Maternal metabolic disruptions, such as ketosis, can have adverse effects on fetal development and influence postnatal factors. Twelve Holstein calves were randomly enrolled in this study at birth and monitored until 8 weeks of age. The study was conducted from fall 2018 until spring 2019. After completing the data collection period, calves were classified according to their respective dams ketotic condition after parturition. This classification was based on dam blood β-hydroxybutyrate < 1.4 mmol/L nonketotic (NONKET; n = 6 calves) or ≥1.4 mmol/L subclinical-ketotic (SK; n = 6 calves). SK calves had greater birth body weight (p = 0.05) but exhibited a slower growth rate compared to NONKET calves from 1 to 8 weeks (p = 0.02). At birth, SK calves had lower (p < 0.01) levels of non-esterified fatty acids and bilirubin compared to NONKET calves. Analysis of feces alpha diversity indicates that by 3 weeks, NONKET calves had greater diversity, richness, and evenness. Butyricicoccus pullicaecorum and Gallibacterium anatis were more abundant in SK calves (p < 0.05) at 3 weeks. In contrast, NONKET calves had a greater (p < 0.05) abundance of Sharpae azabuensis at 3 weeks. These findings suggest that subclinical ketosis in cows can impact the in-utero development, postnatal growth, and maturing gut microbiome of their offspring.

This study aimed to evaluate embryo yield in Holstein heifers superovulated with a single injection of recombinant, long-acting human follicle-stimulating hormone (rFSH) versus multiple injections of pituitary-derived follicle-stimulating hormone (FSH). In Experiment 1, heifers were assigned randomly to one of 4 experimental groups: Control (280 mg of pituitary derived FSH; six injections of 40 mg and two injections of 20 mg, each ~12 h apart, n = 16); rFSH1 (50 μg of FSH analog protein, n = 16); rFSH2 (75 μg of FSH analog protein, n = 16) or; rFSH3 (100 μg of FSH analog protein, n = 16). The rFSH was administered as a single injection. Estrous cycles were presynchronized with gonadorelin acetate (GnRH) and an intra-vaginal progesterone insert (CIDR) on d -8, followed by cloprostenol sodium (PGF_2α) on d -3 and d -2 with removal of the CIDR, and GnRH on d 0. On d 5, ovarian follicles ≥ 5 mm in diameter were ablated by transvaginal ultrasound-guided aspiration. On d 6.5, heifers received a CIDR and the rFSH or the first injection of pituitary-derived FSH. On d 9, heifers received two injections of PGF_2α, 12 h apart. On d 10.5, the CIDR was removed, and on d 11, heifers received a GnRH injection. Heifers were AI-inseminated 12- and 24-hours post-GnRH injection, and uterine contents were flushed trans-cervically on day 18 (7 d after the GnRH injection). Ovarian follicles ≥ 5 mm and corpora lutea were counted via ultrasound on days 5, 9, and 18. In Experiment 1, group did not affect (P = 0.52) the number of follicles ≥ 5 mm (Control = 15.9 ± 1.2; rFSH1 = 17.5 ± 1.3; rFSH2 = 17.1 ± 1.3; rFHS 3 = 18.6 ± 1.4 follicles) or the number of corpora lutea (P = 0.96) on d 9 (Control = 1.1 ± 0.3; rFSH1 = 1.1 ± 0.3; rFSH2 = 1.1 ± 0.3; rFSH3 = 0.9 ± 0.2). Furthermore, there was no effect (P = 0.28) of rFSH dose on freezable embryos (grade 1 and 2 embryos) collected on d 18 (Control = 4.7 ± 1.1; rFSH1 = 4.7 ± 1.2; rFSH2 = 4.4 ± 1.1; rFSH3 = 2.6 ± 0.7 embryos). In Experiment 2, Control (n=8) and rFSH1 (n=16) groups were repeated in 3 replicates using the same protocols as Experiment 1. Consequently, Results showed that rFSH produced fewer total number of ova/embryos (Control = 9.9 ± 1.5 vs. rFHS1 = 5.9 ± 0.9, P = 0.04) and fewer freezable embryos (Control = 5.3 ± 1.0 vs. rFSH1 = 1.4 ± 0.3, P < 0.01). In conclusion, the single rFSH injection effectively induced superovulation; however, its repeated use reduced embryo production.

Hormonal growth-promoting implants are known to enhance growth performance in beef cattle, but their influence on vaccine response has not been studied extensively. Herein, we evaluated the growth performance and immunity of beef steers under different hormonal implant treatments and timing of booster vaccination. Fifty-nine crossbred beef calves were stratified by body weight (BW) and age (109 ± 18.9 kg and 70 ± 8 d of age) and randomly distributed into a completely randomized design with a 3 × 2 factorial arrangement to one of three implant treatments: (i) no implant (CON); (ii) short-term payout period implant (Synovex C; ST); or (iii) long-term payout period implant (Synovex One Grower; LT), and to one of the booster vaccination groups; at weaning (WV) or 7 days post-weaning (PWV). From implantation, and initial vaccination (d 0) until weaning (d 114), calves were raised with their dams in a single pasture. After weaning, calves were allocated to a single pen until d 63 post-weaning (d 177). Body weight was recorded, and blood samples were collected to analyze insulin-like growth factor, cortisol, β-hydroxybutyric acid, non-esterified fatty acids, leptin, serum antibody titers, and complete blood cell count. Peripheral blood lymphocyte concentration was greater in CON compared with ST and LT (P < 0.01), and greater plasma leptin (P = 0.01) in ST compared to LT, while CON was intermediate. A treatment × timing of booster vaccination (P < 0.01) was observed with greater peripheral blood monocyte counts in LT-PWV compared to ST-PWV and CON-PWV. A timing of booster vaccination × day interaction (P = 0.01) was observed for plasma cortisol with smaller concentration in WV compared with PWV at booster vaccination and d 28 post-booster vaccination. No main effects of treatments or treatment interactions were observed for serum antibody titers (P > 0.20). Implant treatment did not affect weaning weights; however, calves implanted with LT were the heaviest on d 142 (P = 0.03) and tended to have greater final body weights at the end of the study (P = 0.07). In summary, implant strategy and booster vaccination timing affected metabolic and immune parameters in beef calves but did not influence serum antibody titers. Growth performance was not affected at weaning; however, long-term-implanted calves were heavier post-weaning and tended to have greater final BW, indicating improved growth without compromising antibody-mediated immune responses.