in a 4 x 4 Latin square design with 28-d periods. Unsupplemented cows consumed 23.8 kg/d of dry matter and produced 36.9 kg/d of milk containing 3.70% fat, 3.22% protein, and 4.82% lactose. Cows ate less dry matter and produced less milk and milk lactose, and tended (P = .06 or .08) to produce less milk protein when abomasally infused with methionine alone or together with lysine. Infusion of lysine alone resulted in production values numerically between those of unsupplemented cows and those cows supplemented with methionine alone or together with lysine. Evaluation of the results with two metabolic models of dairy cows indicated that performance of unsupplemented cows may have been limited by delivery of metabolizable or digestible protein, or intestinally absorbable lysine, isoleucine, or histidine, depending on the metabolic model used to evaluate animal performance. Regardless, results are consistent with those using nonruminant species, which have shown that imbalanced profiles of intestinally absorbable amino acids are associated with reduced dry matter intake and animal performance. Results also show that negative effects on performance of lactating dairy cows can occur if methionine is supplied at levels substantially in excess of calculated intestinally absorbable requirements, either alone or together with lysine.

Abomasum↗
PubMed1999

Influence of postruminal supplementation of methionine and lysine, isoleucine, or all three amino acids on intake and chewing behavior, ruminal fermentation, and milk and milk component production.

Four multiparous Holstein cows were fed a basal diet balanced with the Cornell Net Protein and Carbohydrate System (CNCPS). Diets were formulated to be co-limiting in intestinally absorbable supplies of methionine, lysine, and isoleucine. Cows were supplemented with no amino acids (control); lysine and methionine in a ruminally protected form; isoleucine by abomasal infusion; or lysine, methionine, and isoleucine in a 4x4 Latin square arrangement of treatments with 28-d periods. Performance of cows on all treatments was lower than expected due to low intake of DM that could have been caused by the high fiber level of the basal diet. This high fiber level was likely responsible for the high daily chewing times for cows fed all diets, which was consistent with the high ruminal pH values. Intake of DM and its components were not influenced by any treatment. Milk protein percentage tended to be higher when cows were fed diets supplemented with ruminally protected lysine and methionine; however, production of milk, milk fat, and milk lactose were not affected by any treatment. Cows tended to have a higher milk lactose proportion and tended to produce more milk and milk lactose when they were abomasally infused with isoleucine alone. However, when cows were supplemented with all three amino acids, milk production and composition did not differ from that of cows fed the unsupplemented diet. Use of the CNCPS to evaluate the performance of the cows fed the unsupplemented diet suggested that these cows may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and methionine in addition to metabolizable protein. Evaluation of the unsupplemented diet with an alternate model, Shield, suggested that cows fed the unsupplemented diet may have been colimited by intestinally absorbable supplies of lysine, isoleucine, and arginine. Results suggest that enhanced delivery of intestinally absorbable isoleucine may stimulate milk lactose synthesis.

Animal Feed↗
PubMed1998

The effect of ruminal bypass lysine and methionine on milk yield and composition of lactating cows.

Fifty-six multiparous Holstein cows were assigned at 3 wk prepartum to rations based on grass silage with 1) corn distillers grains to provide 86 and 90% of estimated required metabolizable Lys and Met, respectively; 2) a blend of blood meal, fish meal, and meat and bone meal as amino acid (AA) sources to provide 112 and 103% of required metabolizable Lys and Met, respectively; 3) ruminally protected Lys and Met added as a top-dressing to ration 1 to provide 27 g/d of Lys and 8 g/d of Met as available AA at the duodenum postpartum; and 4) ruminally protected AA for 8 wk postpartum as a top-dressing to ration 1 to provide 40 g/d of Lys and 13 g/d of Met as available AA at the duodenum. Cows fed rations 3 and 4 were offered 13.5 g/d of duodenally available Lys and 4 g/d of duodenally available Met for 3 wk prepartum. The total length of the study was 43 wk. Cows fed ration 4 consumed 3 to 4 kg more dry matter than did cows fed the other three rations, and milk yield and the percentage of milk protein and fat were significantly increased during the first 8 wk of lactation. In early lactation, cows fed ration 3 had a greater milk fat percentage but similar dry matter intake, protein percentage, and yield of 4% fat-corrected milk compared with cows fed ration 2. The concentrations of blood serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, triglyceride, and nonesterified fatty acids were lower for cows fed ration 4 during the first 8 wk of lactation than they were for cows fed the other three rations. The mammary arteriovenous difference of whole blood AA indicated that Met along with His and Arg may be the most limiting AA for milk yield.

