Response of Dairy Cows to High Doses of a Sustained-Release Bovine Somatotropin Administered During Two Lactations. 2. Health and Reproduction

Abstract

Eighty-two lactating Holstein cows in their first, second, or third lactation received either one, three, or five concurrent i.m. injections of a unit dose (.6 g) of zinc methionyl bST (sometribove) or five doses of the vehicle. Injections were given at 14-d intervals from 60 +/- 3 d postpartum until the end of lactation or necropsy. Thirty-eight animals were continued on treatment for a 2nd yr. Sometribove did not affect the incidence of ketosis, milk fever, tetany, or pneumonia. Digestive disorders, primarily cows going off feed, were increased by bST during yr 1 only. The incidence of lameness was increased by bST in some time frames because of an increase in the 3.0-g bST group. Lameness was not associated with treatment-specific histopathologic changes or with abnormalities in cartilage or bone. Reproductive health generally was unaffected by treatment, but delayed conception and increased incidence of abortion were noted. Incidence of cystic ovaries was unaffected by bST. Pregnancy rates were decreased during the 100-d breeding interval of yr 1 but not during the 215-d interval of yr 2. The incidence of clinical mastitis was increased by bST, primarily at the 3.0-g dose. During the 2-yr study, 0, 3, 3, and 2 cows died or became moribund on 0, .6, 1.8, and 3.0 g of bST, respectively. Health issues identified for further evaluation included lameness and clinical mastitis for the 3.0-g group and early removal from the herd and decreased reproductive performance for all bST groups. Bovine somatotropin caused no treatment-specific toxic effects in dairy cows even at 3.0 g every 14 d.

Physiological responses of dairy animals to recombinant bovine somatotropin: A review

“…At the same time, Esteban et al (1994) reported that because rates of dystocia and retained fetal membranes increased in control and rbSTtreated cows, exposure to rbST was probably not directly related to those changes. The observation that rbST did not increase the risk for a cow developing cystic structures during the early postpartum period of the following lactation agreed with similar finding reported by Cole et al (1992). Also, Lucy et al (1991) noticed that rbST may have a direct effect on ovarian tissues.…”

Effect of recombinant bovine somatotropin (rbST) treatment on follicular population and development in non-lactating dairy cows

“…Previous studies showed that rbST treatment in postpartum dairy cows can negatively affects estrous expression and reproductive performance (Cole et al, 1992;Kirby et al, 1997a;Santos et al, 2004). Nevertheless, prepartum rbST treatment improved ovulation and steroidogenesis of the first postpartum dominant follicle in dairy cows (Schneider et al, 2012;Acosta et al, 2017).…”

“…Peripartum rbST treatment promotes an increase in serum IGF-I concentration (Carriquiry et al, 2009) and glucose, and a decreased serum non-esterified fatty acids and beta-hydroxybutyrate concentration (Putnam et al, 1999). Despite positive effects on lactation, some studies suggest that rbST negatively affects reproductive performance in dairy cows in the long term (Cole et al, 1992;Kirby et al, 1997b;Santos et al, 2004). Interestingly, the prepartum treatment with rbST was associated with a shorter interval between calving and first ovulation in dairy cows (Schneider et al, 2012).…”

Influência da aplicação da somatotropina recombinante bovina (rBST) no lipidograma e composição do leite de bubalinos da raça Murrah em lactação

“…Do ponto de vista reprodutivo, em revisão de literatura sobre a utilização de rBST em vacas lactantes, Mattos (1998) (EPPARD et al, 1987;COLE et al, 1992;BAUMAN, 1999), enfermidades podais (CHALUPA et al, 1988) ou enfermidades hepáticas , já Etherton e Bauman (1998) afirmam que a dependência do estágio de lactação, a dose de somatotropina utilizada e o balanço energético das vacas, poderiam ser relacionados a transtornos na saúde desses animais.…”