Predictors of the ovarian superstimulatory response and oocyte collection in prepubertal heifers.

The objectives were to investigate the relationships between antral follicle counts and plasma AMH and FSH at the time of follicular wave emergence in prepubertal calves, and to determine the effects of age and duration of gonadotropin treatment on the ovarian superstimulatory response in pre- and post-pubertal heifers. Hereford crossbred prepubertal (Replicate 1 and 2, n = 20) and post-pubertal heifers (Replicates 1, n = 8; Replicate 2, n = 8) were assigned randomly to 2 treatment groups and given FSH for either 4 or 7 d (25 mg pFSH im at 12-h intervals). Prepubertal heifers were first treated at 4 mo and again at 7 mo of age. Blood samples were collected immediately before the first FSH administration, that was initiated 36 h after follicular ablation. An LH treatment (12.5 mg im) was given 12 h after the last FSH injection. Follicular fluid and cumulus-oocyte complexes (COC) were collected 24 h after LH treatment. At wave emergence, the number of follicles ≥1 mm (AFC, 31.1 ± 4.0 vs 16.2 ± 1.8; P < 0.001) and the plasma concentrations of AMH (606.4 ± 90.5 vs 279.6 ± 28.3 pg/mL; P = 0.001) were higher at 4 than at 7 mo of age, while plasma FSH concentrations did not differ between ages. At oocyte collection, a higher number of follicles ≥6 mm were observed in prepubertal calves at 4 mo of age and post-pubertal heifers than in calves at 7 mo of age (32.4 ± 5.4 and 22.0 ± 2.3 vs 14.9 ± 2.0, respectively; P = 0.003). Intrafollicular concentrations of estradiol were lower (23.7 ± 4.5 vs 144.0 ± 29.5 ng/mL; P < 0.0001) and of progesterone tended to be higher (217.5 ± 29.3 vs 157.0 ± 33.9 ng/mL; P = 0.07) in the 7- than in the 4-d groups. A greater number of COC was collected from calves at 4 mo of age and heifers than the 7-mo-old calves (13.4 ± 2.6 and 6.0 ± 1.0 vs 5.8 ± 1.1, respectively; P = 0.008). Overall, the 7-d FSH treatment tended to result in a greater proportion of expanded COC than the 4-d treatment in calves (50.1 ± 7.7 vs 31.9 ± 6.8%; P = 0.07). In summary, there was a positive relationship between AFC and plasma AMH concentrations at the time of wave emergence. A higher AFC was observed in calves at 4- than 7-mo of age, which resulted in greater ovarian response to gonadotropin treatment. Following an exogenous LH stimulus, COC maturation rates were greater in the 7-d than in the 4-d FSH treatment groups, resulting in collection of a higher proportion of fully expanded COC.

Combinação de butafosfan e cianocobalamina no metabolismo da glicose em vacas leiteiras após o parto / Combined of butaphosphan and cyanocobalamin on the glucose metabolism of dairy cows after calving

A hipótese deste estudo é de que o uso da combinação de butafosfan e cianocobalamina pode melhorar a resistência periférica à insulina, aumentar a quantidade de glicose disponível para a glândula mamária e a produção de leite. Assim, o objetivo foi investigar os efeitos combinados de butafosfan e cianocobalamina sobre o metabolismo da glicose em vacas leiteiras no período pós-parto. Vinte e uma vacas leiteiras foram divididas em dois grupos: grupo controle (CON, n= 11), que recebeu cinco aplicações de solução salina (20mL / animal 0,9% NaCl), e grupo Catosal(r) (ABC, n= 10), que recebeu cinco aplicações de 20mL de uma solução contendo as substâncias butafosfan e cianocobalamina (B12 Catosal(r), 100mg da substância butafosfan e 50µg de cianocobalamina por mL). As aplicações foram realizadas por via intramuscular, nos dias sete, 12, 17, 22 e 27 pós-parto. As amostras de sangue foram coletadas para a avaliação das concentrações plasmáticas de fósforo, glicose, ácidos graxos não esterificados (AGNE), albumina, aspartato aminotransferase (AST) e creatina quinase (CK). Nos dias oito e 28 pós-parto, os animais foram pesados e submetidos aos testes de tolerância à glicose e à insulina. O tratamento promoveu perda de peso (ABC 40,4kg, CON 10,73kg, P<0,05) e aumento da AST (ABC 62,92 ±3,31U/L, CON 53,11±3,49 U / L, P<0,05) e dos níveis de CK (ABC 134,09± 19,08U / L, CON 79,43 ± 18,27U / L). Os grupos não diferiram quanto ao metabolismo (área sob a curva) da glicose nos dias oito e 28, porém os animais tratados tiveram um aumento na glicemia (P<0,05) no dia 28 pós-parto (97,54 ± 8,54mg / dL), após a administração de insulina, em comparação ao dia oito (83,01 ± 8,54mg / dL). Assim, pode-se concluir que a combinação de butafosfan e cianocobalamina melhora a adaptação do metabolismo da glicose em vacas leiteiras no início da lactação.(AU)

The hypothesis of this study is that the combined use of butaphosphan and cyanocobalamin could enhance peripheral insulin resistance, increasing the amount of glucose available for the mammary gland and milk production. Thus, our aim was to investigate the combined effects of butaphosphan and cyanocobalamin on the glucose metabolism in dairy cows during the postpartum period. Twenty one dairy cows were divided into two groups: Control Group (CON, n= 11), that received 5 injections of saline solution (20mL/animal 0.9 % NaCl), and Catosal group (ABC, n= 10) which received 5 injections of 20mL of a Butafosfan and Cyanocobalamin solution (Catosal(r) B12, 100mg of Butafosfan and 50µg Cyanocobalamin for mL). The injections were performed by intramuscular route, on days 7, 12, 17, 22 and 27 postpartum. Blood samples were taken on these days to evaluate plasma concentrations of phosphorus, glucose, non-esterified fatty acids (NEFA), albumin, aspartate aminotransferase (AST) and creatine kinase (CK). On days 8 and 28 postpartum, the animals were weighted and subjected to the glucose tolerance and insulin challenge tests. The treatment promoted weight loss (ABC 40.4kg, CON 10.73kg, P< 0.05) and increased AST (ABC 62.92 ±3.31U/L, CON 53.11 ±3.49U/L, P< 0.05) and CK levels (ABC 134.09 ±19.08U/L, CON 79.43 ±18.27U/L). Glucose metabolism (area under the curve) did not differ (P> 0.05) among groups on days 8 and 28; however, ABC animals showed higher serum glucose levels (P< 0.05) after insulin administration on day 28 postpartum (97.54 ±8.54mg/dL) when compared to day 8 (83.01 ±8.54mg/dL). It could be concluded that the combined use of butaphosphan and cyanocobalamin interferes positively with the adaptation of glucose metabolism in dairy cows in early lactation.(AU)