Compensatory gain of crossbred heifers supplemented in pastures under evaluation hormonal profile and blood parameters

Abstract

The objective of this experiment was to verify the effect of nutritional management that alternates periods of energy/protein restriction and refeeding of grazing crossbred heifers during their prepuberty on the hormonal profile and blood parameters. The study was conducted at Princesa do Mateiro farm in Ribeirão do Largo, in the southwest region of the state of Bahia. Twenty crossbred heifers 5/8 Dairy Guzerat x 3/8 Dutch with an average age of 12 months and average body weight of 187 ± 13.74 kg were used at the beginning of the experiment. It lasted 238 days, 14 out of them were for the animals’ adaptation. The animals were kept in rotational grazing of Brachiariabrizantha cv. Marandú pastures and randomly assigned to two treatments: Control (T100) = animals receiving concentrate supplement to supply 100% of the nutrients requirement to gain 750 g day-1 of live weight and Compensatory Nutrition (CN). The animals of the CN treatment alternated periods of Restriction (T80) = receiving concentrate supplement to meet 80% of the demand for nutrients of the (T100) and periods of Refeeding (T120) = getting concentrate supplement to supply 120% of the nutrient requirements of the (T100 The final plasma concentrations of IGF-I, glucose and urea were higher (P0.05). There were positive correlations (P<0.05) between IGF-I, insulin, glucose and cholesterol, and a negative correlation (P<0.05) between IGF-I and urea. There were also positive correlation (P<0.05) between insulin and glucose and positive correlation (P<0.05) between glucose and cholesterol. There was a negative correlation (P<0.05) of the urea with cholesterol, progesterone and protein. Progesterone also showed a positive correlation (P<0.05) with the protein.

Keywords

• Hormones; Metabolites; Restriction; Refeeding; Cattle.