Return to cyclical activity in ewes with energy and protein restriction during lactation period

Abstract

Inadequate ingestion of nutrients in quality and quantities is common cause of infertility in ewe and mechanisms involved between nutrition and reproduction is changeable. The aim of this work was to evaluate the energy or protein restriction during lactation in ewe on return of reproductive cyclic activity. Twenty one females in post-partum was divided randomly in 3 treatments: control treatment (CT, diet supply the requirements for maintenance and lactation), caloric restriction (CRT, supplied ½ of the diet of the CT), protein restriction (PRT, supplied 1/3 of the protein of the CT). Trans-rectal ultrasound was performed to ovary evaluation weekly and the body weight were measured biweekly. Effect of treatment on number (P<0.0001) and diameter (P<0.0001) of follicle was observed. PRT (3.32 ± 1.79; 1.45 ± 0.15) was lesser CRT (4.12 ± 1.98 ; 1.55 ± 0.09) and CT (4.94±2.01; 3.32 ± 0.22). Interaction between treatment and week in follicles lesser or equal 3 mm (P=0,0007) and greater of 3 mm (P<0,0001) added the presence of corpus luteum (P=0.0319) in the CT demonstrated effect of energy or protein restriction in the cyclic pattens of nursing sheep. On the basis of the results conclude that the nutritional restriction affects the return of the cyclical activity in the post-partum of sheep.