Testing preference for corn milling coproducts by lactating Jersey cows

Manipulations at the intersection of nutrition, behavior, and management may be an important way to apply novel feeding strategies that take advantage of affordable feeds and a cow's natural behavior to increase feed intake. The grain fuel sector continues to modify methods for how corn ethanol is produced. This has resulted in different feed coproducts that can be utilized by the dairy industry. The objective of this study was to determine how preferences of various corn milling coproducts differ and also compare them with corn grain. Eight lactating Jersey cows (169 ± 4 DIM, 29.7 ± 4.55 kg/d milk yield, 21.3 ± 2.78 kg/d DMI; mean ± SD) were utilized. The treatments tested included dried corn distillers grains with solubles (DDGS) in meal form, corn fermented protein (CFP) product in meal form, pelleted corn distillers grains (PEDG), and finely ground corn grain (CRNG). During the experiment, cows consumed a corn-silage-based TMR with 59.8% DM, 17.3% CP, 25.6% starch, and 26.0% NDF. Preference testing was always provided before providing the dairy allotment of TMR. Cows were offered 0.45 kg in each treatment, which was randomly arranged for each cow within their feed bunk. Cows were allowed access to all treatments for 1 h or until the single most preferred feed was fully consumed. Feeds were offered for 9 d with all treatments presented the first 4 d. The most preferred feed was then removed, and the remaining 3 feeds were offered for 3 d. The process was repeated for the last 2 d. Feed preference was ranked from 1 to 4 with 1 being the most preferred and 4 the least. The rankings of each treatment for each cow were summed and averaged. The PEDG was chosen as the most preferred feed (1.00 ± 0.25; mean ± SD) followed by CRNG (2.14 ± 0.38), DDGS (2.50 ± 0.58), and CFP (4.00 ± 0.00). The results were then examined using the Plackett-Luce model to determine the probability a treatment would be chosen first based on the current dataset. The probability of PEDG being selected first was observed to be 98.8% ± 1.60%, whereas the probabilities of CRNG, DDGS, and CFP being selected first were 0.93% ± 0.69%, 0.21% ± 0.73%, and 0.07% ± 0.86%, respectively. Results of this study demonstrate preference is increased over corn when DDGS are pelleted.