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Nutritional Supplementation to Increase Fertility and Pregnancy in Montana Yak

Naomi Redfield, Bob Sager, Department of Animal and Range Sciences, Montana State University-Bozeman, PO Box 172900, Bozeman, MT 59717

Estrus is a recurring period of sexual receptivity and fertility in females, (commonly referred to as heat). The purpose of this nutritional research on female Yaks is to test the hypothesis that increased nutrition fed for 45 days before breeding will increase estrus and therefore, increase fertility rates for a Yak herd near Kalispell, Montana.  The pregnancy rate directly influences productivity and economics in this herd. Previous fertility rates of this Yak herd had a less than 30% success in pregnancy four months after breeding. Pregnancy was determined by progesterone assay from blood collected at 4-5 months gestation. This year a custom cake ration was formulated and fed to the female Yaks 45 days before breeding and continued throughout the breeding cycle of 50 days. The custom cake feed was formulated with nutrients designed to increase estrus for the female Yaks. The cake was fed at a rate of one pound per head per day and increased at a rate of 10% weekly until an intake of 3.5 pounds was fed daily. The cake that was formulated to be composed of wheat middling (30%), corn cracked (24%), DSS (distillers solubles at 20%), molasses, a custom mineral, and soy hulls (combined at 26%). The custom mineral and cake were formulated by a nutritionist, based on a forage and water analysis from the ranch and designed to supplement the needed requirements of the female Yak.  Breeding started July 15, 2019 and continued until after September 5, 2019. Positive pregnancy testing was determined by a blood progesterone assay that was completed in December 2019. The expected increased pregnancy rates were to be a 50-60% improvement over the previous years following progesterone results. The final result from the progesterone assay was 71% of the female Yaks were pregnant.




Additional Abstract Information

Presenter: Naomi Redfield

Institution: Montana State University Bozeman

Type: Poster

Subject: Agriculture & Extension

Status: Approved


Time and Location

Session: Poster 1
Date/Time: Mon 1:30pm-2:30pm
Session Number: 2002