Amino Acids↗
PubMed1998

Ruminally protected lysine or lysine and methionine for lactating dairy cows fed a ration designed to meet requirements for microbial and postruminal protein.

The purpose of this study was to separate the effects of ruminally protected Lys from effects of ruminally protected Met on the performance of lactating dairy cows fed a ration calculated to be first-limiting in intestinally delivered Lys and second-limiting in intestinally delivered Met. Thirty multiparous Holstein cows were examined in a 20-wk study that started on wk 5 postpartum. Rations contained timothy silage, corn silage, barley, corn, corn gluten meal, and soybean meal. Treatments were 1) no supplemental amino acids, 2) 21 g/d of intestinally available Lys, and 3) 22 g/d of intestinally available Lys and 6 g/d of intestinally available Met. Post-experimental calculations suggested that, in contrast to the objective, the unsupplemented ration was colimiting in intestinally available His (0.96 of requirement), followed by Lys (1.00), digestible ruminally undegraded protein (1.01), Ile (1.03), Arg (1.04), Val (1.10), and Met (1.14). In this context, the virtually identical performance of cows fed the unsupplemented ration and cows fed the ration supplemented with ruminally protected Lys demonstrated that dairy cows did not respond to enhanced intestinal supplies of Lys when Lys was not calculated to be the first-limiting nutrient. In contrast, for cows fed rations supplemented with both ruminally protected Lys and ruminally protected Met, the production of both milk protein (40 g/d) and fat (40 g/d) was numerically increased to an extent that was consistent with earlier reported studies, although calculations did not indicate that performance was limited by intestinal supplies of Lys or Met. This result, which may be disputed because of a lack of statistical significance, suggests that Met, apparently unlike Lys, may enhance the production of milk components beyond an enhancement expected because of its role as a limiting amino acid.

Animals↗
PubMed1996

Responses of dairy cows supplemented with somatotropin during weeks 5 through 43 of lactation.

Beginning at wk 5 of lactation, 136 cows (34 per treatment) were supplemented daily for 38 wk with 0, 10.3, 20.6, or 41.2 mg of recombinantly derived bST monomer. Cows were obtained from University of Kentucky, University of Minnesota, University of Pennsylvania, and The Ohio State University. Nine cows (4 at 0 mg/d, 1 at 10.3 mg/d, 1 at 20.6 mg/d, and 3 at 41.2 mg/d) did not complete the experiment because of health problems. Data from these cows were included in the reproduction and health databases but not in the production database. Cows supplemented with bST produced more milk, consumed more feed, had lower rates of BW gain, and had improved efficiencies of milk production (conversion of feed and NEL to milk). Additional increases in productivity were modest at 20.6 and 41.2 mg/d versus productivity at 10.3 mg/d of bST. Concentrations of fat, protein, and TS in milk were unaffected. At 10.3 mg/d, bST did not adversely affect reproduction or health.

Animal Nutritional Physiological Phenomena↗
PubMed1995

Ruminally protected lysine and methionine for lactating dairy cows fed a diet designed to meet requirements for microbial and postruminal protein.

