GENOTYPE-ENVIRONMENT INTERACTION IN PERFORMANCE TESTS FOR SHEEP IN CONFINEMENT AND ON PASTURE

Abstract

This study aimed to verify the existence of genotype–environment interaction and performance of Santa Inês sheep in confinement and on pasture.  Eighty-two Santa Ines lambs at 75-135 days of age were used. The adaptation period lasted 22 days. Animals were from five different farms, 30 animals were kept on pasture for 112 days and 52 animals were kept in confinement for 85 days. Animals were evaluated on weight gain (WG), body length (BL), thoracic perimeter (TP), hip height (HH), breast height (BH), rib-eye area (REA) and fat thickness (FD) using ultrasound, and scrotal circumference (SC), worm load (FEC) and body condition score (CS). An index (FI) was calculated using the measures taken.  The SAS® software was used for statistical analysis. There was a statistical difference among animals for type of test (confinement or pasture) for WG, REA, FD, SP as well as FI. Measures for animals in confinement were generally higher than for animals on pasture, except for FI and SP. The age at the start of the test did not influence the expression of characteristics. There was no evidence found of a genotype–environment interaction for Santa Ines breed animals in weight gain on pasture and in confinement for the evaluated characteristics.

KEYWORDS: fat thickness; index; rib eye area; subjective evaluation; ultrasound.