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University of Nebraska - Lincoln
Department of Animal Science: Dissertations, Theses, and Student Research
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Attainment And Maintenance Of Pubertal Cyclicity May Predict High A4 Cows With Reduced Fertility, Sarah Nafziger
Attainment And Maintenance Of Pubertal Cyclicity May Predict High A4 Cows With Reduced Fertility, Sarah Nafziger
Department of Animal Science: Dissertations, Theses, and Student Research
Puberty attainment was investigated in heifers. Blood samples were collected from weaning until breeding during 6 years from heifers born in 2012-2017. Plasma progesterone concentrations ≥ 1 ng/ml were used to indicate cyclicity, and heifers were categorized into one of four puberty groups using SAS: 1) Early heifers reached puberty before March 12 and cycled continuously during the sampling period, 2) Typical heifers reached puberty on or after March 12 and cycled continuously, 3) Start-Stop heifers had at least one occurrence of progesterone ≥ 1 ng/ml but discontinued cycling during the sampling period, and 4) Non-Cycling heifers had no occurrence …