Effects of post-AI supplementation with Ca salts of soybean oil on ovarian and pregnancy development in Bos indicus beef cows

• Published in: Journal of animal science Vol. 94; pp. 555 - 556
• Main Authors: Cipriano, R S, Cerri, R L A, Cooke, R F, Rodrigues, A D P, da Silva, L G T, Schumaher, T F, Biehl, M V, Cruppe, L H, Bohnert, D W, Pires, A V
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01.10.2016
• Subjects: Artificial insemination; Beef; Beef cattle; Bos taurus indicus; Calcium; Corn; Corpus luteum; Embryos; Gestation; Kaolin; Oils & fats; Ovulation; Pasture; Pregnancy; Proteins; Salts; Soybean oil; Soybeans; Studies; Supplements; Ultrasound; Uterus; Vegetable oils
• ISSN: 0021-8812; 1525-3163

The objective of this experiment was to compare corpus luteum (CL) and pregnancy development in beef cows supplemented or not with Ca salts of soybean oil for 21 d (CSSO) beginning after timed-AI. One hundred lactating multiparous Nelore (Bos indicus) cows (BW = 430 ± 5 kg, BCS = 2.87 ± 0.02; age = 8.5 ± 0.2 yr; days post-partum = 152 ± 1 d) were inseminated on d 0 of the experiment, and divided into 20 groups of 5 cows/group. Groups were randomly assigned to receive (as-fed basis) 100 g of protein-mineral mix + 100 g of ground corn per cow/d, in addition to: 1) 100 g/cow daily of CSSO (n = 10), or 2) 100 g/cow daily of kaolin (CON; rumen-inert indigestible substance; n = 10). Groups were maintained in 4 Panicum maximum pastures (5 groups from the same treatment within each pasture) with ad libitum access to forage. However, groups were segregated daily and offered treatments individually during the experimental period (d 0 to 21). Blood samples were collected and transrectal ultrasonography was performed to verify ovulation and corpus luteum (CL) volume immediately before AI (d 0), on d 7, and 15. Immediately after ultrasonography on d 15, 60 cows (30 cows/treatment, 3 cows/group) diagnosed without the presence of a CL on d 0, but with a CL greater than 0.38 cm3 in volume on d 7 and 15, were assigned to embryo collection via uterine flushing with PBS. On d 30, final pregnancy status was determined via transrectal ultrasonography. No treatment differences (P = 0.68) were detected on dominant follicle diameter on d 0. However, mean CL volume on d 7 and 15 was greater (P = 0.04) for CSSO vs. CON cows (3.2 vs. 2.7 cm3, respectively; SEM = 0.2). No treatment differences were detected (P ≥ 0.85) for the proportion of cows that had an embryo on d 15 (40.0 vs. 39.2% for CSSO and CON cows, respectively; SEM = 8.9) or diagnosed as pregnant on d 30. However, embryos collected from CSSO cows were longer (P = 0.04) compared with embryos collected from CSSO cohorts (2.57 vs. 1.15 cm, respectively; SEM = 0.59). In summary, supplementing beef cows with 100 g of CSSO beginning after AI increased CL and embryo development by d 15 of gestation.