Dairy cows, 20 at each of two sites, were used to determine responses to ruminally protected Lys and Met in a full lactation study. Cows were fed corn silage twice daily for ad libitum intake and a concentrate four times daily in proportion to milk production. At Truro, cows were fed 2.7 kg/d of alfalfa and timothy hay DM at 0600 and at 1500 h. At Fredericton, cows were fed 2.7 kg of timothy silage DM at 0600 h and 2.7 kg of alfalfa hay DM at 1500 h. Diets were designed to meet, but not to exceed, recommendations for ruminally degradable CP and intestinally digestible protein. Ten cows at each site were fed ruminally protected L-Lys.HCl (19 g/d) and DL-Met (6.5 g/d). Cows fed AA at each site produced more milk, lactose, protein, and fat; milk protein and fat percentages were also higher. No time x treatment interactions occurred for any production parameter. In spite of similar production responses between sites, cows fed AA consumed more DM at Truro, but those at Fredericton did not. Thus, gross efficiency of utilization of dietary N for milk N was increased with AA at Fredericton but not at Truro. However, considering the increased intake of CP by cows fed AA at Truro, an event that would have been expected to depress efficiency of utilization of dietary N, the lack of difference at Truro between treatments can be interpreted as an improvement, relative to expectations, because of AA feeding. High producing dairy cows fed a diet that was adequate in CP responded to ruminally protected Lys and Met primarily with increased production of milk protein and fat throughout the full lactation.

Animals↗
PubMed1995

Responses in urea and true protein of milk to different protein feeding schemes for dairy cows.

Four multiparous Holstein cows were used in a 4 x 4 Latin square to investigate the effects of protein concentration, degradability, and quality on plasma urea concentration and milk N constituents. Diets varied in the amount and proportion of RDP and RUP relative to NRC requirements: diet 1, excessive RDP, deficient RUP; diets 2 and 3, balanced for RDP and RUP; and diet 4, excessive RDP, balanced for RUP. Diet 3 was formulated for optimal AA balance as predicted by the Cornell Net Carbohydrate and Protein System. Diets contained 34% corn silage, 19% alfalfa haylage, and 49% concentrate (DM basis). Concentrates varied in amounts of urea and soybean, corn gluten, and fish and blood meals. Concentrations of urea N and NPN in milk varied among diets: diet 1, 19 and 34 mg/dl; diet 2, 16 and 31 mg/dl; diet 3, 15 and 30 mg/dl; and diet 4, 23 and 39 mg/dl, respectively. Increases in NPN concentration were attributed to increases in the urea fraction of NPN. Intake of RUP and AA balance influenced milk true protein content; diet 1, 2.89%; diet 2, 2.90%; diet 3, 3.01%; and diet 4, 2.95%. the proportions of true protein and urea in milk are influenced by CP concentration, protein type, and protein quality.

Animal Feed↗
PubMed1993

A net carbohydrate and protein system for evaluating cattle diets: IV. Predicting amino acid adequacy.

The Cornell Net Carbohydrate and Protein System was modified to include an amino acid submodel for predicting the adequacy of absorbed essential amino acids in cattle diets. Equations for predicting the supply of and requirements for absorbed essential amino acids are described and presented. The model was evaluated for its ability to predict observed duodenal flows of nitrogen, nonammonia nitrogen, bacterial nitrogen, dietary nonammonia nitrogen, and individual essential amino acids. Model-predicted nitrogen, nonammonia nitrogen, bacterial nitrogen, and dietary nonammonia nitrogen explained 93.2, 94.6, 76.4, and 79.3% of the observed duodenal flows, respectively, based on R2 values from predicted vs observed regression analysis. Based on slopes of regression lines, model-predicted duodenal nitrogen and nonammonia nitrogen were different from observed duodenal flows (P < .05), whereas model-predicted bacterial nitrogen and dietary nonammonia nitrogen were not different from observed duodenal flows (P < .05). Model-predicted duodenal flows of individual essential amino acids explained 81 to 90% of variation in observed duodenal amino acid flows. Based on slopes of regression lines, model-predicted duodenal threonine, leucine, and arginine were the only amino acids different from observed duodenal flows (P < .05). Ideas for further model improvements and research in amino acid metabolism were also presented.

Absorption↗
PubMed1991

Protein and amino acid nutrition of lactating dairy cattle.

This article describes the National Research Council Model of protein metabolism and illustrates its use in meeting the protein requirements of lactating cows. Attention is then directed toward amino acid nutrition with emphasis on the need for models to estimate amino acid requirements. Finally, the potential to improve productivity with rumen-protected amino acids is considered.

