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Title:Fetal programming effects of early weaning on subsequent calf performance
Author(s):Oattes, Jack Lloyd
Advisor(s):Shike, Daniel W.
Contributor(s):McCann, Joshua C.; Parrett, Douglas F.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):early weaning
fetal programming
Abstract:Mature Simmental × Angus cows (n = 147; BW = 590 ± 72 kg) were used to evaluate the effects of early weaning on subsequent calf growth performance and carcass characteristics. Cows were assigned to 1 of 2 treatments based on their previous calf’s weaning age: 1) early wean (EW) or 2) conventional wean (CW). The EW treatment had a steer calf weaned at 88 ± 6 days of age where as the CW treatment had a heifer calf that was weaned at approximately 185 ± 6 days of age. Cow body weight (BW) and body condition (BCS) were monitored at 10 time points during the experiment. All cows were managed as a common group from the onset of the experiment at breeding until final pregnancy check of their next production cycle 462 days later. All calves in the experiment were managed as one group and weaned at a single time point, then feedlot performance and carcass characteristics were evaluated. Initial cow BW was different (P < 0.05), as such it was included as a covariate. There was a treatment × date interaction (P < 0.01) for cow BW and cow BCS. Cow BW was consistently greater for the EW treatment at all time points throughout the experiment (P < 0.01). Cow BCS were not different at the onset of the experiment (P = 0.20), although after breeding and throughout lactation, body condition scores diverged between treatments and the EW treatment consistently had greater (P < 0.01) BCS than the CW treatment throughout the entire subsequent lactation. Gestation length was not different (P = 0.21) between treatments, yet calf birth BW was greater (P = 0.05) for the EW treatment. Both AI pregnancy percentage and overall pregnancy percentage were not different between treatments (P ≥ 0.61). Despite the greater birth BW for the EW treatment and no difference (P = 0.25) in milk production, weaning BW was not different (P = 0.50) between treatments. Feedlot performance measures were not different between treatments including: feedlot arrival weight (P = 0.13); final body weight (P = 0.66); average daily gain (P = 0.84); dry matter intake (P = 0.84); and gain to feed (P = 0.93). Final carcass characteristics were not different between treatments including: dressing percentage (P = 0.33); hot carcass weight (P = 0.96); ribeye area (P = 0.94); 12th rib fat thickness (P = 0.73); kidney, pelvic, heart fat percentage (P = 0.08); USDA yield grade (P = 0.80); and marbling score (P = 0.70). Thus, early weaning resulted in improved BW and BCS of cows as well as increased birth BW although that did not transpire into differences in postnatal growth performance or carcass traits of calves.
Issue Date:2019-04-26
Type:Text
URI:http://hdl.handle.net/2142/105093
Rights Information:Copyright 2019 Jack Oattes
Date Available in IDEALS:2019-08-23
Date Deposited:2019-05


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