Factors influencing cow performance and intake

cow;efficiency;early weaning;intake

Adcock, Justin W. ; Faulkner ; Dan B.

关键词: cow;    efficiency;    early weaning;    intake;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/26072/Adcock_Justin.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

ABSTRACTFACTORS INFLUENCING COW PERFORMANCE AND INTAKETwo 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, atwo-year study was conducted using Angus and Simmental X Angus heifers (n=114) to evaluatehow weaning system (early weaning (EW) vs. normal weaning (NW)) affects cow-calfperformance and intake. All cows with male calves were early weaned at 130 d while cows withfemale calves were normal weaned at 200 d. These animals were then evaluated for individualintake at 60 d, 120 d, 180 d, and 240 d postpartum. Weigh-suckle-weigh (WSW) was used todetermine 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) werenoted in the 60 and 120 d postpartum cow measurements, but calf BW did differ (P < 0.05) withmale calves being heaver. At 180 d postpartum cows with their offspring early-weaned hadincreased (P < 0.05) BW (18.7 kg), BCS (0.29) and decreased DMI (1.23 kg). At 240 dpostpartum 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 pregnancyrate. Early weaning can improve cow condition and decrease intake, allowing for increasedstocking rates. In Study 2, a two-year study was conducted using Angus and Simmental XAngus heifers (n=114) to determine their residual feed intake (RFI) and residual average dailygain (RADG) as yearlings using the GrowSafe® system. These animals were then evaluated forindividual intake at 60 d postpartum (lactating period) and 240 d postpartum (dry period). Thesame measurements were taken as in Study 1. For the lactating period, correlations were: heiferDMI and cow DMI (0.35), heifer RFI and cow DMI (0.20), heifer RFI and cow BW (-0.08),iiiheifer RFI and cow hip height (0.02), heifer RFI and milk production (-0.09), heifer RADG andcow 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 DMIand cow DMI (0.06), heifer RFI and cow DMI (0.29), heifer RFI and cow BW (0.00), heifer RFIand 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 intakeand thus can be used to help predict intake and efficiency without effecting performance.