to estimate heritability and genetic trend for 305-d milk production and lactation persistency, a total of 130,668 monthly test day milk yields belonging to 15,183 first lactation holstein cows in 131 herds and calved from 2000 to 2009 were used. to calculate 305-d milk yield as well as lactation persistency, estimated parameters of wilmink’s exponential function were applied. the parameters of...

the objectives of this study were to 1) describe the risk factors, incidence, production and reproduction consequences of retained placenta in dairy cows, and 2) estimate the financial losses associated with retained placenta. calving records from march 2008 to december 2013 comprising 59,341 calving were included in the data set. the effects of risk factors on retained placenta incidence were ...

The study aimed to determine factors affecting the dry period length and effect of dry days on milk yield, milk composition and lactation length in the next lactation of dairy cows. Data used for analysis included 7264 lactation records collected from 2012 to 2016 on 4737 Holstein cows raised in 152 herds. The statistical model used to determine the factors influencing the dry period length sho...

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...

In this study, maternal effects were described as age of dam at first and second calving, first-lactation body condition score (BCS) of the dam during gestation, and milk yield of the dam. The impact of these effects on first-lactation daughter BCS, fertility, and test-day milk yield was assessed. The effect of milk yield of dam on daughter 305-d yield in the latter's first 3 lactations was als...

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...

The objectives were to estimate (co)variance components and genetic parameters for lactation curve traits in Holstein dairy cows in Iran. The used data were records on Holstein cows collected during January 2003 to December 2012 by the Animal Breeding Center of Iran (Karaj, Iran). In order to describe the lactation curve, an incomplete gamma function was fitted to 691200 test-day records on 962...

the objective of this study was to investigate the effect of inbreeding on lactation performance in holstein cows of iran.the pedigree file contained information of 1,025,281 animals born between 1965 and 2007.lactation performance records from march 2000 to april 2009 comprising 193,501calving events on 123,751 cows in 85 dairy herds were included in the data set. the potential consequent effe...

The objective of this study was to investigate the effect of milking frequency (two times daily vs. three times daily) on the 305-d lactation milk, fat and protein yield and fat and protein percentage of Holstein dairy cows in Morocco. Data analyzed were 31400 records collected between 2009 and 2016 on 14272 cows raised in 194 herds. The frequency of milking had significant effects (P<...