Progesterone and Luteinizing Hormone Concentration in Serum of Pregnant Gilts on Different Levels of Feed Consumption

Abstract

luteinizing hormone concentration in serum of pregnant gilts on different levels of feed consumption. Can. J. Anim. .Blood serum progesterone (P) and luteinizing hormone (LH) were determined in 31 Lacombe gilts at a 3-to 4-day interval from I 0 to 56 days of pregnancy.

Beneficial effects of a high fibre diet on oocyte maturity and embryo survival in gilts

“…It is likely that the increase in LH pulse frequency arises as a consequence of lower circulating steroid concentrations providing reduced negative feedback to the hypothalamus. Studies involving altered feed intake have consistently reported an inverse relationship between the plane of nutrition and circulating steroid concentrations in the pig (Dyck et al 1980, Ferguson et al 2003. This relationship is thought to be attributed to increased steroid metabolism arising from increases in hepatic size, hepatic mixed function oxidase activity and portal blood-flow in well-fed animals (Prime & Symonds 1993, Ashworth et al 1999a).…”

Dietary energy and protein intake, plasma progesterone and embryo survival in early pregnancy in the gilt

“…As high feed intakes from dl to 10, but not from dll to 2O after mating, reduced embryonic survival in gilts at d30 (Dyck and Strain 1983) a critical period over which level of feeding affects embryo survival may exist. The mechanisms by which altered feed intake influences embryo survival are not known; although a high plane of nutrition reduced serum progesterone in gilts (Dyck et al 1980), no difference in embryo survival was seen at d60 of gestation. A nutritionallydependent depression in plasma progesterone may be due to alterations in the metabolic clearance rate of plasma steroids by the liver (Kirkwood and Aherne 1985).…”

“…In the only other study in which plasma progesterone concentrations were examined in relation to increased feed intake (Dyck et al 1980) …”

Efeito do fracionamento da ração diária sobre a concentração sérica de progesterona em porcas gestantes

“…Diferenças na concentração de progesterona circulante atribuídas ao excesso de energia na ração no início da gestação foram observadas por Dick et al (1980) e Jindal et al (1996 em experimentos com marrãs. Prime et al (1988), ao estudarem porcas pluríparas, não observaram diferenças na concentração de progesterona em fêmeas submetidas a tratos com diferentes quantidades de ração.…”

“…A influência da concentração energética no período inicial de gestação sobre a sobrevivência embrionária tem sido estudada em fêmeas suínas (Dick et al, 1980; Ashworth, 1991;Jindal et al, 1997). Entretanto o manejo alimentar e suas implicações em características reprodutivas só recentemente começaram a ser estudados em bovinos (Vasconcelos, 1998) e suínos (Bandeira, 1999).…”