32 Nutritional management of forage-based cow-calf operations

Abstract The beef cattle industry in the Southeastern United States relies primarily on forages that not always meet the cowherd nutritional requirements, resulting in reduced performance if supplemental nutrients are not provided. Although precalving nutrition modulates postnatal offspring performance, most studies did not utilize Bos indicus-influenced cows consuming low-quality, warm-season forages. Hence, 3 studies evaluated the impact of different supplementation strategies during gestation on subsequent cow and calf performance.Study 1focused on timing of dried distillers grains (DDG) supplementation during late-gestation. Treatments initiated 84 d before calving and consisted of no supplementation, 1 kg/d of DDG from d 0 to 84, or 2 kg/d of DDG from d 0 to 42. Timing of prepartum DDG supplementation did not impact cow reproduction, but calf pre-weaning growth was enhanced only when cows received longer vs. shorter or no periods of prepartum supplementation. Study 2evaluated the use of prepartum supplementation of sugarcane molasses/urea added or not with DL-methionine hydroxyl analog. At 56 d before calving, Brangus heifers received no supplementation or molasses/urea (7.2 kg DM/wk) with or without methionine (105 g/wk; Alimet, Novus) until calving. Sugarcane molasses/urea supplementation improved cow BCS at calving and calf postnatal growth compared to no supplementation. However, supplemental methionine did not further enhance cow and calf growth performance. Study 3 compared winter vs. annual supplementation of sugarcane molasses/urea or range cubes. Starting on d 0 (pregnancy diagnosis; May), Brangus cows were assigned to receive molasses/urea supplementation during winter only (calving until end of breeding season) or year-round supplementation of molasses/urea or range cubes. Treatments had similar annual supplement DM amount (272 kg/yr). Year-round supplementation of molasses/urea and range cubes enhanced cow BCS at calving but did not impact pregnancy rate of cows and calf weaning weights than winter molasses/urea supplementation.