There is limited genetic information relating calving difficulty and body weights to other productive and reproductive traits. Such information is useful for specifying selection criteria and for predicting economic consequences of selection. Genetic, maternal, and environmental covariances of six productive and reproductive measurements with calving difficulty, birth weight, 200-d weight, and ...

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 ...

Breeding records of 40 white rhinoceros and 155 Cape buffalo were analysed. Three rhinoceros cows bred in captivity, themselves conceived for the first time at 84, 87 and 95 months of age, respectively. Rhinoceros cows breed throughout the year. There is no evidence of a relationship between calving interval and month of birth. Calving intervals were normally distributed about the mean of 34 mo...

Stayability to consecutive calvings was selected as a measure of cow longevity in the Canadian Simmental population. Calving performance data on 188,579 cows and culling information from the Total Herd Reporting System were used to determine whether a cow stayed in a herd for her second and later (up to the eighth) calvings, given that she had calved as 2 yr old. Binary records (n = 1,164,319) ...

Despite increased emphasis in recent years on declining dairy cow reproductive performance, there has been very little focus on the management of the periparturient dairy heifer and cow at calving time. Perhaps as a result, US producers are now reporting increasing perinatal calf losses at calving. A critical determinant in reducing periparturient losses is good calving management. The tenets o...

The objective of present study was to derive the economic values for number of inseminations to conception, calving interval, milk yield and stillbirth, using economic data of 10 Iranian Holstein herds. The economic values were derived by using the profit function methods and differentiating a profit equation with respect to the traits of interest. The cow fertility costs herd amortization or r...

We present results from numerical ice-flow models that include calving criteria based on penetration of surface and basal crevasses, which in turn is a function of longitudinal strain rates near the glacier front. The position of the calving front is defined as the point where either (1) surface crevasses reach the waterline (model CDw), or (2) surface and basal crevasses penetrate the full thi...

Calving records of Iranian buffaloes from April 1991 to June 2010 comprising 1,151 herds with 34,911 calving events were used to evaluate reported secondary sex ratio, stillbirth, and calf birth weight. Logistic regression models were applied to analyze stillbirth and calf sex at birth, and statistical analysis of calf birth weight was performed using a linear mixed model. Overall, the ratio of...

Reproductive efficiency in the dairy herd is the most important factor for its economic success and a major concern for dairy farmers when using artificial insemination (AI) or natural service (NS). Our objectives were to estimate, compare and analyse the costs associated with breeding cattle by do-it-yourself (DIY) AI and NS and identify the factors that influence them, under typical dairy far...