Amino Acids↗
PubMed1990

Responses of dairy cows in early lactation to bovine somatotropin and ruminally inert fat.

Bovine somatotropin (0 or 41.2 mg/d bST) and calcium salts of long-chain fatty acids (0 or .77 kg/d Ca-LCFA) were administered to 16 Holstein cows in early lactation. Cows remained on 0 or 41.2 mg/d bST for the entire 10 wk and received 0 or .77 kg/d Ca-LCFA in one of two 5-wk periods. Production data were recorded daily, milk fatty acids, and blood metabolites were determined once each period. Treatments did not affect feed intake. Fat-corrected milk (kg/d) and percentage of milk fat for cows receiving no supplementation, fatty acids alone, bST alone, and fatty acids and bST together were 33.8, 3.2; 33.5, 3.1; 37.4, 3.4; and 40.8, 3.5. Milk fatty acids below C16 were reduced with either bST or dietary fatty acids; C16 fatty acids were lower with bST but higher with dietary fatty acids; C18:0 fatty acids were reduced with dietary fatty acids; and C18:1 fatty acids were higher with either bST or dietary fatty acids. Blood acetoacetate concentrations were higher with both bST and dietary fatty acids, beta-hydroxybutyrate was not different, and FFA and insulin concentrations increased with bST. In this experiment, the energy supplied by Ca-LCFA acids enhanced the lactogenic effect of bST.

3-Hydroxybutyric Acid↗
PubMed1990

Effect of dietary crude-protein type on fertilization and embryo quality in dairy cattle.

An experiment was conducted to determine whether balancing dietary crude protein for optimal rumen degradability would improve fertilization rate and quality of ova in lactating dairy cows. Thirty-eight Holstein cows in early lactation were fed 1 of 2 diets formulated to be isocaloric and isonitrogenous, containing 16% crude protein. Diet 1 contained 73% rumen degradable intake protein, whereas diet 2 contained 64% rumen degradable intake protein. The cows were induced to superovulate and were inseminated, and ova were recovered nonsurgically on postbreeding day 7. Ova were counted and classified as fertilized or unfertilized. Fertilized ova were scored as excellent, good, fair, poor, or degenerate. Unfertilized ova and poor and degenerate embryos were considered to be nontransferable ova and excellent, good, and fair embryos were considered to be transferable ova. There were no differences for mean number of fertilized, unfertilized, transferable, or nontransferable ova recovered from cows fed the 2 diets (P greater than 0.10). Mean percentage of fertilized ova recovered from cows was greater (P less than 0.05) in those fed diet 2, compared with diet 1. Mean percentage of transferable ova recovered from cows tended to be greater (P = 0.06) in those fed diet 2, compared with diet 1. More cows failed to yield transferable ova (P less than 0.05) when fed diet 1, compared with diet 2. Fertilization failure or early degeneration of embryos may occur in cows fed excess rumen degradable protein.

Animal Feed↗
PubMed1989

Impact of protein nutrition on reproduction in dairy cows.

In most but not all published studies, feeding diets with high concentrations of crude protein decreased reproductive efficiency. We were able to resolve some of the inconsistencies among published reports by considering the fate of consumed protein in the rumen and then using logistic regression analysis to identify factors affecting pregnancy. Our models showed that type and amount of protein fed explained much of the variation in conception rate. Age and dietary concentration of energy were identified as modifiers of the impact of protein on reproduction. Protein nutrition can affect reproduction through toxic effects of ammonia and its metabolites on gametes and early embryos, through deficiencies of amino acids, and by exacerbations of negative balances of energy. Alterations in the hypothalamic-hypophyseal-ovarian axis may be responsible for many of the effects of protein on reproduction.

Animal Feed↗
PubMed1989

Nutritional implications of somatotropin for lactating cows.

