The effects of creep feed duration in a drylot system on cow performance as well as calf performance, ruminal fermentation characteristics, and carcass traits

The objectives were to determine effects of creep feed duration in a drylot system on cow performance as well as calf performance, ex vivo ruminal fermentation characteristics, and carcass traits. Spring-calving, SimAngus cows (5 ± 2 yr; n = 72) were stratified by calf age (83 ± 14 d), sex, and body weight (BW; 130 ± 17 kg) and allotted to 12 pens with six cow-calf pairs per pen. Pens were randomly assigned to 1 of 2 treatments: calves fed commercial, pelleted creep feed (14% CP) for 105 d (105dCF) or final 21 d (21dCF) prior to weaning. Cow-calf pairs were housed in concrete drylots with open-front buildings, and cows were limit fed at maintenance. On d 76 and 105 rumen fluid was collected from a subset of 16 steers to determine rumen fermentation characteristics utilizing different substrates. Calves were weaned on d 105, trucked 263 km to a feedlot, fed for 194 d, and slaughtered on d 300. Reproduction data were analyzed using GLIMMIX and all other response variables were analyzed using the MIXED procedure of SAS 9.4. There were no differences (P ≥ 0.18) in cow BW, BCS, milk production, milk composition, or reproductive data. The 105dCF calves had greater (P ≤ 0.01) ADG and BW for the pre-weaning period. The 105dCF had greater (P ≤ 0.01) IVDMD and there was a treatment × substrate interaction (P = 0.02) for total VFA on d 76. Within the 105dCF, there were no differences between substrates, however, within 21dCF the creep substrate yielded more total VFA. At weaning, the 105dCF calves had greater (P ≤ 0.01) ultrasound longissimus muscle area, rib fat, and rump fat compared with 21dCF. On d 105, the 21dCF calves tended (P = 0.06) to have greater ex vivo IVDMD; however, there were no treatment differences (P = 0.57) for total VFA. The 21dCF calves had greater (P = 0.01) ADG and tended to have greater (P = 0.08) G:F during the receiving period. The 105dCF calves had greater (P ≤ 0.01) BW at the end of the receiving period. There were no differences (P ≥ 0.22) in ADG, DMI, or G:F from d 238- 298. There were no differences (P ≥ 0.12) in final BW or carcass traits. The 105dCF calves had greater (P ≤ 0.01) creep feed costs and weaned calf value. However, there were no differences (P = 0.74) in final carcass value. In conclusion, creep feed duration did not impact cow performance. The 105dCF calves had increased ADG and BW for the pre-weaning period. Creep feeding improved ruminal fermentation ex vivo, but even a short-term creep feeding duration of 21 d appears to be adequate in preparing the rumen bacterial community. The 21dCF had improved gain during the receiving and finishing phases and compensated for previous restriction, ultimately resulting in similar final carcass characteristics as well as final carcass value.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Animal Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Pugh, Lindsey Marie

Contributors dc:contributor

• Shike , Daniel W
• McCann, Joshua C
• Meteer, William T

• Creep Feeding
• Drylot
• Confinement
• Beef Cow-calf
• Ex Vivo Rumen Fermentation
• Compensatory Gain

Statement dc:rights

• Copyright 2023 Lindsey Pugh

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/120153

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F120153