Effects of Previous Days Open, Previous Days Dry, and Present Days Open on Lactation Yield
نویسندگان
چکیده
منابع مشابه
Effects of twinning on lactation and days open in Holsteins.
Effects of twinning on lactation and days open in Holsteins were studied from calving records compiled by member surveys of Eastern Artificial Insemination Cooperative. Records of cows with 305-day mature-equivalent records from the Northeast Dairy Records Processing Laboratory were grouped according to whether the twin calving was associated with dystocia. Records of each cow that had a twin c...
متن کاملMethodology for estimation of days dry effects.
The primary objective of this research was to determine if, with appropriate methodology, unbiased estimates of days dry (DD) effects on subsequent lactation milk yield can be obtained from field data, particularly when DD is correlated with cow effects. Another objective was to ascertain relevant sampling properties of designed trials for estimation of DD effects. Simulated records were used t...
متن کاملgenetic analysis of milk yield and open days traits of holstein dairy cattle in iran for first five lactation
a data file containing 607662 (317608) milk (open days) records belonging 294417 (177838) holstein cows that were calved from 1983 to 2008 was used. the bivariate repeatability model was used for data analyzing so that herd, calving year, calving month, days in milk (only for milk trait) and calving age for each parity, were assumed as fixed effects and additive genetics and permanent environme...
متن کاملUse of early lactation days open records for genetic evaluation of cow fertility.
National genetic evaluations for cow fertility were introduced by the USDA in February, 2003. These evaluations, reported as daughter pregnancy rate, are based on days open. One requirement of the evaluation system is that lactations be at least 250 d in milk (DIM) to be included for analysis. The objective of this research was to develop a predictor of days open, usable in genetic evaluation, ...
متن کاملLung Function before and Two Days after Open-Heart Surgery
Reduced lung volumes and atelectasis are common after open-heart surgery, and pronounced restrictive lung volume impairment has been found. The aim of this study was to investigate factors influencing lung volumes on the second postoperative day. Open-heart surgery patients (n = 107, 68 yrs, 80% male) performed spirometry both before surgery and on the second postoperative day. The factors infl...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1987
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(87)80297-7