Milk yield, feed intake, physiology, health, and reproduction of cows supplemented with somatotropin are like those of genetically superior cows. Lactation curves are shifted upward and are more persistent. Holsteins, Jerseys, Brown Swiss, and Ayrshires respond. In most cases, responses in primiparous and multiparous animals are similar. Milk composition, ration digestibility, maintenance requirements, and the partial efficiency of lactation are not affected by somatotropin. More nutrients are directed to milk synthesis. Initially, body stores of fat, protein, and glycogen provide these nutrients, but after a few weeks, feed intake increases. Cows supplemented with somatotropin should be fed like high producing cows. When ration energy density is increased by feeding grain, buffers such as sodium bicarbonate should be included to prevent alterations of hydrogen balance in the rumen and tissues. Ration energy density can also be increased with ruminally inert fat like calcium salts of fatty acids. Rations should be balanced for rumen degradable and undegradable protein. Rations for high milk yields are expensive, but income over feed costs are greater. Cows should be moved to rations with lower nutrient densities on the basis of body condition and milk yield. Current feeding recommendations can be used for cows supplemented with somatotropin.

Animal Feed↗
PubMed1989

Effect of food deprivation on D-xylose absorption test results in mares.

A D-xylose absorption test was conducted on 4 healthy mares deprived of food for 12, 36, 72, and 96 hours before the test, with a 13- to 15-day adjustment period between each test. Maximal plasma concentrations after 72 and 96 hours of food deprivation were approximately 36% lower than those obtained after the 12- and 36-hour periods (P = 0.0001). Absorption curves were flatter and the decrease in plasma concentration was slower after the 72- and 96-hour periods of food deprivation. The rate of D-xylose absorption (P = 0.0108) and the initial rate of urinary excretion (P = 0.0117) were slower at 72 and 96 hours. Gastric emptying appeared to be progressively delayed with food deprivation, as evident by the delay in peak D-xylose excretion in urine (P = 0.0268). Areas under the plasma concentration-time curves and quantitites of D-xylose excreted in urine were similar for all periods of food deprivation, evidence that the same amounts of D-xylose were absorbed, despite changes in the plasma curve. A 15-hour collection period was sufficient to recover all D-xylose excreted in the urine, and during all periods 9.8 +/- 0.6% (mean +/- SEM) of the oral dose was eliminated in the urine.

Animal Feed↗
PubMed1988

Response to elemental sulfur by calves and sheep fed purified diets.

Free amino acid profiles in plasma and liver as well as body, organ and gastrointestinal growth were compared in 20 weanling bulls (four per treatment) fed diets deficient (.04%), excessive (.94 and 1.72%) or adequate (.34%) in S. Body, organ and gastrointestinal comparisons also were made with yearling rams fed .04 and .34% S diets. The .34% S diet was fed at two levels, one ad libitum, the other in amounts equal on a body weight.75 basis to that consumed by animals fed the .04% S diet ad libitum. Animals were allowed to consume other diets ad libitum. The calves fed the .04% S diet had negative S, but slightly positive N, balance and were unable to maintain body weight. As dietary S content was increased, plasma and liver methionine increased linearly. An increased histidine in plasma of calves fed the .04% S diet may be due to reduced intake because the calves restricted-fed the .34% S diet also had high plasma histidine. Plasma citrulline, cystine, serine and total nonessential amino acids decreased markedly as dietary S intake became adequate. Intermediate S diets resulted in reduced concentrations of plasma alanine, serine, proline and total nonessential amino acids. Calves restricted-fed the .34% S diet were the most efficient in retaining N with less urinary N. Excesses of S were not detrimental to growth, but plasma valine increased linearly as S intake increased. The S deficiency in calves reduced the ratio of the rumen-reticulum tissue to body weight, and in rams it reduced the ratio of gastrointestinal tissue and preintestinal tissue to body weight. Per kilogram of intestinal-free body weight, there was a linear decrease in liver and testes but an increase in adrenals as S was decreased for calves. The kidney, adrenals and pituitary were increased by S deficiency in rams. Of the amino acids assayed, only methionine from the plasma and liver in calves reflected both an excess and a deficiency of S independent of feed intake effects.

Amino Acids↗