Effects of supplementation of grazing Nellore cows with ß-carotene and vitamins A + D3 + E + biotin on follicle diameter, oestrus, establishment of pregnancy, and foetal morphometry.

The objectives of this experiment were to evaluate the effects of supplementation of Nellore (Bos indicus) cows with ß-carotene + vitamins A + D3 + E + biotin on body condition score (BCS), oestrus, pregnancy, and foetal morphometry. Lactating cows (n = 497) from two herds were balanced for BCS and calving period [early calving (EC); late calving (LC)] and were assigned randomly to: Control (n = 251)-supplementation with a mineral supplement; and SUP (n = 246)-supplementation with the mineral supplement fed to control + ß-carotene (150 mg/day) + vitamin A (40,000 IU/day) + vitamin D3 (5000 IU/day) + vitamin E (300 mg/day) + biotin (20 mg/day). Cows were supplemented from Days -30 to 30 (Day 0 = timed artificial insemination; TAI). Pregnancy was diagnosed 30 days after TAI and foetal crown-rump distance and thoracic diameter were measured at 30 and 77 days of gestation. Cows in the SUP treatment were more likely to have BCS ≥3.0 on Day 0 (63.0 ± 3.1 vs. 60.2 ± 3.1; p < .01) and were more likely to gain BCS from Days -30 to 30 (57.7 ± 3.3 vs. 44.1 ± 3.3%; p < .01). Fewer LC cows in the SUP treatment were detected in oestrus at the time of the first TAI (Control: LC: 75.4 ± 4.4 vs. SUP: LC: 64.0 ± 5.2 vs. Control: EC: 65.3 ± 4.0 vs. SUP: EC: 71.8 ± 3.7; p = .04). There was a tendency for the SUP treatment to increase pregnancy to the first TAI (64.2 ± 3.0 vs. 56.6 ± 3.1%; p = .08). A greater percentage of SUP cows was detected in oestrus at the time of the second TAI (70.1 ± 5.0 vs. 52.3 ± 4.8%; p = .01). The SUP treatment increased pregnancy to the second TAI among LC cows (SUP: LC: 75.9 ± 8.0% vs. Control: LC: 50.0 ± 8.3% vs. Control: EC: 52.0 ± 5.9% vs. SUP: EC: 41.4 ± 6.5%; p = .02). The SUP treatment increased foetal size (crown-rump; p = .04 and thoracic diameter; p < .01) at 30 days of gestation and, despite decreasing crow-rump length at 77 days after the first TAI among EC cows (p < .01), it increased the thoracic diameter at 77 days after the first TAI independent of calving season. Our results support that pregnancy establishment and foetal growth can be improved when grazing Nellore cows are supplemented with ß-carotene and vitamins A + D3 + E + biotin.

Influência da vacinação materna na transferência de imunidade passiva contra as viroses respiratórias dos bovinos / Influence of maternal vaccination for the passive immune transfer against bovine respiratory viruses

O objetivo deste estudo longitudinal foi avaliar a influência da vacinação materna na transferência de anticorpos (ACs) contra as viroses respiratórias em bezerros. Para tanto, vacas e bezerros foram distribuídos em dois grupos conforme a realização (VAC, n=6) ou não (NVAC, n=4) da vacinação no pré-parto. Amostras sanguíneas foram obtidas após a parição (D0); em seguida, apenas os bezerros foram acompanhados até D180. ACs séricos foram determinados pela vírus-neutralização (VN) contra BVDV, BoHV-1, BRSV e BPI3-V. Vacas VAC apresentaram diferenças para ACs contra BoHV-1 (P=0,01) em D0. As frequências (%) de bezerros soropositivos para BoHV-1 foram maiores em VAC do D2 ao D120; para BRSV em D4, D8, D10 e D150 (P≤0,08); medianas de ACs contra BoHV-1 em VAC do D2 ao D120 (P=0,08). A vacinação das vacas no pré-parto foi fundamental para a transferência e a duração de ACs contra BoHV-1 e BRSV, porém o protocolo adotado não foi eficiente para o aumento de ACs para BVDV e BPI3-V. A eficácia parcial da vacinação materna não inviabiliza a sua recomendação devido à importância do Herpesvírus e do BRSV na DRB, porém estratégias para a melhoria nas respostas imunes contra as demais viroses devem ser estabelecidas.(AU)

