Genetic Effects on Stillbirth and Calving Difficulty in Swedish Holsteins at First and Second Calving

The Effect of Age at First Calving and Calving Interval on Productive Life and Lifetime Profit in Korean Holsteins

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 ...

Genetic parameters for calving difficulty, stillbirth, and birth weight for Hereford and Charolais at first and later parities.

The aim of this study was to estimate direct and maternal genetic parameters for calving difficulty score, stillbirth, and birth weight at first and later parities for Charolais and Hereford cattle in Sweden. Calving traits have long been recorded for pure-bred beef cattle in Sweden, but only birth weight has been used in the selection in order to avoid calving difficulties. Linear animal model...

Calving day and age at first calving in Angus heifers.

Because of difficulties in data collection and analysis, in most breeds there have been limited ways to evaluate fertility in females on a between-herd basis. The objective of this study was to determine the heritabilities (direct and maternal) for CD (calving day) and AFC (age at first calving) in American Angus heifers and to evaluate the potential for using these traits in genetic improvemen...

Reducing Calving Difficulty in Simmental

Many factors contributed by calf, dam and sire are associated with CD and many of these are interrelated. Deutscher (1988) came to the conclusion that "the primary cause of CD in young cows is due to a disproportion between size of calf (birth weight) and size of birth canal (pelvic size) of the cow." The relationship of these two factors are presented in the figure below quoted by Deutscher (1...

Calving Difficulty in Beef Cattle