LACTATION PERFORMANCE OF HIGH-YIELD FIRST-CALF COWS
نویسندگان
چکیده
منابع مشابه
Cubic-spline interpolation to estimate effects of inbreeding on milk yield in first lactation Holstein cows
Milk yield records (305d, 2X, actual milk yield) of 123,639 registered first lactation Holstein cows were used to compare linear regression (y = β(0) + β(1)X + e), quadratic regression, (y = β(0) + β(1)X + β(2)X(2) + e) cubic regression (y = β(0) + β(1)X + β(2)X(2) + β(3)X(3) +e) and fixed factor models, with cubic-spline interpolation models, for estimating the effects of inbreeding on milk yi...
متن کاملHeritability Estimates for First Lactation Milk Yield of Registered and Nonregistered Holstein Cows
Heritabilities of milk yield and fat test were estimated from first lactation records of 196,672 Holstein daughterdam pairs separately for registered and nonregistered cows for four milk yield groups and by years of freshening of the daughter. The model included herdseason and sire of the daughter. Heritability estimates were similar for registered and nonregistered cows averaging about .33 for...
متن کاملMATERNAL PERFORMANCE OF FIRST-CALF CROSSBRED BEEF COWS IN RELATION TO SIRE EXPECTED PROGENY DIFFERENCES (EPDs)
Cumulative milk production of crossbred daughters of sires of several breeds was estimated using weigh-suckle-weigh procedures. Pooled-across-breed analyses were conducted to determine, in retrospect, relationships of sire expected progeny difference (EPD) values for milk and total maternal value to daughter milk yield and daughter's offspring weaning weight. The pooled coefficient for regressi...
متن کاملEffect of Milking Frequency on the Lactation Performance and Lactation Curve of Holstein Dairy Cows in Iran
The aim of this study was to investigate the effect of milking frequency (three times daily vs. two times daily) on the lactation curve shape, partial and 305-d lactation performance in Holstein dairy cows in Iran. Data from February 2000 to December 2012 comprising 217345 lactations on 141364 cows distributed in 324 herds collected by the Animal Breeding Center of Iran were used. The mean milk...
متن کاملFirst-lactation performance in cows affected by digital dermatitis during the rearing period.
The long-term effects of prepartum digital dermatitis (DD) on first-lactation performance were evaluated in a cohort of 719 pregnant heifers. All heifers were followed for a period of 6 mo until calving and classified on the basis of the number of DD events diagnosed during this period as type I, type II, or type III (no DD, one DD event, and multiple DD events, respectively). Health during the...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Siberian Herald of Agricultural Science
سال: 2018
ISSN: 0370-8799
DOI: 10.26898/0370-8799-2018-2-7