| Autor: |
Salfer JA; Department of Animal Science, University of Minnesota, St. Paul 55108., Linn JG, Otterby DE, Hansen WP, Soderholm CG |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of dairy science [J Dairy Sci] 1994 Aug; Vol. 77 (8), pp. 2367-75. |
| DOI: |
10.3168/jds.S0022-0302(94)77179-4 |
| Abstrakt: |
We studied the effect of increased energy density of diets during early lactation on lactational performance of cows injected with bST. Total mixed rations contained 50% forage (DM) and 2.5% choice white grease during the first 14 wk of lactation. Thirty cows were fed diets with grease as the only supplemental fat, and 15 cows were fed grease plus 1.8% calcium salts of long-chain fatty acids. One-half of the cows fed grease and all cows fed grease plus calcium salts of long-chain fatty acids received 640 mg/28 d of sustained-release bST from 6 to 44 wk postpartum. Calcium salts of long-chain fatty acids did not increase milk yield, 3.5% FCM, or DMI during the first 14 wk postpartum or during 15 to 44 wk postpartum. Administration of bST increased milk fat concentration .4% units during the first 14 wk postpartum. Cows receiving bST had higher DMI and produced 18.5% more 3.5% FCM from 15 to 44 wk postpartum than did controls. Calcium salts of long-chain fatty acids or bST injections did not influence body condition score or BW. These data suggest that cows yielding 30 to 35 kg of milk/d during the first 14 wk of lactation may not respond to added fat over 2.5%. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
|
