|LOYD, ANDREA - Texas Agrilife Research|
|VANN, RHONDA - Mississippi State University|
|BANTA, JASON - Texas Agrilife Extension|
|WELSH JR, THOMAS - Texas Agrilife Research|
|Carroll, Jeffery - Jeff Carroll|
|RANDEL, RONALD - Texas Agrilife Research|
Submitted to: Extension Service Bulletins
Publication Type: Other
Publication Acceptance Date: 8/20/2011
Publication Date: 10/1/2011
Citation: Loyd, A.N., Vann, R.C., Banta, J.P., Welsh Jr, T.H., Carroll, J.A., Randel, R.D. 2011. Post-weaning feeding behavior of newly weaned heifer calves. Mississippi State University, Department of Animal and Dairy Sciences Departmental Report. p. 19-25.
Interpretive Summary: Although cattle may be exposed to a variety of stressors throughout their lifetimes, a particularly stressful period for calves often occurs in conjunction with weaning. Understanding the feeding behavior of weaned calves is crucial to the development of strategies to successfully manage these calves. Therefore, scientists from the Livestock Issues Research Unit, Texas AgriLife Research at Overton and College Station, Texas AgriLife Extension, and Mississippi State University conducted a collaborative study to characterize the post-weaning feeding behavior and subsequent growth performance of abrupt-weaned heifer calves using GrowSafe technology. Results from this study revealed that considerable variation exists in post-weaning feeding behavior of Brahman x British heifer calves not previously exposed to grain-feeding in bunks. Some of this variation can be attributed to breedtype and calf temperament, especially during the initial days when calves are adjusting to the bunks and diet. Additionally, it appears that more temperamental heifers and heifers with a greater proportion of Brahman influence take longer to acclimate to consuming feed from GrowSafe bunks. However, the impacts of temperament and Brahman influence on feeding behaviors were eliminated by 26 days post-weaning. These data highlight important considerations when utilizing newly weaned calves in feeding trials that utilize GrowSafe bunks or similar feeding systems and when managing abruptly weaned calves from pasture environments into feedlot environments. Results from this study will be of particular interest to beef producers, feedlot managers, and rumen nutritionists evaluting post-weaning performance of beef cattle.
Technical Abstract: Stress experienced by calves at weaning often culminates in poor post-weaning feed intake (FI) and growth performance. The objective of this study was to characterize the feeding behavior of calves post-weaning. Brahman x British heifers (n = 48) born in spring 2010 at the Brown Loam Branch Experiment Station in Raymond, MS, were abruptly weaned from their dams at 200 days of age. Heifers were penned in one of two dry-lots and received ad libitum access to a high roughage diet offered in GrowSafe bunks. Feeding behavior was monitored for 24-26 days post-weaning and body weight (BW) was evaluated weekly beginning at weaning. Data were analyzed using mixed models with day as a repeated measure when applicable. The number and duration of daily meal events, the duration of daily head down time, and daily FI increased with time post-weaning (P < 0.0001). Body weight was similar for all time-points (P = 0.32), however, there was great variation in the number of days it took heifers to first approach the feed bunks, eat feed for the first time, eat feed consistently for at least 5 days, and consume enough feed to meet estimated net energy for maintenence (NEm) requirements. To account for this variation, pen, temperament score, and the proportion of Brahman influence were included in the statistical model. Brahman-influenced heifers were slower (P < 0.03) to attend the bunks, begin consuming feed, consistently consume feed, and consume enough feed to meet NEm requirements. However, there was no effect (P > 0.10) of breedtype on feeding behavior or FI over the course of the entire feeding period. These data suggest there is considerable variation in post-weaning feeding behavior, of which some can be attributed to breedtype. These data also highlight important considerations when utilizing newly weaned calves in feeding trials, especially those using GrowSafe bunks or similar feeding systems, and when managing abruptly weaned calves from pasture environments into feedlot environments.