Objective:

To determine some indicators of the gas-energy metabolism of fasting Pelibuey sheep, subject to grazing.

Materials and Methods:

The research was conducted at the Jorge Dimitrov Research Institute, in the Granma province, Cuba. Seventy-five sheep were used, grazing during the growth-fattening stage, at a rate of 25 animals of the Bermejo, Blanco and Patrón invertido genotypes, respectively. The animals were subject to inedia for up to 96 hours, to evaluate the respiratory quotient and heat production every 24 hours. The respiratory rate, heart rate, and rectal temperature were measured.

Results:

The respiratory rate showed an average of 63 breaths per minute, influenced by climate indicators that affected the welfare zone of grazing sheep. The average heart rate was 75 beats per minute, a value that was considered adequate for sheep under grazing conditions in a tropical climate. Basal metabolism was reached at 96 hours of fasting. Differences were found in the respiratory quotient for Bermejo, Blanco and Patrón invertido (0,67; 0,61; 0,64, respectively). Heat production (KJ/kg w0,75/day) also showed differences among genotypes (142,3; 129,4 and 139,4 for Bermejo, Blanco and Patrón invertido, respectively).

Conclusions:

The Pelibuey sheep, subject to fasting, reached basal metabolism 96 hours after stopping feeding, period in which they reached respiratory quotients typical of fat degradation.

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