|AKINS, MATTHEW - UNIVERSITY OF WISCONSIN|
|ESSER, NANCY - UNIVERSITY OF WISCONSIN|
|GELSINGER, SONIA - UNIVERSITY OF WISCONSIN|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/14/2018
Publication Date: 6/25/2018
Citation: Coblentz, W.K., Akins, M.S., Esser, N.M., Ogden, R.K., Gelsinger, S.L. 2018. Effects of overstocking at the feedbunk on the growth performance of replacement holstein dairy heifers. Journal of Dairy Science. J. Dairy Sci. 101 (suppl. 2):260.
Technical Abstract: Various forms of overcrowding are common in heifer-rearing operations. Our objectives were to evaluate the effects of overstocking at the feedbunk (100, 133, 160, or 200% of capacity) on the voluntary intake, growth performance, feedbunk-sorting behaviors, displacements from the feedbunk, and hygiene of 128 gravid Holstein heifers (475 ± 55.3 kg) consuming an alfalfa haylage/corn silage diet diluted with processed wheat straw at an inclusion rate of 25.2% (DM basis). Heifers were blocked by weight, and subsequently assigned to 1 of 16 identical research pens (4 pens/weight block). A TMR was distributed at 1000 h daily for 91 d via a drive-through feed alley with heifers allowed access to the feedbunk through head-locking feeding gates. Overstocking was created by blocking access to 0, 2, 3, or 4 feeding gates with plywood partitions. Nutrient intakes were not affected by stocking rate at the feedbunk (P = 0.122). Overall, the effects of feedbunk stocking rate on growth performance were minor, with only trends for linear increases in total weight gain (P = 0.086) and BCS (P = 0.066) observed. Collectively, overstocked rates also exhibited a trend (P = 0.078) for a better feed:gain ratio than pens stocked at 100% of feedbunk capacity (10.3 vs. 11.0 kg/kg). Heifers sorted against large (> 19-mm) particles and NDF, but exhibited preference for short (> 1.18-mm, and < 8-mm) and fine (< 1.18-mm) feed particles, as well as CP over time. However, these responses were not affected by feedbunk-stocking rate (P = 0.205) or the interaction of stocking rate and daily sampling times (P = 0.364). During the first hour after daily feed distribution, heifer displacements from the feedbunk were greater (P = 0.007) for overstocked pens, and increased linearly (P = 0.030) with stocking rate for most evaluation periods (weeks 1, 2, 4, 6, 8, 10, and 12 of the trial). Displacements exceeded 70/h in pens stocked at 200% of capacity during weeks 1, 2, and 12. Heifer hygiene of legs and flanks was not affected (P = 0.136) by competition at the feedbunk. While overstocking at the feedbunk did not affect heifer performance, it should not be practiced blindly without attention to other critical components of animal welfare.