Effect of prepartum somatotropin injection in late-pregnant Holstein heifers on metabolism, milk production and postpartum resumption of ovulation

Abstract

The aim of this study was to determine the effect of prepartum somatotropin injection in late-pregnant Holstein heifers on metabolism, milk production and resumption of postpartum ovulation. For this study, 31 late-pregnant Holstein heifers were used. The heifers were assigned randomly into two treatments: (1) 500 mg sc injections of somatotropin (somatotropin treatment, n 5 15) at 235 and 221 days, and, if pertinent, at 27 days from expected calving date and (2) no treatment (control group, n 5 16). Blood samples were collected weekly from 25 to 7 weeks after calving. Heifers with progesterone concentrations in plasma above 1 ng/ml in two consecutive postpartum samples were considered as having resumed ovarian activity. A higher proportion (P 5 0.04) of heifers treated with somatotropin resumed ovarian activity in the first 7 weeks post partum (73.3%; 11/15) compared with the control group (37.5%; 6/16). A higher number (P 5 0.02) of heifers in the somatotropin treatment group also ovulated during the first postpartum follicular wave (53.3%; 8/15) compared with the control group (12.5%; 2/16), as indicated by the number of heifers ovulating in the first 3 weeks post partum. Pregnancy rate was not affected by treatments (P . 0.10) and averaged 40.0% (6/15) in somatotropin-treated and 25.0% (4/16) in control heifers when evaluated up to 150 days in milk. Somatotropin treatment increased the average daily milk production by 2.8 kg/cow per day (P , 0.0001) and reduced the somatic cell count (P 5 0.009). Plasma IGF-I was higher (P , 0.05) for somatotropin-treated heifers in the prepartum period. Insulin and body condition score were higher (P , 0.05) and non-esterified fatty acids were lower (P , 0.05) for somatotropin-treated cows in the early postpartum period. In conclusion, somatotropin injection during the prepartum period in late-pregnant Holstein heifers was able to increase the proportion of heifers resuming ovarian activity early post partum, inspite of higher milk production.Keywords: bST, dairy heifers, IGF-I, ovarian activity, primiparous ImplicationsPhysiological changes during the transition period can have a great impact on health and performance. In our study, prepartum injection of somatotropin reduced negative energy balance (NEB) intensity as indicated by several metabolic markers evaluated in the postpartum period. A more intense NEB is usually associated with a delay in resumption of normal ovarian function. In this way, we observed a higher proportion of somatotropin-treated heifers ovulating earlier.Moreover, cows treated with somatotropin prepartum increased milk production. Along with earlier resumption of estrous cycles, this strategy can have an important impact on farm profitability. IntroductionDuring the early postpartum period, high-producing cows experience a period of negative energy balance (NEB) that occurs as the requirements for milk production exceed the -E-mail: augusto.schneider@live.com 935 energy obtained through feeding (Butler, 2003). In early postpartum dairy cows, the du...

Prepartum administration of recombinant bovine somatotropin (rBST) on adaptation to subclinical ketosis of the ewes and performance of the lambs

“…Vet. Zootec., v.67, n.1, p.103-108, 2015 response to rbST, allows increased milk production during the subsequent lactation (Stelwagen et al, 1993;Schneider et al, 2011). This effect is confirmed by the absence of significant difference between groups at birth, indicating that the difference was obtained during the development of the lambs by greater body weight gain in the first days of life.…”

“…With the administration of rbST in the prepartum of ewes it was possible to observe changes in the activity of the enzyme GGT after induction of sub-clinical ketosis. It is important to note that the level of GGT in the rbST group was lower than in the control group, thus emphasizing the positive effect of rbST in reducing liver damage due to excessive lipid mobilization (Schneider et al, 2011), after induction of subclinical ketosis.…”

“…The injection of bovine recombinant somatotropin (rbST) or growth hormone (GH) has been used as a strategy to prevent ketosis by adapting the ewe to the high amount of lipid mobilization (McGuffey et al, 1991). In dairy cows, when injected in the prepartum period, rbST increases blood glucose and IGF-I concentrations in the prepartum period and reduces NEFA concentrations during the postpartum period, which results in increased dry matter intake and milk production (Putnam et al, 1999;Pauletti et al, 2005;Schneider et al, 2011). Moreover, Stelwagen et al (1993) demonstrated that there is a positive effect of GH prepartum rbST injection on mammary gland development and milk production in sheep, due to increased cell proliferation stimulated by the IGF-I produced in response to rbST.…”

Effect of prepartum somatotropin injection in late pregnant Holstein heifers with high body condition score on metabolic parameters, resumption of ovulation and milk production

“…In addition, IGF-I acts on the growth and differentiation of antral follicles (Rivera and Fortune 2003). These studies indicate that pre-partum injection of somatotropin is a potential tool to improve metabolic adaptation of transitional dairy cows, and thus can have a positive impact on early post-partum ovulation as demonstrated for lean cows treated with pre-partum somatotropin (Schneider et al 2011). On the other hand, studies investigating the pre-partum use of somatotropin uses in heifers with high body condition score are still needed.…”

“…Therefore, strategies that minimize NEB and BCS loss in the early postpartum period could have a positive impact on the timing of the first ovulation and the conception rate. Administration of somatotropin in the peripartum period induced an increase in serum insulin-like growth factor I (IGF-I) (Putnam et al 1999;Carriquiry et al 2009;Schneider et al 2011). Circulating IGF-I plays an essential role in reproduction (Velazquez et al 2008).…”