Effects of Bovine Somatotropin on Dry Matter Intake, Milk Yield, and Body Temperature in Holstein and Jersey Cows During Heat Stress
Open Access
- 1 October 1990
- journal article
- research article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 73 (10) , 2896-2906
- https://doi.org/10.3168/jds.s0022-0302(90)78977-1
Abstract
Thirty-one lactating Holstein and Jersey cows were used to determine the effect of daily injections of 0 or 20 mg of recombinant bST in hot, humid weather. The comparison period lasted 80 d, from mid-June through August. The maximum and minimum ambient temperature and relative humidity averaged 34.6 and 22.2.degree.C and 100 and 59.8%, respectively. Body temperatures of somatotropin-treated Holsteins were elevated over controls by .2 and .3.degree.C at the a.m. and p.m. milkings, respectively, whereas corresponding treatment effects for Jerseys were .5 and .6.degree.C, thus demonstrating a breed by treatment interaction. The response of milk and FCM yields and apparent efficiency of production to somatotropin administration depended on the level of production prior to treatment. Cows at low pretreatment production increased milk and FCM yields to a greater degree than did cows at higher production. A breed by treatment interaction showed that Holsteins increased milk and FCM yields more than Jerseys upon administration of somatotropin. Intake DM was not affected by treatment. Cows administered bST lost BW and condition score. Greater heat stress was associated with the higher milk production of cows administered bST.Keywords
This publication has 16 references indexed in Scilit:
- Effects of Recombinant Bovine Somatotropin on Milk Production, Body Composition, and Physiological ParametersJournal of Dairy Science, 1988
- Somatotropin and LactationJournal of Dairy Science, 1987
- Responses of Dairy Cows to Exogenous Bovine Growth Hormone Administered During Early LactationJournal of Dairy Science, 1985
- Production and Physiological Responses of Dairy Cows to Varying Dietary Potassium During Heat StressJournal of Dairy Science, 1985
- Responses of High-Producing Dairy Cows to Long-Term Treatment with Pituitary Somatotropin and Recombinant SomatotropinJournal of Dairy Science, 1985
- Effect of Growth Hormone on Milk Yields and Related Physiological Functions of Holstein Cows Exposed to Heat StressJournal of Dairy Science, 1985
- A Dairy Cow Body Condition Scoring System and Its Relationship to Selected Production CharacteristicsJournal of Dairy Science, 1982
- The primary structure of bovine growth hormoneFEBS Letters, 1973
- Section A. Physiology. Cattle in a hot environmentJournal of Dairy Research, 1965
- Prediction of the Energy Value of Cow's MilkJournal of Dairy Science, 1965