Corn gluten meal or dried brewers grains as partial replacement for soybean meal in the diet of Holstein cows.

Abstract Holstein cows (n = 24, 9 primiparous) were assigned equally to diets based on corn silage and high moisture corn supplemented with soybean meal alone or with either corn gluten meal or dried brewers grains. In diets with two protein sources, the protein quantity from each source was similar. Dietary CP and ADF averaged 16.3 and 18.8%, and undegraded protein as a percentage of CP was 33.6, 41.1, and 41.8% for the respective diets. After parturition. COWS were fed the soybean meal diet for a 3-wk covariant period, an experimental diet for 10 wk, the soybean meal diet for 3 wk, and the experimental diet for another 10 wk. Milk production by cows fed those diets averaged 30.9, 31.7, and 34.9 kg/d; protein averaged .90, .94, and 1.02 kg/d; and DMI averaged 16.8, 18.8, and 18.2 kg/d, respectively, for the two 10-wk periods. No dietary differences occurred for 3.5% FCM, estimated DM digestibility, BW, BW gain, or percentages of milk fat, protein, or SNF. Ruminal isobutyrate and isovalerate differed by diet; isovalerate was highest in the diet containing soybean meal plus corn gluten meal, probably because of the high Leu content of corn gluten meal. Ruminal NH 3 N did not differ. The favorable production response by cows fed dried brewers grains can be explained by a more favorably balanced AA profile in the ruminally undegraded protein than in other diets

A blend of animal and cereal protein or fish meal as partial replacement for soybean meal in the diets of lactating Holstein cows.

Abstract Six replications in Experiment 1 and four replications in Experiment 2 of a 3 × 3 Latin square arrangement of treatments were used to compare soybean meal or soybean meal partially replaced with fish meal or a protein blend for response in intake, milk yield and composition, ruminal NH 3 N, blood urea, and ruminal fermentation in lactating Holstein cows. The blend contained 30% corn gluten meal, 30% poultry by-products, 30% blood meal, and 10% feather meal. Periods were 28 d, and the first 7 d were used for adjustment. In addition to these protein sources, diets contained corn silage, alfalfa haylage, dried cracked corn, ground barley plus added fat, and a mineral and vitamin mixture. In Experiment 1, mean DMI was 24.4kg, mean milk yield was 36.7kg, mean fat percentage was 3.48%, and mean milk protein percentage was 3.06%; there were no significant differences. In Experiment 2, DMI was different for soybeans (22.6kg) versus other sources (21.4kg), but milk yield (32.1kg) and fat (3.39%) and protein (2.87%) percentages did not differ among diets. In Experiment 1, ruminal NH 3 N was greatest for cows consuming soybean diets (11.0 mg/dl) and lowest for cows consuming diets containing the protein blend (8.7 mg/dl). No differences in VFA were found. The lack of response to RUP can be explained by a rather high intake of a fermentable diet, which supplied sufficient absorbable AA according to the Cornell AA model

IN-SITU RUMINAL DISAPPEARANCE OF ESSENTIAL AMINO-ACIDS IN PROTEIN FEEDSTUFFS

Four protein sources were incubated in situ to estimate AA disappearance. Bags containing either soybean meal, corn gluten meal, herring meal, or meat meal were washed in water or suspended in the rumen of two Holstein cows for 8, 12, 16, 24, 48, 72, and 120 h. Cytosine, a bacterial marker for microbial contamination, was used to correct the essential AA profile for microbial contribution to determine the residual essential AA composition of the protein sources after incubation. Ruminal disappearance of individual essential AA was different among feedstuffs. Relative to original feed protein, soybean meal and corn gluten meal decreased the concentration of specific essential AA in the RUP. Concentration of all essential AA, except Arg and His, increased in undegraded meat meal protein. The difference between original and residual AA concentrations in herring meal approached statistical significance. Use of the original AA profile of the feed protein to predict essential AA available for absorption is not accurate because accuracy differs with sources

Comparison of fibrous materials as modifiers of in situ ruminal degradation of corn gluten meal

Abstract Degradability of corn gluten meal protein in situ is grossly underestimated compared with in vivo measurements. To study the influence of corn gluten meal mixed with different fibrous sources on in situ ruminal DM and CP degradation, bags containing meal alone or mixed with corn cobs, wheat straw, or sawdust, respectively, were suspended in the rumen of two lactating Holstein cows for 0, 4, 12, 24, 48, 72, or 120 h. The three fibrous sources also were incubated alone to determine their degradation pattern. Cytosine was used as a bacterial marker to correct the in situ residues for bacterial contamination. Sawdust was almost completely resistant to ruminal degradation, and straw was slowly degraded to a final extent of 35.3% of total DM. The DM in corn cobs had a degradable fraction of 63.7% and a rate of disappearance higher than that of corn gluten meal incubated alone. The DM and CP degradation rates of meal were not modified when feed was mixed with corn cobs. Incubation with straw and sawdust increased rate of disappearance of DM and CP of corn gluten meal (2.1 and 1.2%, respectively). Ruminal turnover was assumed to be 6%h, and CP degradabilities of corn gluten meal were 30.6 and 25.1% when the feed was incubated with straw and sawdust, respectively