The effect of water restriction on growth performance, water consuming pattern, digestibility, and slaughter parameters of Lori-Bakhtiari and Lori-Bakhtiari×Romanov lambs

The aim of this study was to investigate the growth performance, water consuming pattern, digestibility, and carcass traits of Lori-Bakhtiari (LORI) and Romanov-Lori-Bakhtiari (CROSSbred) lambs under water restriction conditions. Twenty lambs (10 heads per genotype) with an average weight of 31±2.5 and an age of 8±2 months were used in four treatments with 5 replications in each in a completely randomized design with 2×2 factorial. Water-restricted (WR) lambs had free access to water for only one hour a day. All lambs were slaughtered after six weeks. Feed intake, daily weight gain and final weight were not affected by genotype and access to water, while water intake (p=0.001) and water to feed ratio (p=0.02) were significantly dropped with water restriction. Water-restricted lambs consumed almost 90 percent of their water intake in the first five minutes. Nutrients digestibility was not affected by the treatments, but the amount of fecal dry matter was significantly high in water restricted groups (p=0.03). Carcass weight and yield were not affected by the treatments, but the percentage and weight of tails in the CROSSbred lambs were lower (p≤0.0001), but part of this decrease was compensated by higher fat thickness (p=0.05) and visceral fat (p=0.03).  The overall results of this study showed that genotype and water restriction did not significantly affect growth performance, so CROSSbred lambs can be used in water restricted area.