Genotype x nutritional interactions of two year old females in terms of reproductive status

Author

Harry Lee Peeler

Date of Award

12-1983

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Science

Major Professor

J.W. Holloway

Committee Members

W.T. Butts, F. David Kirkpatrick

Abstract

One hundred twenty first calf, two year old, Angus, Angus- Hereford, and Hereford females were studied over a three year period (40 each in 1981, 1982, and 1983). Females were allotted to either Kentucky 31 tall fescue (Festuca arundinacea Schreb.), legume pastures (30-40% legume), or fescue pasture. Legumes consisted of red clover (Trifolium pratense L.), Korean and Kobe lespedeza (Lespedeza stipulacea Maxim), and ladino clover (Trifolium repens L.). Forage intake and digestibility were determined from March 1 to September 21 by feeding Cr₂O₃ in a carrier feed twice daily and collecting weekly A.M. and P.M. fecal samples. Fecal samples were analyzed for calcium, chromium, dry matter, and crude fiber which were used as components to calculate dry matter (DM) intake, DM digestibility, and digestible DM intake for each female each week. Females were observed for signs of first estrus twice daily at feeding for a duration of approximately 2 hrs./feeding.

No significant interaction of breed and pasture type (P>.10) on weight and fat at first heat were detected although a trend was noticed that females were fatter at heat than at March 1. A breed of sire effect was noticed on milk production at heat with the dams of Angus sired calves on fescue pasture producing larger quantities of milk as compared to the dams with Hereford sired calves. Females on fescue-legume pastures had higher DM intakes and digestible DM intakes at heat as compared to females on fescue pastures. No significant effects (P>.10) were found with DM digestibility at heat.

Calf weight and milk production paralleled each other within each treatment. Females grazing fescue-legume with Hereford sired calves produced more milk and weaned heavier calves than dams with Angus sired calves. For fescue pastures, Angus and Angus-Hereford dams with Angus sired calves produced larger amounts of milk from day 120 to day 240 and weaned heavier calves than those with Hereford sired calves.

Recommended Citation

Peeler, Harry Lee, "Genotype x nutritional interactions of two year old females in terms of reproductive status. " Master's Thesis, University of Tennessee, 1983.
https://trace.tennessee.edu/utk_gradthes/7525