This study was carried out in a commercial herd from 2008 to 2012 in order to determine the most prevalent reasons for culling Holstein cows and to assess the effects of risk factors. Overall, 519 (28.2%) cows were culled for involuntary (98.8%) and voluntary (1.2%) reasons. The involuntary causes of culling were diseases (38.7%), reproduction problems (36.0%), udder disorders (7.7%), lameness ...

This experiment was conducted to evaluate the association between risk factors and the risk of culling in Iranian Holstein cows. The data consisted of 329,772 lactation records obtained from the Animal Breeding Center of Iran (2003 - 2012) and logistic regression was applied to investigate the associations between the predictor and response variables. The response variable in this experiment wa...

This study was performed to estimate the effect of age at first calving and first two calving intervals on productive life and life time profit in Korean Holsteins. Reproduction data of Korean Holsteins born from 1998 to 2004 and lactation data from 276,573 cows with birth and last dry date that calved between 2000 and 2010 were used for the analysis. Lifetime profit increased with the days of ...

A total of 245187 records of the first three lactations of 131126 Holstein cows in tropical conditions were used to estimate the genetic (co)variance components between age at calving and its respective milk productions. A multivariate analysis of six traits was performed. Heritability for age at calving (h2AC) and milk yield (h2MY) decrease from the ...

The objective of this study was to evaluate calving intervals and repeatability of calving intervals of young beef cows when breeding seasons were initiated immediately after calving. Average calving date at 2, 3, and 4 yr of age was recorded, and duration of calving interval between the first and second and second and third parities was compared in 178 crossbred beef cows calving between 1981 ...

in this research, buffalo production was studied from view points of housing, feeding, milk production and reproducrion in rural area of shoushtar, khuzestan. the results of this study revealed that in a herd 66.7 , 8.3 and 25 % were breeders (adult females), adult bulls and valves. each breeder female buffalo had 3-17 parturation in whole life. first service was done at 18 month after birth an...

 In US dairy herds, the current national average age at first calving is 25.2 months. Increasing first-lactation milk yield could improve milk’s life-cycle production efficiency and decrease emissions.  The productive life of dairy Holsteins in the United States born in 2000 decreased by 3.95 months compared with Holstein cows born in 1980. This negative trend needs to be halted to achieve en...