The effects of beef cow milk yield and composition on calf growth and cow reproduction

Date

1998-12

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

During 1997 and 1998, purebred Angus cows were evaluated in three separate trials at the Texas Tech Beef Center. In 1997, the cows in this study were randomly separated into two groups and supplemented with cottonseed meal, extruded whole cottonseed and extruded cull cottonseed at three different time periods. The cows were milked during each period of the trial. Cow and calf weights were analyzed as well as milk yield and composition. The following year, these same cows were fed a commercial direct-fed microbial. These cows were again separated into two groups and milked throughout the trial. Cow and calf weights, milk yield, milk fat, milk crude protein and somatic cell count were analyzed. The third trial conducted analyzed the effects of milk yield in Angus cows on udder conformation, teat measurements and reproduction. Milk yields were collected each year as well as udder conformation scores. Reproduction was recorded by analyzing the time period between calving and first artificial insemination dates. Results form the first trial showed an increase in milk yield (P < .05) when extruded protein supplements were fed. Cows that were fed cottonseed meal also gained more weight than those fed extruded products. When the direct-fed microbial was fed during the second trial, cow weight gain showed to have increased (P < .05) during two of the five milkings. Percent milk fat as well as somatic cell count were also increased (P < .05). In the third and final trial, results showed that milk yield does statistically effect reproduction as well as udder confirmation traits. A negative correlation was also recognized on first artificial insemination interval when analyzed against milk EPD's for 1995.

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