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...

a total of 260709 monthly test day milk records of 30903 first lactation holstein cows was used to determine the best function to describe the lactation curve. the records were obtained from first lactation holstein of 216 herds from 1988 to 2006 in khorasan province. the functions used in current study were wood’s incomplete gamma function, ali and schaeffer function, and legendre function of ...

In the present study, records on 22872 first-parity Holsteins collected from 131 herds by the Animal Breeding and Improvement Center of Iran from 1995 to 2014 were considered to estimate genetic and phenotypic relationships between calving difficulty (CD) and the lactation curve traits, including initial milk yield (Ap), ascending (Bp) and descending (Cp) slope of the lactation curves, peak mil...

the main objective of the present study was to explore the feasibility of nonlinear mixed models to describe the somatic cell score (scs) lactation curves and to compare the fit of four nonlinear vs. two linear models when applied to scs lactation records in iranian holstein cows. the animal breeding center of iran provided the scc data. the data consisted of 445077 test-day observations from 6...

the base of this review is to consider the relevant role that animal factors (potential milk yield, body weight, body condition score, state of lactation, parity and fertility) play on milk performance (considering the energy balance and the rumen function across the full lactation curve of animals) and milk quality (milk protein content, milk fat content, milk lactose content, vitamins, minera...

test day records of first lactation holstein cows from 1996 to 2008 were obtained from animal breeding center of iran and used in this research. data consisted of 872125 test-day milk records of 95816 cows from 59 herds. (co)variance components and genetic parameters were estimated using random regression model via gibbs sampling method. two order legendre polynomials and third coefficient of w...