Data from a survey performed from 1986 to 1990 were analyzed to assess the effects of diseases on length of productive life of 3589 Holstein cows from 47 herds, using a proportional hazard model. The probability of a cow being culled, or hazard function, was supposed to be the product of an unspecified baseline hazard function and log-linear, time-dependent explanatory variables that possibly i...

Data on 657 lactation from 163 Maltese goat, collected over a 5-year period were analyzed by a mixed model to estimate the variance components for heritability. The considered lactation traits were: milk yield (MY) and lactation length (LL). Year, parity and type of birth (single or twin) were significant sources of variation for lactation length; on the other hand milk yield was significantly ...

Effects of lactation length and weaning-to-conception interval on the subsequent litter size of purebred sows were estimated using an animal model. Data on 2,847 Landrace sows with 7,125 litters born between January 1989 and May 1997 and on 1,234 Yorkshire sows with 2,999 litters born between January 1990 and May 1997 were obtained from two Canadian selection herds. Sows having a lactation of l...

OBJECTIVE The aim of the current study was to describe the relationship between milk yield and lactation number, stage, length and milking frequency in Korean Holstein dairy cows using an automatic milking system (AMS). METHODS The original data set consisted of observations from April to October 2016 of 780 Holstein cows, with a total of 10,751 milkings. Each time a cow was milked by an AMS ...

The study was conducted to estimate the genetic and phenotypic correlations among body measurements, body weight, kidding interval, kidding rate and milk yield in the different breeds of goat. Data was collected on 95 goats of three breeds (Jamunapari, Black Bengal and their crosses (Jamunapari×Black Bengal) through direct observation. The average body weight of Jamunapari goat was 34.75 ± 3.33...

Inheritance of economic traits was studied in Nili-Ravi dairy buffaloes through analysis of data comprising 5037 records of daughters of 79 sires. Data were collected from three large-sized state dairy farms. Heritability, genetic and phenotypic correlations of some indicator traits on important production and reproduction traits were worked out. Based upon analysis of records for first lactati...

the objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (afc), calving interval (ci) and somatic cell count (scc) in iranian holstein cows. the dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from july 2002 to september 2007 in a total of 9...

Sample day records of means of somatic cell scores were analyzed to develop adjustments to standardize records for length of lactation. Estimates for effect of DIM were from a model that included random lactation and cow effects for lactations to date of 753,929 Holsteins and 21,842 Jerseys calving in Pennsylvania or Wisconsin from 1987 to 1991. Lactation, cow, and residual variances were estim...

Knowledge of genetic parameters is essential for improved reproductive management and increased yield. Quantitative analysis of genetic parameters is lacking for many breeds of buffaloes. This article provides the first estimate of genetic parameters for dual purpose (meat and milk) Brazilian Jaffarabadi buffaloes, using Bayesian inference. Data on milk yield (MY), lactation length (LL), weight...