introduction cattle are a monotocous species meaning that, under most circumstances, a successful pregnancy results in the birth of one calf. twinning rate has been reported in dairy cows from 3 to 5 percent, which can be influenced by maternal age.the birth of twins is detrimental to the majority of beef and dairy cattle producer. financial loss arising from any of twinning has been reported i...

Longevity and lifetime productivity are important factors influencing profitability for the cow-calf producer. Heifers that conceive earlier in the breeding season will calve earlier in the calving season and have a longer interval to rebreeding. Calves born earlier in the calving season will also be older and heavier at weaning. Longevity data were collected on 2,195 heifers from producers in ...

A 5-yr study was conducted beginning in 1983 with 460 cows to evaluate the effects of three breeding seasons (30, 45, and 70 d in length) and two times of spring calving, March (early) and April (late), on cattle production under Nebraska Sandhills range conditions. Criteria evaluated included pregnancy and weaning percentages, calving date and distribution, cow weights and body condition at fo...

economic data and performance records from 10 iranian holstein dairy cattle herds, as well as milk production and fertility records from iranian center of animal breeding and animal production improvment were used to estimate the effect of calving difficulty on milk production, fertility and as well on the economic aspects of maternal and direct calving difficulty. calving difficulty could be d...

Genetic parameters for birth weights (BWT), calving ease scores observed from calves born by heifers (CEH), and calving ease scores observed from calves born by cows (CEC) were estimated using Bayesian methodology with Gibbs sampling in different threshold animal models. Data consisted of 77,458 records for calving ease scores and birth weights in Gelbvieh cattle. Gibbs samplers were used to ob...

The Australian dairy herd size has doubled over the last 20 years substantially increasing the time that farmers require for individual animal attention to monitor and intervene with events such as calving. Technology will help focus this limited labour resource on individual cows that require assistance. The objective of this experiment was to first determine the profiles of rumination duratio...

Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The appli...

The aim of this study was to determine the factors affecting stillbirth and the consequences of stillbirth on longevity, production, and reproductive performance in Holstein cows of Iran. Calving records from March 2000 to April 2009 comprising of 220,043 calvings on 102,199 cows in 33 herds were used. The results showed that 4.06% of the newborn calves died within 48 h of birth. The stillbirth...

The association of birth type (single vs. double) and pregnancy type (single vs. double) with lactation performance and lactation curve was investigated in Holstein cows in Iran. Data of 243298 lactations on 138021 cows in 261 herds collected during January 2000 to December 2012 were used. The average twinning rate was 3.64% and ranged from 1.44% (primiparous) to 5.41% (multiparous). Factors as...