The aim of this longitudinal research was to evaluate the influence of maternal vaccination for the passive immune transfer of antibodies (Abs) against respiratory viruses in calves. Therefore, cows and calves sourced from two groups according to having received (VAC, n=6) or not (NVAC, n=4) of vaccination at pre-partum period. Blood samples of cows and calves harvested after parturition (D0), and then only calves followed until the age of 180 days. Abs performed by virus neutralization (VN) against BVDV, BoHV-1, BRSV and BPI3-V. VAC cows presented differences for Abs against BoHV-1 (P=0.01) in D0. Frequencies (%) of seropositive VAC calves for BoHV-1 were higher in D2 to D120; to BRSV D4, D8, D10 and D150 (P≤0.08); higher medians of Abs against BoHV-1 in VAC at D2 up to D120 (P=0.08). Partial efficacy of vaccination of cows does not impair its recommendation due to the importance of Herpesvirus and BRSV in BRD, but strategies for improvement in immune responses against other viruses should be established.(AU)

Efficacy of ampicillin trihydrate or ceftiofur hydrochloride for treatment of metritis and subsequent fertility in dairy cows.

Our objectives were to evaluate the efficacy of ampicillin trihydrate for the treatment of metritis in dairy cows compared with ceftiofur hydrochloride and the subsequent effects on pregnancy at first insemination (P/AI). Cows in the first 12 d in milk (DIM) with a uterine discharge score of 5 (watery, reddish or brownish discharge of foul smell) and rectal temperature <39.5°C were diagnosed with metritis based on the fetid discharge, and cows with metritis and rectal temperature ≥39.5°C were diagnosed as having puerperal metritis. Cows with metritis (n=528) were blocked by parity and type of metritis as fetid discharge or puerperal metritis and, within each block, assigned randomly to receive 11mg/kg of ampicillin (n=259) or 2.2mg/kg of ceftiofur (n=269) once daily for 5 d. Day of diagnosis of metritis was considered study d 1. A cohort of 268 cows without metritis was selected randomly at 12 DIM. Rectal temperature was measured in cows with metritis on study d 1 to 7, and 12, and vaginal discharge was scored on study d 5, 7, and 12. Metritis cure was characterized by vaginal discharge score of <5 or by vaginal discharge score of <5 and no fever. At 32±3 DIM, vaginal discharge was scored for diagnosis of purulent vaginal discharge. At 39±3 DIM, endometrial cytology was performed. At 53±3 and 67±3 DIM, ovaries were scanned to determine estrous cyclicity. Pregnancy was evaluated after the first AI. Cure of metritis based on vaginal discharge <5 was greater for ampicillin than ceftiofur on d 5 (37.1 vs. 25.2%) and 7 (57.2 vs. 46.3%), but not on d 12 (82.0 vs. 85.0%). Cure of metritis based on vaginal discharge <5 and no fever was greater for ampicillin than for ceftiofur only on d 7 (50.4 vs. 37.9%), but not on d 5 (23.1 vs. 17.6%) and 12 (66.1 vs. 67.4%). Cows with puerperal metritis had reduced cure compared with cows with fetid discharge on d 5 (30.5 vs. 12.8%), 7 (55.2 vs. 33.6%), and 12 (72.0 vs. 61.1%). The proportion of cows with fever on any day after therapy started did not differ between treatments. Fifty-three percent of cows with metritis based on fetid discharge developed fever after initiating antimicrobial therapy. Cows receiving ampicillin had less prevalence of purulent vaginal discharge than those treated with ceftiofur (57.7 vs. 67.8%), but they were both greater than cows without metritis (21.9%). Prevalence of cytological endometritis did not differ between ampicillin and ceftiofur (30.0 vs. 25.4%), but they were both greater than cows without metritis (14.5%). The proportion of estrous cyclic cows (75.0%) and P/AI did not differ among treatments (ampicillin=28.0% vs. ceftiofur=28.3% vs. without metritis=30.5%). Clinical cure was faster for ampicillin than for ceftiofur, but on study d 12 both treatments resulted in similar cure. Clinical cure was less for cows with puerperal metritis than for cows with fetid uterine discharge. Despite differences in uterine health, P/AI at the first insemination did not differ among treatments.