Files in this item

FilesDescriptionFormat

application/pdf

application/pdfAdcock_Justin.pdf (339kB)
(no description provided)PDF

Description

Title:Factors influencing cow performance and intake
Author(s):Adcock, Justin W.
Advisor(s):Faulkner, Dan B.
Department / Program:Animal Sciences
Discipline:Animal Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:M.S.
Genre:Thesis
Subject(s):cow
efficiency
early weaning
intake
Abstract:ABSTRACT FACTORS INFLUENCING COW PERFORMANCE AND INTAKE Two studies were conducted to determine how weaning system, residual feed intake (RFI), and residual average daily gain (RADG) affect cow performance and intake. In Study 1, a two-year study was conducted using Angus and Simmental X Angus heifers (n=114) to evaluate how weaning system (early weaning (EW) vs. normal weaning (NW)) affects cow-calf performance and intake. All cows with male calves were early weaned at 130 d while cows with female calves were normal weaned at 200 d. These animals were then evaluated for individual intake at 60 d, 120 d, 180 d, and 240 d postpartum. Weigh-suckle-weigh (WSW) was used to determine milk production for the lactating periods. BW, Hip height, body condition score (BCS, 1-9 scale), and backfat via ultrasound were measured. No differences (P > 0.05) were noted in the 60 and 120 d postpartum cow measurements, but calf BW did differ (P < 0.05) with male calves being heaver. At 180 d postpartum cows with their offspring early-weaned had increased (P < 0.05) BW (18.7 kg), BCS (0.29) and decreased DMI (1.23 kg). At 240 d postpartum cows that had been early-weaned had an increased (P < 0.05) BW (30.5 kg), BCS (0.31), and BF (0.22 cm). There were no differences (P > 0.05) in DMI or overall pregnancy rate. Early weaning can improve cow condition and decrease intake, allowing for increased stocking rates. In Study 2, a two-year study was conducted using Angus and Simmental X Angus heifers (n=114) to determine their residual feed intake (RFI) and residual average daily gain (RADG) as yearlings using the GrowSafe® system. These animals were then evaluated for individual intake at 60 d postpartum (lactating period) and 240 d postpartum (dry period). The same measurements were taken as in Study 1. For the lactating period, correlations were: heifer DMI and cow DMI (0.35), heifer RFI and cow DMI (0.20), heifer RFI and cow BW (-0.08), iii heifer RFI and cow hip height (0.02), heifer RFI and milk production (-0.09), heifer RADG and cow DMI (-0.06), heifer RADG and cow BW (0.21), heifer RADG and cow hip height (0.25), and heifer RADG and milk production (0.03). For the dry period correlations were: heifer DMI and cow DMI (0.06), heifer RFI and cow DMI (0.29), heifer RFI and cow BW (0.00), heifer RFI and cow hip height (-0.09), heifer RADG and cow DMI (-0.10), heifer RADG and cow BW (0.23), and heifer RADG and cow hip height (0.31). Heifer RFI is correlated with cow intake and thus can be used to help predict intake and efficiency without effecting performance.
Issue Date:2011-08-25
URI:http://hdl.handle.net/2142/26072
Rights Information:Copyright 2011 Justin W. Adcock
Date Available in IDEALS:2011-08-25
Date Deposited:2011-08


This item appears in the following Collection(s)

Item Statistics