Effects of recombinant bovine somatotropin administration at breeding on cow, conceptus, and subsequent offspring performance of beef cattle1

Abstract

The effects of administration of recombinant bovine ST (bST) on plasma hormone concentrations of cows, conceptus development, and postnatal calf performance were examined. Lactating beef cows ( = 190) were exposed to a fixed-time AI (TAI) protocol from d -10 to 0 (TAI on d 0). Cows were blocked by breed and stratified by days postpartum and then randomly assigned to receive, subcutaneously 1) 2 injections of saline (1 mL of 0.9% saline), 1 on d 0 at TAI and a second injection on d 14 (CTRL; = 53); 2) an injection of 325 mg of bST on d 0 and a saline injection on d 14 (bST0; = 48); 3) a saline injection on d 0 and an injection of 325 mg of bST on d 14 (bST14; = 49); or 4) 2 injections of 325 mg of bST, 1 on d 0 and a second injection on d 14 (bST0+14; = 40). Pregnancy status, crown-to-rump length (CRL) on Day 35, and crown-to-nose length (CNL) on Day 65 were determined via transrectal ultrasonography. Blood samples were collected on d 0, 7, 14, 21, 35, and 65, relative to TAI, to determine plasma concentrations of progesterone (P4), IGF-1, and pregnancy-specific protein B (PSPB) and also on d 18 and 21 for isolation of peripheral blood leukocytes for RNA extraction and measurement of interferon-stimulated genes transcript abundance. Individual calf BW was determined at birth and every 30 d until weaning. A subset of 24 calves was randomly selected for liver biopsies at birth to determine mRNA expression of target genes. Administration of bST to cows increased ( < 0.0001) concentrations of plasma IGF-1 for 14 d after injection compared with CTRL but did not affect fetal CRL and CNL ( = 0.23). Cows receiving bST only on d 0 had a greater ( = 0.05) transcript abundance in myxovirus resistance 2 on d 21 compared with 2bST cows (2.0- and 0.8-fold for bST0 and 2bST, respectively), whereas cows receiving bST14 and CTRL were intermediate (1.2- and 0.9-fold, respectively). Calf BW did not differ ( ≥ 0.100) among treatments on d 0, 30, 60, 90, 120, and 150 relative to birth. Injection of bST only on d 0 tended ( = 0.062) to increase calf liver mRNA expression of at birth compared with the calves born to cows in other treatments. Therefore, during a TAI protocol, the administration of 1 or 2 injections of 325 mg of bST to lactating beef cows enhanced their plasma concentrations of IGF-1 but failed to improve fetal size and plasma concentrations of maternal PSPB and P4 and had no effect on postnatal calf growth performance.

Post-transfer outcomes in cultured bovine embryos supplemented with epidermal growth factor, fibroblast growth factor 2, and insulin-like growth factor 1

“…In this study, concentrations of PSPB tended to follow a similar pattern, with the greatest average concentration across groups at day 28, and lowest concentrations at day 56. However, PSPB concentration levels were higher across days (~4-6 ng/ml) than previously reported concentrations (~2-3 ng/ml) analyzed by the same ELISA [154]. This difference could be attributed to the variation in cattle population.…”

“…This difference could be attributed to the variation in cattle population. Non-lactating beef cows were used in this study, whereas lactating beef cattle were used in the previous study [154]. The reduced PAG concentrations in lactating cattle may reflect the elevated degradation of PAG in the liver or clearance by the kidney [155].…”

Impact of slick hair trait on physiological and reproductive performance in beef heifers consuming ergot alkaloids from endophyte-infected tall fescue1

“…Serum concentrations of pregnancy-specific protein B (PSPB) were analyzed 28 d postbreeding (day 56) using the commercially available BioPRYN ELISA assay (Biotracking LLC; Moscow ID) as previously described by Mercadante et al (2016). All samples were run in a single assay and the intra-assay coefficient of variation was 3.88%.…”

Tracing Recombinant Bovine Somatotropin Ab(Use) Through Gene Expression in Blood, Hair Follicles, and Milk Somatic Cells: A Matrix Comparison

“…Three genes were used as endogenous controls to calculate the relative expressions of the other 15 candidate genes. The selection of reference and target genes was based on results observed in previous transcriptomics studies, where the administration of rbST and anabolic agents to cattle was evaluated [ 13 , 14 , 15 , 16 , 17 , 31 ]. Gene-expression assays were carried out with a TaqMan ® OpenArray ® system (Applied BiosystemsTM, Thermo Fisher Scientific), involving a nanoliter high-throughput real-time PCR platform where 3072 reactions were performed simultaneously in the same OpenArray ® plate, and the primers and TaqMan ® probes were preloaded in the plates by the company.…”