|Akins, Matthew - University Of Wisconsin|
|Esser, Nancy - University Of Wisconsin|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/13/2016
Publication Date: 6/15/2016
Citation: Coblentz, W.K., Akins, M.S., Esser, N.M. 2016. Heifer stocking density and performance. Meeting Proceedings. Pages 44-50.
Technical Abstract: Although replacement dairy heifers are frequently offered forage-based diets, this management practice may still result in over-conditioning, especially if significant proportions of corn silage are included in the diet. Generally, two approaches are recommended to address this problem: i) precision or limit feeding; and ii) dietary dilution with low-energy forages. However, both strategies have advantages and disadvantages, and the effectiveness of both management approaches can be affected by over-crowding. The use of low-energy forages (dilution) acts to limit weight gains by two mechanisms: i) reducing the energy density of the diet; and ii) limiting voluntary intake via gut-fill, where heifers generally are limited to about 1% of their bodyweight for daily NDF intake. Although heifers will exhibit different sorting behaviors with various diluting agents, these behaviors can not be linked directly to growth performance through our studies. The variability of daily weight gains within-pen may trend greater with more sortable diets, but (to date) these observations have not been statistically significant. Feeding management in these trials was designed to maximize ad-libitum intake, but with minimal orts, thereby ensuring nearly 100% consumption of all feed components within a 24-hour period. This approach is consistent with current recommendations for including straw in TMR diets, and may have restricted within-pen variability in growth performance. Over-stocking within the pen, such that heifers did not always have an available stall, resulted in increased (poorer) hygiene scores, as well as a greater percentage of heifers lying in alleys or inactively standing during night hours. Furthermore, within-pen variability of hygiene scores increased sharply with over-stocking, but the relative magnitude of hygiene scores suggests that heifers remained relatively clean, despite over-stocking.