PS4-11. Effects of Ad Libitum Creep Feed Access on Calf Behavior Following Feeding of Cow Total Mixed Ration in a Confinement Cow-calf System

The objective was to evaluate the effects of providing ad libitum creep feed in a confinement system on calf behavior following feeding of cow total mixed ration. Spring-calving, Simmental × Angus cows (4.7 ± 1.7 yr; n = 36) were allotted to six partially covered, drylot pens with six cow-calf pairs per pen. Cows were limit fed a total mixed ration (TMR) at maintenance. Cow-calf pairs were stratified by cow sire and initial cow body weight (BW; 647 ± 94 kg) and calf BW (176 ± 18 kg; 119 ± 11 days of age). Three pens were randomly assigned to each treatment: ad libitum creep feed access for 21 days (CF), or no creep feed access (NCF). During a 3-week creep feeding period, a single observer recorded behavior observations from the alleyway in front of the pens three times per week. Data were averaged across all nine observation days for analysis. Each observation day began at time of feeding, and calf behavior was evaluated every 10 min for 70 min. Calf behaviors recorded included lying or standing and their location: cow TMR bunk, cow TMR feeding area, bedded area, or open lot area. Data were analyzed using the GLIMMIX procedure with a beta distribution in SAS 9.4. There was no treatment × time interaction (P = 0.98) for percentage of calves lying or standing. However, there was a greater (P = 0.01) percentage of CF calves that were lying compared with NCF calves. There was a treatment × time interaction (P = 0.01) for calves at the cow TMR bunk. Less CF calves were located at the cow TMR bunk than NCF calves at 0, 20, 30, 40, 50, 60, and 70 minutes after feeding. There was a treatment × time interaction (P = 0.01) for calves in the cow TMR feeding area. From 10 to 70 minutes after feeding, there were fewer CF calves in the cow TMR feeding area than NCF calves. There was no treatment × time interaction (P = 0.67) for percentage of calves in the bedded area. However, there was a greater (P = 0.01) percentage of CF calves that were in the bedded area compared with NCF. There was a treatment × time interaction (P = 0.01) for calves in the open lot area. At 0 and 70 minutes after feeding, there was a greater percentage of CF calves in the open lot area, and at 10 minutes after feeding there tended to be more CF calves in the open lot area. Offering ad libitum creep feed reduced calf proximity to the cow TMR bunk after feeding, suggesting creep-fed calves were less interested in competing for additional feed resources.