Efeito da administração da hormona PGF2α nos problemas pós-parto, mais concretamente na retenção placentária em bovinos leiteiros

Dissertação de Mestrado em Engenharia Zootécnica/Produção Animal

O efetivo bovino leiteiro está atualmente submetido a uma alta pressão genética e fisiológica para aumentar a produção leiteira, facto que também é explicado não só para aumentar a eficiência, mas também para responder ao fato de ter deixado de haver as cotas leiteiras. Essa pressão faz com que apareçam cada vez mais problemas de foro metabólico, derivado principalmente da resposta ao balanço energético negativo, existente no início da lactação, logo após o parto. Um dos grandes problemas associados a essa pressão genética é a retenção placentária, estado fisiológico de origem multifatorial e responsável por problemas reprodutivos e/ou metabólitos, podendo causar grandes dificuldades financeiras às explorações. Este ensaio teve como objetivo analisar a influência da administração da hormona PGF2α na prevalência de retenção placentária nos bovinos leiteiros. A hormona foi administrada na primeira hora após o parto, tendo como substância ativa o dinoprost (10

ABSTRACT - THE INFLUENCE OF THE ADMINISTRATION OF PGF2Α HORMONE ON PROBLEMS AFTER CALVING, SPECIFICALLY IN PLACENTAL RETENTION IN DAIRY CATTLE - The modern dairy cattle is currently subject to a high genetic and physiological pressure to increase milk production, a fact which is also explained not only to increase efficiency, but also to respond to the fact that milk quotas have ceased to exist. This pressure brings up more and more metabolic disorder problems, mainly derived from the reaction to negative energy balance, existing in early lactation, shortly after calving. A major problem associated with this genetic pressure is the placental retention, multifactorial origin of disease and responsible for reproductive and / or metabolic problems, that may lead to major financial difficulties to farm businesses. This study aimed to analyse the influence of the administration of PGF2α hormone in placental retention in dairy cattle. The hormone was administered within one hour after birth, with the active substance dinoprost (10 ml / dose). Apart from placental retention some parameters were also analysed that may be influenced by the hormone, such as milk production at 10, 20 and 30 days, in the occurrence of postpartum and fertility problems. It was also verified if the sex of the calves and the type of calving also influenced the retained placenta. The experiment was conducted at Herdade Vale da Lama d'Atela in Santarém, where I obtained a total of 105 calvings, 63 from multiparous cows and the remaining from primiparous cows. As to the primiparous, the hormone had virtually no effect, where the control group (n = 24) had 4 retentions, while the test group (n = 18) 2. The in multiparous control group (n = 32) had 5 retentions and the tested group (n = 31) only one, with a P value of 0.133. In milk production the tested group (n = 44) vs the control group (n = 50) presented an average production at 10,20 and 30 days of 27.9 ± 0.97 L vs. 25.9 ± 0.91L, 34.0 ± 19.1 vs 32.2 ± 1.11L L and 38.2 ± 35.4 vs 1:37 L ± 1.27L, with P values of 0.137, 0.264 and 0.129 respectively. With regard to the effect of the hormone in the occurrence of postpartum and fertility problems, it had a P value of 0.781 and 0.997. The sex of the calves and the type of birth had no effect on the incidence of retained placenta with P values of 0.886 and 0.526, respectively.