Author
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SUMMERS, ADAM - UNIVERSITY OF NEBRASKA |
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Cushman, Robert - Bob |
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CUPP, ANDREA - UNIVERSITY OF NEBRASKA |
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Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only Publication Acceptance Date: 3/5/2012 Publication Date: 7/1/2012 Citation: Summers, A.F., Cushman, R.A., Cupp, A.S. 2012. Heifers with low antral follicle counts have low birth weights and produce progeny with low birth weights [abstract]. Journal of Animal Science. 90 (Supplement 3):680 (Abstract #702). Interpretive Summary: Technical Abstract: Research has demonstrated that heifers with increased numbers of ovarian antral follicle counts (AFC) have improved hormonal profiles and improved fertility. Interestingly, heifers with low AFC had lower birth weights, suggesting that genes influencing growth and development also influence the development of the reproductive tract and establishment of the ovarian reserve. To determine the relationship of AFC to heifer BW, reproductive tract characteristics, and first calf performance, composite (MARC III x Red Angus) heifers (n= 362) were used over a 4 yr period. In yr 1 heifers grazed winter range or corn stalk residue and were offered no supplement or 0.45- 0.90 kg/d (31%CP, DM Basis) during development. In yr 2 and 3 heifers grazed winter range and were fed a dried distillers grain-based (DDG) or corn gluten feed-based supplement offered at 0.59% and 0.78% BW, respectively, throughout development. Supplements were formulated to be isocaloric but differed in undegradable protein. In yr 4 heifers were fed either 0.59% or 0.46% BW of the DDG based supplement offered in yr 2 and 3. All heifers in yr 2 to 4 were fed ad libitum meadow hay while grazing dormant pasture. Prior to breeding, heifers were transrectally ultrasounded to determine AFC and classified as high (>/=26 follicles; HIGH) moderate (16-25; MOD) or low ( |
