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Biomedical subjects

L D Satter

Publications and source records attributed to L D Satter.

At least 73 records · Page 4Linked to original sources
PubMed1983

Retention time in rumen and degradation of protein supplements fed to lactating dairy cattle.

In part 1 of this experiment, six lactating Holstein cows were used to determine rate of passage of soybean meal, corn gluten meal, and brewer's dried grains through the gastrointestinal tract and also to compare chromium-ethylenediaminetetraacetic acid and cobalt-ethylenediaminetetraacetic acid as liquid digesta markers. Cows were offered a basal diet containing 60% alfalfa hay and 40% of a grain mix twice daily. In addition, all cows received 2.7 kg daily of a mixture of soybean meal, corn gluten meal, and brewer's dried grains. At a designated feeding, each of the protein supplements was labeled with a separate rare earth marker element (samarium, cerium, or lanthanum). Mean ruminal turnover of liquid was 11.4 and 9.9%/h when chromium-ethylenediaminetetraacetic acid and cobalt-ethylenediaminetetraacetic acid were used as markers. Treatment means for ruminal turnover of soybean meal, corn gluten meal, and brewer's dried grains were 4.9, 5.3, and 4.8%/h. In part 2, nitrogen disappearance from soybean meal, corn gluten meal, and brewer's dried grains placed in Dacron bags suspended in the rumen of a fistulated cow was determined at intervals of 1, 4, 8, 12, 16, and 24 h. These measurements, along with information on the amount of protein supplement remaining in the rumen at various intervals (derived from the rate of passage data), were used to estimate protein degradability in the rumen. Protein degradabilities by this approach for soybean meal, brewer's dried grains, and corn gluten meal were 72, 42, and 14%. Results for soybean meal and brewer's dried grains matched in vivo results in the literature, but corn gluten meal was underestimated grossly.

Animals↗
PubMed1983

Influence of nonprotein nitrogen and protein of low rumen degradability on nitrogen flow and utilization in lactating dairy cows.

Four lactating cows, each fitted with a rumen cannula and duodenal and ileal t-cannulae, were used to measure flow and digestion of nitrogenous compounds in the digestive tract. Dietary dry matter contained 17% crude protein and 50:50 forage:concentrate. Treatments were: 1) corn silage-soybean meal; 2) corn silage-heated soybean meal; 3) ammonia-treated corn silage-soybean meal; and 4) ammonia-treated corn silage-heated soybean meal. Flow of organic matter to the duodenum was overestimated when lanthanum or chromium ethylene-diaminetetraacetate was used as an indigestible marker. This resulted in low estimates of ruminal digestion of organic matter and high estimates of nitrogen flow to the duodenum. However, calculations using lanthanum or lignin as markers yielded similar organic matter flow to ileum and feces. With acid-detergent lignin as a marker, estimates of dietary nitrogen degraded in the rumen were: corn silage-heated soybean meal, 55.0% ammonia-treated corn silage-heated soybean meal, 58.8%; ammonia-treated corn silage-soybean meal, 63.3%; and corn silage-soybean meal, 66.0%. Digestion in the small intestine of nonammonia nitrogen was equal for all treatments suggesting that availability of heated soybean meal in the intestine was not different, although ruminal degradability tended to be lower. Feeding diets containing nonprotein nitrogen did not decrease available nitrogen at the duodenum.

Animals↗
PubMed1978

Influence of dietary protein concentration on milk production by dairy cattle during early lactation.

In a 3 X 2 factorial experiment 75 Holstein cows in first, second, or third lactation were fed rations containing either 12.2% or 16.2% crude protein in total ration dry matter. On the average, 26% of dry matter intake was from corn silage, 22% from alfalfa-grass hay, and 52% from a grain mix. Protein was controlled by feeding a 13.7% crude protein grain mix with 1.4% urea for the 12% ration and a 19.8% crude protein grain mix with natural protein for the 16% ration. Average daily milk production (kg/day) for wk 2 through 12 of lactation for 12% and 16% rations by lactations were: first, 21.6 and 21.9; second, 25.7 and 31.5; and third, 27.5 and 34.0. Dry matter intakes by lactations were .42, 1.18, and 2.05 kg/day higher for cows fed the high protein compared to low protein rations. Milk composition was not influenced by protein treatment. The markedly different response to protein supplementation in milk production between heifers in first lactation and more mature cows is unexplained.

