kg/d, respectively). Plasma concentrations of Lys prepartum (69.8 ± 1.8 µM) increased for cows in PRE-L compared with those in PRE-C (62.5 ± 1.3 µM). In conclusion, RPL consumed prepartum tended to increase postpartum DMI and increased energy-corrected milk and milk component yields. This indicates that prepartum supply of intestinally available Lys is pertinent to postpartum performance. However, postpartum supply of intestinally available Lys had no effect on cows' performance.

Calcium salts of fatty acids (CSFAs) frequently are fed to ruminants, but their fate in the equine digestive system is unknown. The purpose of this study was to compare Enertia s/f, a proprietary CSFAs, and soybean (SB) oil with respect to impact on apparent total tract nutrient digestion and cecal fermentation parameters in horses. Eight cecally cannulated Quarter Horses were used in a crossover design in which horses consumed a diet for 32 d consisting of 1.5% body weight (BW) (as-fed) smooth bromegrass hay and 0.5% BW (as-fed) pelleted concentrate containing 4.9% CSFAs or 4.1% SB oil. Fecal samples were collected every 4 h from day 30 to 32 of each period and analyzed for apparent total tract digestibilities of dry matter (DM), neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), crude fat (CF), and gross energy (GE) using acid detergent insoluble ash as an internal marker. Cecal digesta was obtained at 0, 2, 4, 6, 8, 10, and 12 h following the morning meal on day 29 of each period and analyzed for pH and concentrations of volatile fatty acid (VFA) and long-chain fatty acids (LCFAs). Serum was collected on day 33 of each period following a 16-h fast and analyzed for triglycerides and cholesterol. Apparent total tract digestibilities of DM, NDF, ADF, CP, CF, and GE were unaffected by lipid source (P > 0.10). Serum triglycerides tended to be greater in horses consuming CSFAs compared to SB (P = 0.10); however, serum cholesterol was not different (P = 0.45). In horses consuming SB, cecal pH decreased below baseline (hour 0) at hours 2, 4, and 6 (P < 0.01), whereas cecal pH in horses consuming CSFAs was below baseline at hours 4 and 6 (P < 0.01). There were no treatment or time effects on cecal pH (P > 0.10). Cecal concentrations of total VFAs were greater in horses consuming SB compared to CSFAs at hour 2 (P = 0.01). Cecal concentrations of acetate, propionate, acetate:propionate (A:P), and butyrate were affected by time (P < 0.01). Propionate was less at hour 2 in horses fed CSFAs compared to horses fed SB (P = 0.04). A treatment × time interaction was detected for total cecal LCFAs concentration (P < 0.01); LCFAs concentration was greater at hour 2 for horses consuming CSFAs compared to horses fed SB (P = 0.02). SB oil and CSFAs have similar effects on the digestion of DM, NDF, ADF, GE, CF, and CP.

No abstract

Feeding rumen-protected methionine as an indispensable amino acid source has been shown to improve reproductive performance in dairy cows, but the effect of feeding rumen-protected lysine (RPL) during the peripartum period on reproductive performance is not well explored. Therefore, we aimed to determine the effects of feeding RPL (AjiPro-L Generation 3, Ajinomoto Heartland Inc.) prepartum, postpartum, or both on follicular dynamics, uterine health, and mRNA gene expression of the endometrium. Seventy-five multiparous Holstein cows were assigned to 1 of 2 dietary treatments with or without RPL in a randomized, complete block design. A 2 × 2 factorial arrangement of treatments was used. Prepartum (-28 d to calving), animals were fed a diet (68% of dietary DM from forage) with RPL [PRE-L; 0.54% RPL of dietary dry matter intake] or without RPL (PRE-C). After calving, half of the cows from each prepartum treatment group were assigned to a diet (56% forage) with RPL (PRE-L POST-L; PRE-C POST-L; 0.40% RPL of dietary dry matter intake) or without RPL (PRE-C POST-C; PRE-L POST-C) until 28 d in milk (DIM). Vaginal discharge was detected with a Metricheck device (Simcro) to detect metritis, and at 28 DIM polymorphonuclear leukocytes were evaluated as a percentage of the epithelial cells using a cytology brush (Andwin Scientific) and an endometrial tissue biopsy was collected for mRNA expression and histology. The first postpartum follicular growth cycle was monitored