Metabolic Modifiers Effects on the Nutrient Requirements of Food-Producing Animals (1994) / Chapter Skim
Currently Skimming:
3. Effect of Somatotropin on Nutrient Requirements of Dairy Cattle
3. Effect of Somatotropin on Nutrient Requirements of Dairy Cattle
Pages 23-29
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 23... ...
cows supplemented with bST are like genetically superior cows at the same level of milk production, and (3) cows supplemented with bST should be fed according to level of production using current National Research Council (NRC)
|
From page 24... ...
The effect of bST on milk fat and protein composition clepends on the nutritional status of the cows both before and during bST treatment (Peel and Bauman, 1987; McBride et al., 1988; Bauman et al., 1989a; Chalupa and Galligan, 1989; van clen Berg, 1989, 1991; Dell'Orto and Savoini, 1991; Barbano et al., 1992; Laurent et al., 1992; Lynch et al., 19921. In the early stages of bST treatment, increases in milk fat and decreases in milk protein may occur whenever milk-yield increases cause changes in energy and protein balance in the cow such that body fat and protein stores are mobilized to meet the increased nutrient demands.
|
From page 25... ...
Feed Intake Production responses to bST have been obtained under a wide variety of feeding programs inclucling feeding total mixed rations, fee(ling grain and forage separately, and pasture-fedcows. Aparticularlyimportant adaptation is that cows typically adjust their voluntary feed intake upward within a few weeks after initiation of bST treatment (Peel and Bauman, 1987; Chalupa and Galligan, 1989; Chilliard, 19891.
|
From page 26... ...
that bST treatment does not alter the digestibility of dietary dry matter, energy, or carbon (Peel et al., 1981, 1985; TyrreD et al., 1988; Sechen et al., 1989a; Kim et al., 1991; Kirchgessner et al., 1991a; Lynch etal., 1991; Robinson et al., 19911. Bioenergy studies demonstrate that the energy requirements for maintenance and milk production are not altered in bST-treated cows (Tyrrell et al., 1988; Sechen et al., 1989a; Kirchgessner et al., 1991a)
|
From page 27... ...
As milk production increases, a substantial amount of adclitional dietary protein from protein supplements must escape rumen fermentation to meet the cow's requirement for protein. The current recommendations for protein requirements of lactating cows include both a percentage of rumen clegracled protein, to allow for maximum microbial growth and digestion of fiber, and a percentage of undegradable protein that will escape ruminal degradation and augment the supply of essential amino acids that can be absorbed from the small intestine (National Research Council, 1988b)
|
From page 28... ...
(199lb) also demonstrated that replenishment of body reserves was less adequate as the dietary ratio of forage-concentrate was increased; these results are consistent with earlier work and the fact that their design based the dietary shifts on stage of lactation rather than level of milk yield or body condition scores.
|
From page 29... ...
Restoration of body condition is more efficient in late lactation than during the ciry period; however, if cows are not in proper body condition at (fry-off, then (fry cow management should be aimed at replenishing reserves prior to calving. Economics and management strategies may indicate that with higher levels of milk production and changes in persistency obtained with the use of bST, longer calving intervals may be appropriate.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.