Aging↗
PubMed1976

Relationship between ruminal ammonia and nonprotein nitrogen utilization by ruminants. III. Influence of intraruminal urea infusion on ruminal ammonia concentration.

In three trials, we studied the effect of incremental amounts of intraruminally infused urea on mean ruminal ammonia concentration of steer fed at 2-h intervals. Basal rations contained these percentages of crude protein and total digestible nutrients (dry matter basis); Trial I, 11.1 and 81; Trial II, 6.0 and 54; Trial III, 6.5 and 58. Mean ruminal ammonia concentration reached 5 mg ammonia nitrogen/100 ml rumen fluid at crude protein equivalents of 12.0, 9.3, and 9.4% in I, II, and III. Once ruminal ammonia began to accumulate, there was a linear relationship between intake of urea and mean concentration of amino acids of plasma, serving as an indirect measure of amino acid absorption from the intestine, was not increased by increased intake of urea in III. Results of this experiment support the concept from in vitro data that microbial protein synthesis is unaffected by ruminal ammonia concentration in excess of 5 mg ammonia nitrogen/100 ml rumen fluid.

Amino Acids↗
PubMed1976

Response to lactating dairy cows to abomasal infusion of amino acids.

Essential amino acids most limiting for milk production and/or secretion of milk protein were determined in five trials involving infusion of amino acids into the abomasum of lactating Holstein cows. Cows were fed corn-based rations containing 10.7 to 11.5% crude protein (dry matter basis) which exceeded standard allowances for energy. All trials were Latin-square designs with 9-day periods. The abomasal infusion of methionine had no effect on secretion of milk, milk protein, or milk fat. Lysine infusion resulted in 16% of the total response in yield of milk protein that was obtained with either the 10 essential amino acids or sodium caseinate while infusion of lysine and methionine together accounted for 43% of the total response. This suggested that lysine and methionine were first and second limiting, or co-limiting, for secretion of milk protein when rations consisting primarily of corn, corn silage, and alfalfa-grass hay were fed. The primary effect was on content of milk protein rather than milk yield. In general, amino acid infusions had no effect on feed intake, milk fat, and nonprotein nitrogen content of milk. Little change occurred in concentrations in plasma of other amino acids when lysine and methionine were infused together. When concentrations were lowered, indicating increased protein synthesis, changes were too small to be statistically significant.

Abomasum↗
PubMed1976

Protein and methionine hydroxy analog for lactating cows.

A 2 X 2 factorial experiment (protein 12.5 and 15.5; methionine hydroxy analog 0 and .125% dry matter) included 144 cows for one complete lactation, distributed over seven locations. Rations were formulated to the desired protein, methionine analog, and constant amounts of fiber 17%, sulfur .225%, calcium .6%, phosphorus .4%, and salt .5%. Treatment effects were not apparent for dry matter intake, daily milk and fat-corrected milk production, conversion of energy, and body weight changes. Conversion of dietary crude protein into milk protein was 34.5% for the low and 25.8% for the high protein ration. Methionine analon (0% = 2.54; .125% = 1.90). Effect of methionine analog was most apparent at low protein as 0 analog cows produced 247 kg fat, required 2.9 services/contraception, and had 156 days open whereas cows on other treatments (.125% analog and/or high protein) produced 264 kg fat, required 1.8 to 2.2 services/conception, and had 124 to 134 days open. Methionine analog response is discussed in relation to tuminal and postruminal effects as well as the interrelation with protein and energy.

Animals↗
PubMed1975

Adverse effect of excess methionine or methionine hydroxy analog on feed consumption in cattle.

The toxicity of DL-methionine and methionine hydroxy analog infused into the rumen or abomasum was gauged by relative feed consumption. A continuous intraruminal infustion of at least 3 days' duration of DL-methionine equalent to about 2.5% or more of dietary dry matter intake was required to reach a toxic amount. This was approximately four times the amount necessary when it was infused into the abomasum. Methionine hydroxy analog equalent to about 1% or more of dietary dry matter intake was toxic when infused into either rumen or abomasum. This is in large excess of suggested amounts of analog supplementation. Reduced palatability is likely to occur in advance of reduced intake due to toxicity.

Abomasum↗
PubMed1975

Nitrogen requirement and utilization in dairy cattle.

