Manuel Murillo-Ortiz

Dietary Chemical Composition, Plasma Metabolites and Hormones in Range Goats

Abstract Juárez-Reyes, A.S., Nevarez-Carrasco, G., Cerrillo-Soto, M.A., Murillo-Ortiz, M., Luginbuhl, J-M., Bernal-Barragán, H. and Ramírez, R.G. 2008. Dietary chemical composition, plasma metabolites and hormones in range goats. J. Appl. Anim. Res, 34: 81–86. The objective of this study was to determine the monthly chemical composition of the diet consumed by range goats and plasma concentrations of glucose, urea, non-esterified fatty acids (NEFA), luteinizing hormone (LH), growth hormone (GH), insulin and progesterone (P4) during lactation (January-June). Three esophageally-cannulated female goats and twelve intact female goats (38±1.7 kg BW) were used to obtain extrusa and blood samples, respectively. Body weight decreased (P<0.05) by 12.5% during the period from January to May, whereas, in June goats lost 250 g d−1. There was a fall in nutrient density during May and June. With the exception of progesterone (0.1–0.6 ng ml−1), LH (7.1–11.0), GH (22.8–30) and insulin (0.6–1.8) increased (P<0.05) as lactation period progressed. It is concluded that plasma metabolite concentrations suggested that an energy supplementation schedule might be necessary during the early lactation period of goats. In addition, if harsh climatic conditions appear at the end of lactation, an increment of 70% in their energy maintenance requirements might be considered to avoid weight losses and to improve body condition of goats prior to breeding season.

Chemical composition, intake, ruminal fermentation, plasma metabolites and hormones in range steers

The objective of this study was to determine and compare, seasonally, across two consecutive years the chemical composition, intake, ruminal fermentation and plasma concentrations of glucose (G), urea-N (UN), non-esterified fatty acids (NEFA) and insulin in grazing steers. Data were analysed as repeated measures within a split plot design. The crude protein (CP), metabolisable protein (MP), neutral detergent fibre (NDF) and metabolisable energy (ME) were different within years and seasons (P<0.05). The values for organic matter intake (OMI), CP intake (CPI) and metabolisable protein intake (MPI) were greater in wet season (P<0.01). The pH values were not affected by years and seasons (P > 0.05). Ruminal ammonia (NH3–N) and volatile fatty acid (VFA) concentrations were lower during dry season than during wet season (P < 0.05). The plasma concentrations of G, UN, and insulin were higher in the wet season (P<0.05); however, the NEFA concentrations were higher in the dry season (P<0.05). The variables corresponding to chemical composition, intake, ruminal fermentation and concentrations of metabolites and hormones were affected over time by the years and seasons.