Effect of weaning date (normal vs. late) on performance of young and mature beef cows and their progeny in a fall calving system in the Southern Great Plains1

Abstract

Data from 158 predominantly Angus fall-calving beef cows were used in 4 consecutive years to determine the effects of weaning date and cow age class on cow and calf performance. Treatments were arranged in a 2 x 2 factorial with 2 weaning dates and 2 age classes (young cows <or=3 yr and mature cows >or=4 yr). Weaning dates were 1) normal weaning in mid-April at 210 d of age (NW) and 2) late weaning in mid-July at 300 d of age (LW). Mature cows were heavier (P < 0.01) than young cows throughout the trial, although BCS was similar (P >or= 0.10) among cow age classes. Cow BW (P = 0.58) and BCS (P = 0.40) were similar among weaning treatments at NW; however, at the beginning of the calving season, NW cows were heavier (585 vs. 562 kg; P = 0.02) and had greater BCS (6.57 vs. 5.95; P < 0.0001) than LW cows. Postpartum BW and BCS losses were greater (P < 0.0001) for NW cows, resulting in similar BW (P = 0.56) and BCS (P = 0.07) at the beginning of the breeding season and until April. Progeny of NW cows were 2.4 kg heavier (P < 0.01) at birth and grew faster before the April weaning date, resulting in increased BW (8 kg; P < 0.05) at the time of normal weaning. This increase in BW gain may be partially explained by the increased milk production of NW cows (0.59 kg/d as measured in February; P < 0.05). Although NW calves had increased BW in April, LW calves were heavier in July because of increased ADG during the weaning interval (1.13 vs. 0.8 kg; P < 0.0001). A cow age class x weaning date interaction (P = 0.007) was detected for pregnancy rate. Pregnancy rates were greater (P < 0.10) for LW-mature cows (96.7%) and NW-young cows (98.4%) than for LW-young cows (89.3%). However, pregnancy rate of NW-mature cows (90.2%) did not differ (P = 0.12) from that of LW-mature or LW-young cows, but was less than that of NW-young cows. These findings indicate that producers may benefit from matching weaning date to cow age class. It appears more advantageous to delay weaning of calves born to dams 4 yr or older while maintaining NW for dams 3 yr or younger at the time of calving. Late weaning had no detrimental effects on the performance of mature cows.

Maintenance energy requirements and forage intake of purebred vs. crossbred beef cows1

“…Likewise, Choy et al (2002) found that BCS increased up to 6 yr of age. The results in the current study are similar to Hudson et al (2010) who found no difference in BCS between young cows (≤3 yr) and mature cows (≥4 yr). When Banta et al (2008) evaluated 2-yr-old, 3-yr-old, and mature cows, there was a difference between age classes in initial BCS where 2-yr-olds had the greatest BCS, mature cows had the lowest BCS, and 3-yr-old cows were intermediate.…”

“…When Banta et al (2008) evaluated 2-yr-old, 3-yr-old, and mature cows, there was a difference between age classes in initial BCS where 2-yr-olds had the greatest BCS, mature cows had the lowest BCS, and 3-yr-old cows were intermediate. However, in both previously mentioned studies, younger cows lost a greater amount of BCS throughout the production cycle resulting in no differences in prebreeding BCS between age groups ( Banta et al, 2008 ; Hudson et al, 2010 ). This suggests that while BCS may not differ greatly between age groups, mature cattle may be capable of maintaining condition during physiologically stressful periods (i.e., early lactation, weaning, etc.).…”

Effect of muscle type, sire breed, and time of weaning on fatty acid composition of finishing steers1

“…Steers were weaned on 1 of 2 dates: normal weaned in mid-April at approximately 210 d of age (NW) or late weaned in mid-July at approximately 300 d of age (LW). Before and at weaning, calves were managed according to procedures outlined by Hudson et al (2010a). Postweaning, all steers were managed according to Hudson et al (2010b).…”

Evaluation of two-stage weaning and trace mineral injection on receiving cattle growth performance and behavior

“…Most beef operations wean by abruptly separating the cow and calf, usually at a much younger age than in a natural or self-weaning situation (Hudson et al, 2010). The results of abrupt weaning are well documented and consistent, as cows and calves spend more time walking and vocalizing and less time resting or eating (Veissier and Le Neindre, 1989).…”