Formulation of dairy cow rations should consider the following points regarding nitrogen utilization by lactating cows. (a) Maintenance of ruminal ammonia nitrogen in excess of 5 mg/100 ml rumen fluid has no effect on microbial protein production. (b)Supplemental nonprotein nitrogen is not utilized in typical dairy and feedlot beef rations containing more than 12 to 13% crude protein(dry matter basis). (c)Nonprotein nitrogen is approximately equal to true protein as a source of nitrogen in typical dairy and feedlot rations containing not more than 12 to 13% crude protein. (d)A scheme based upon metabolizable protein (absorbable protein) for calculating requirements and comparing protein sources is superior to crude or digestible protein designations. Ultimate expression of the requirement may be in terms of crude protein for the sake of simplicity. (e)One kilogram of crude protein, regardless of nitrogen source, equals about .75kg metabolizable protein in typical dairy and feedlot beef rations containing not more than 12 to 13% crude protein. One kilogram of plant protein (true protein) fed in excess of an amount equivalent to 12 to 13% dietary protein equals about .3 kg metabolizable protein. (f)Protein supplementation of lactating cows might be related more to stage of lactation than to milk production. (g)Lactating cows having above average lactational ability may benefit from dietary protein as high as 16 to 17% (dry matter basis) during the first third of lactation. (h)Cows in the latter two-thirds of lactation appear to require 12.5% dietary protein or less. (i)Plant protein (true protein) should be the supplemental sources of nitrogen during the first third of lactation, with NPN providing most, if not all, the supplemental nitrogen during the last two-thirds of lactation.

Ammonia↗
PubMed1975

Relationship between ruminal ammonia and nonprotein nitrogen utilization by ruminants. I. Development of a model for predicting nonprotein nitrogen utilization by cattle.

The influence of ration composition on mean ruminal ammonia concentration was studied by collecting samples of ruminal ingesta from cattle fed rations varying in crude protein and total digestible nutrient content. A minimum of four sampling times distributed throughout the day permitted calculation of mean ruminal ammonia concentrations. Mean ruminal ammonia concentration was positively related to dietary crude protein concentration and negatively related to total digestible nutrient concentration. It is postulated that mean ruminal ammonia concentration may be a useful criterion for predicting efficacy of nonprotein nitrogen supplementation. A quantitative approach for evaluating nonprotein nitrogen supplementation based upon determination of the point at which ruminal ammonia exceeds the requirement (5 mg ammonia nitrogen/100 ml rumen fluid) of the ammonia-utilizing bacteria is proposed. Dietary conditions expected to result in excessive concentrations of ruminal ammonia are defined and recommended upper limits for nonprotein nitrogen supplementation are presented. Theoretical relationships between composition of the unsupplemented ration, amount of nonprotein nitrogen added, and efficiency of nonprotein nitrogen utilization are discussed. The practice of adding nonprotein nitrogen so as to exceed 12 to 13% crude protein in typical dairy or feedlot rations needs to be reevaluated.

Ammonia↗
PubMed1975

Relationship between ruminal ammonia and nonprotein nitrogen utilization by ruminants. II. Application of published evidence to the development of theoretical model for predicting nonprotein nitrogen utilization.

Results from published experiments dealing with several aspects of nitrogen utilization by ruminants were used to test the concept of zero utilization of nonprotein nitrogen under conditions where more ammonia (greater than 5 mg ammonia nitrogen/100 ml) is in the rumen than can be converted to microbial protein. Results from experiments where the flow of non-ammonia nitrogen to the abomasum of sheep was measured indicate that when urea was the source of supplemental nitrogen, a constant quantity of amino acids reached the abomasum for all rations ranging from 10 to 23% crude protein. From growth studies, addition of nonprotein nitrogen to low protein, high energy rations caused an improved rate of gain. Additions of nonprotein nitrogen to rations resulting in predicted ruminal ammonia concentrations greater than 5 mg ammonia nitrogen/100 ml rumen fluid were without benefit. From lactation studies, nonprotein nitrogen supplementation did not improve milk production if the ration contained more than 12.5% crude protein prior to supplementation or if the predicted ruminal ammonia concentration was greater than 4 mg ammonia nitrogen/100 ml rumen fluid. The importance of the amino acid requirement of the animal as well as the composition of the ration in designing and evaluating nitrogen supplementation studies is discussed.

Ammonia↗