Effects of dietary starch and fatty acid supplementation on milk production and metabolic responses during the immediate postpartum period in dairy cows
Year: 2025
Type: article
Abstract: This study aimed to investigate the interaction between dietary starch and fatty acid (FA) supplementation on production responses in multiparous Holstein cows. Sixty multiparous Holstein cows were used in a randomized complete block design and assigned to one of 4 treatments in a 2 × 2 factorial arrangement. The following treatment diets were fed from 1 to 23 d postpartum (fresh period; FR): (1) a diet containing 22% DM starch and no supplemental FA (LS); (2) a diet containing 28% DM starch and no supplemental FA (HS); (3) a diet containing 22% DM starch and a calcium salt containing 70% C16:0 and 20% cis-9 C18:1 (LS+FA); and (4) a diet containing 28% DM starch and a calcium salt containing 70% C16:0 and 20% cis-9 C18:1 (HS+FA). The starch concentration of the treatment diets was altered by partially replacing ground corn with soyhulls and soybean meal. The FA supplement was added at 2.6% of diet DM to deliver ∼2.0% of FA and replaced soyhulls in the FA-supplemented diets. During the carryover period (CO; 24-44 d postpartum), all cows were offered a common diet (27.8% starch and 3.05% FA of DM) to evaluate the carryover effects of the treatment diets. During FR, dietary starch and FA supplementation interacted with time to affect DMI, plasma BHB, and tended to interact to affect ECM yield and milk lactose content. The starch × FA interaction affected the yields of milk, milk fat, milk lactose, 3.5% FCM, ECM, and tended to affect milk protein yield and FCM/DMI. Based on pairwise comparisons among treatment combinations, HS increased milk and lactose yields compared with the other treatments. The HS and LS+FA diets increased milk fat yield compared with LS, and HS increased 3.5% FCM and ECM yields compared with LS, whereas LS+FA tended to increase 3.5% FCM yield compared with LS. Overall, increasing dietary starch increased milk and lactose yields, tended to increase DMI, and reduced plasma BHB concentration. Supplemental FA increased FCM/DMI and plasma nonesterified fatty acid and BHB concentrations; reduced DMI, BW, and plasma insulin and glucose concentrations; and tended to increase ECM/DMI and BCS loss. During the CO, increasing dietary starch during FR increased milk lactose yield and tended to increase milk yield and milk lactose content, whereas FA supplementation reduced BW, tended to reduce milk lactose content, and tended to increase BCS loss. In conclusion, the effect of FA supplementation on milk production of early-lactation cows depended on dietary starch level. Additionally, feeding high-starch diets during FR improved milk yield, with effects that were partially carried over into established lactation, indicating that early FP diet can influence performance in the weeks thereafter.
Source: Journal of Dairy Science
Authors: J.E. Parales-Girón, A.C. Benoit, A.L. Lock
Institution: Michigan State University
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,500
OpenAlex ID: W4417465917