Genomic merit for reproductive traits. II: Physiological responses of Holstein heifers
نویسندگان
چکیده
منابع مشابه
Physiological Responses to Des in Heifers
The purpose of this study was to determine the influence of diethylstilbestrol (DES) and differing nutritional regimens on respiratory and heart rates, electrocardiogram (EKG) patterns, rectal temperature and blood lactic acid values of steers. Sixteen Angus steers were fed a 75% concentrate diet ad ffbitum for a 28-day standardization period. Eight steers were then fed 20 mg DES per steer per ...
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The objective of the current study was to evaluate the effects of supplement type on performance, reproductive, and physiological responses of grazing yearling beef heifers. Sixty Brahman x British crossbred heifers were stratified by initial body weight (BW) and age, and randomly allocated to 12 pens (five heifers/pen). Pens were randomly assigned to one of two treatments: 1) molasses-based su...
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This experiment compared growth, body composition, plasma IGF-I and leptin, and reproductive development of beef heifers receiving or not recombinant bovine ST (BST) beginning after weaning until the first breeding season. Fifty Angus × Hereford heifers (initial BW = 219 ± 2 kg; initial age = 208 ± 2 d), weaned at approximately 6 mo of age, were assigned to the experiment (d 0 to 210). On d 0, ...
متن کاملEvent-time analysis of reproductive traits of dairy heifers.
Data on the reproductive traits of dairy heifers were analyzed using event-time techniques. Traits analyzed were age at first calving (n = 4631), days to first breeding, and days open (n = 1992) during the first lactation. A proportional hazard model was used that included fixed effects of herd-year, year-season, breed type, herd weight, and heifer weight. Body weights were recorded at 390 d of...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2019
ISSN: 0022-0302
DOI: 10.3168/jds.2018-15245