EFFECTS OF HIGH-STARCH DIETS ON RUMINAL EFFICIENCY AND WOOL GROWTH

1984 ◽  
Vol 64 (5) ◽  
pp. 179-180 ◽  
Author(s):  
P. I. HYND ◽  
W. G. ALLDEN
Keyword(s):  
Key Words ◽  
Rumen Fermentation ◽  
Direct Proportion ◽  
Protein Nitrogen ◽  
Wool Growth ◽  
Intestinal Digestion ◽  
High Starch ◽  
Protein Supply

Sheep consuming similar amounts of a high-barley diet exhibited wide differences in rumen fermentation patterns and in the quantity of protein-nitrogen available for intestinal digestion. Wool growth varied in direct proportion to the postruminal protein supply. Key words: Sheep, concentrates, protein flow, wool growth

scholarly journals The effect of patterns of rumen fermentation on the response by dairy cows to dietary protein concentration

1990 ◽  
Vol 63 (2) ◽  
pp. 177-186 ◽  
Author(s):  
J. A. Lees ◽  
J. D. Oldham ◽  
W. Haresign ◽  
P. C. Garnsworthy
Keyword(s):  
Dairy Cows ◽  
Milk Fat ◽  
Starch Content ◽  
Live Weight ◽  
Lactation Performance ◽  
Protein Nitrogen ◽  
High Starch Content ◽  
High Fibre ◽  
High Starch ◽  
Protein Supply

Four groups of seven dairy cows were given hay plus high-fibre concentrates based on sugar-beet feed (hay-concentrate, 40:60 w/w) or high-starch concentrates based on flaked maize (hay-concentrate, 20:80 w/w), with a crude protein (nitrogen x 6.25) content of either 160 or 220 g/kg dry matter, over weeks 4–18 of lactation. Performance during week 3 of lactation, when all cows were fed on a standard ration, was used as a covariate. For diets with a high-fibre content, higher protein concentrations led to increases in yields of milk and milk fat, with no effect on live-weight loss. For diets with a high-starch content, higher protein concentrations did not affect milk yield or composition but resulted in an increase in live weight rather than a decrease. Diets with a high-starch content led to increased proportions of propionic acid in the rumen and increased concentrations of insulin in the blood. It is concluded that the source of carbohydrate needs to be taken into account when predicting the response to protein supply by dairy cows.

The rumen fermentation of lactose in the adult sheep

1961 ◽  
Vol 57 (2) ◽  
pp. 267-270 ◽  
Author(s):  
D. M. Walker ◽  
Barbara A. Lee
Keyword(s):  
Skim Milk ◽  
Rumen Fermentation ◽  
Enzymic Activity ◽  
Lactase Activity ◽  
Protein Nitrogen ◽  
Adult Sheep

1. A cross-bred sheep was fed successively with supplements of dried skim-milk or lactose. The effect of the supplements on the lactase activity of the rumen liquid was followed.2. Lactase activity was expressed as mg. lactose hydrolysed per ml. rumen liquid, or per mg. protein nitrogen. The enzymic activity fluctuated considerably after a change in the diet, and did not become constant even when the ration remained the same for 7 weeks.

Rice polishings as an alternative to sugar cane molasses as a supplement with urea to low-quality forage diets for ruminants

1993 ◽  
Vol 56 (1) ◽  
pp. 85-92 ◽  
Author(s):  
D. Cardenas Garcia ◽  
C. J. Newbold ◽  
H. Galbraith ◽  
J. H. Topps ◽  
X. B. Chen ◽  
...  
Keyword(s):  
Sugar Cane ◽  
Dry Matter ◽  
Volatile Fatty Acids ◽  
Latin Square ◽  
Experimental Period ◽  
Rumen Fermentation ◽  
Cane Molasses ◽  
Mean Values ◽  
Rumen Ph ◽  
Protein Supply

AbstractThe effect of including 14 g urea with either 75 g dry matter (DM) from sugar cane molasses (UM) or Colombian rice polishings (RP) at three levels, 68 (RP1), 137 (RP2) or 203 (RP3) g DM on grass hay DM intake and on rumen fermentation was investigated. An incomplete Latin-square design was used and each experimental period was divided into 12 days for adaptation to each diet followed by 9 days in metabolism cages when all measurements were made using five adult sheep.Pooled mean values for rumen metabolites (five samples per day) were calculated. Rumen pH was not affected by the nature of the supplements. Concentrations of volatile fatty acids (VFA) (UM 92·8, RP1 84·2, RP2 86·4, and RP3 84·0 (s.e.d. 3·4) mmol/l) and lactate (UM 2·0, RP1 1/6, RP2 1/7, RP3 1/8 (s.e.d. 0·014) mmol/l) (UM v. RP, P < 0·05 and P < 0·10 respectively) were lower when RP were given, while concentration of branched and longer chain VFA (26·5, 34·0, 31·1 and 33·5 (s.e.d. 1·6) mmol/mol total VFA, UM v. RP, P < 0·01) and ammonia (98, 131, 141, 137 (s.e.d. 16·1) mg/l, UM v. RP, P < 0·05) were increased. Numbers of rumen protozoa (1·6, 3·2, 2·7, 3·3 (s.e.d. 0·75) × 105 per ml, UM v. RP, P < 0·20) tended to be higher 2 h after feeding when RP rather than UM were given. However, hay DM intake (1050, 960, 960, 880 (s.e.d. 45·3) g/day, UM v. RP, P < 0·05), and microbial protein supply (11·7, 9·3,11·1,10·8 (s.e.d. 0·59) g N per day, UM v. RP, P < 0·05), estimated from urinary purine excretion were reduced by feeding RP instead of UM.At the levels of inclusion tested RP did not increase the efficiency of rumen fermentation and were not as effective a supplement with urea as was molasses for a low-quality forage diet.

Do more mechanistic models increase accuracy of prediction of metabolisable protein supply in ruminants?

2019 ◽  
Vol 59 (11) ◽  
pp. 1991
Author(s):  
Michael S. Allen
Keyword(s):  
Dietary Protein ◽  
Mechanistic Models ◽  
Microbial Protein ◽  
Components Separation ◽  
Protein Nitrogen ◽  
Diet Formulation ◽  
Ruminal Degradation ◽  
True Protein ◽  
Accuracy Of Prediction ◽  
Protein Supply

Ruminal microbes partially degrade dietary protein and synthesise microbial protein, which, along with undegraded true protein, contributes to metabolisable protein for the animal. Rumen models have been developed over the past several decades in an effort to better predict metabolisable protein supply for ration formulation for ruminants. These models have both empirical and mechanistic components. Separation of dietary protein into fractions that include non-protein nitrogen, true protein and unavailable protein has been a fundamental element of these models. Ruminal degradation of one or more true protein fractions is then estimated on the basis of the kinetics of digestion and passage. Some models use the same method to predict substrate supply for microbial protein production. Although mechanistic models have been extensively used in diet-formulation programs worldwide, their ability to improve accuracy of prediction of metabolisable protein over simpler empirical models is questionable. This article will address the potential of mechanistic models to better predict metabolisable protein supply in ruminants as well as their limitations.

Sign in / Sign up

Export Citation Format

Share Document