PSVI-21 - Effects of calcium salts of soybean oil supplementation to Nellore heifers during second and third trimesters of gestation and offspring sex on milk production and performance of the offspring

Abstract: The study aimed to evaluate the effects of supplementing calcium salts of soybean oil to Nellore heifers during the second and third trimesters of gestation and offspring sex on cow productivity and their male and female offspring growth. Forty-eight pregnant Nellore heifers (body weight [BW] = 387 ± 38.4 kg) were assigned to this experiment at day 123 ± 13 of gestation. All heifers were conceived during the same fixed-time artificial insemination protocol at 14 and 24 months of age. Heifers were randomly used in a completely randomized block design with a 2 × 2 factorial treatment arrangement, consisting of supplementing or not (CON) calcium salts of soybean oil (CSSO; 3 g/kg of BW) and the sex of the offspring (male or female), totaling four treatments and twelve reps per treatment. Throughout the experimental period, heifers were maintained in a pasture composed of Brachiaria brizantha cv.Marandu. After birth, all animals remained under the same pasture conditions and received the same supplementation until weaning. Data were analyzed using the MIXED procedure of SAS and heifer as the experimental unit. Treatment × offspring sex interaction was not detected (P > 0.36) for any of the variables evaluated. Calves born from heifers supplemented with CCSO were 2 kg heavier (P = 0.03) at birth and 5 kg heavier (P = 0.03) at 120 days of age compared with calves born from CON heifers. At weaning (210 days), no dietary treatment effects were observed (P = 0.17) in offspring BW. Male offspring were 3.5 kg, 9 kg, and 12 kg heavier (P ≤ 0.01) at birth, day 120, and at weaning, respectively, compared with female offspring. Throughout the experiment, male offspring gained 0.040 kg more daily (P = 0.01) than female offspring. The female offspring had 0.1 thicker subcutaneous fat per 100kg of body weight (P=0.02) than the male offspring. Heifer milk production was not impacted (P > 0.10) by the dietary treatments or sex of the offspring in any of the periods evaluated (days 30 and 210). Hence, supplementing CSSO to Nellore heifers during the second and third trimester of gestation altered offspring BW up to 120 days after birth, suggesting programming effects on postnatal offspring growth resultant from the CSSO treatment. Male offspring were heavier from birth to weaning compared with female offspring. These outcomes indicate that supplementing CSSO to Nellore heifers during pregnancy might be a feasible alternative to optimize offspring productivity, and carcass merit in grazing systems.