124 The Effect of Water Restriction at Weaning on Hair Sheep Ewes and Lambs in the Tropics.

This study was designed to evaluate the effect of water restriction at weaning on ewe and lamb traits. Multiparous St. Croix White hair sheep ewes (4.7 y of age) were assigned to treatment based on weaning date and number of lambs. Lambs were weaned at 120 d of age. Treatments consisted of ewes having access to water (WET) or no access to water (DRY) during weaning. On d 1 DRY ewes (n = 10) and lambs (n = 14) were put in a pen with shade but no feed or water and WET ewes (n = 10) and lambs (n = 16) were put in individual pens with shade and water. On d 2 all lambs were removed from ewes and put in a pen with feed, hay and water. The DRY ewes remained in a pen without feed or water and WET ewes remained in the individual pens with water. On d 3 ewes were returned to pasture. On d 1, 2, and 3 ewes and lambs were weighed and jugular blood samples were collected to measure packed cell volume (PCV). Udder volume (UDRVOL) was determined each day by measuring udder longitudinal and lateral semicircumferences with a flexible tape. Daily water consumption of WET ewes was measured by providing each ewe with 6 L of water each morning and then measuring the remaining water the following morning. Data was analyzed using SAS (9.4) with treatment and day as main effects. Day and treatment had no effect (P > 0.10) on ewe or lamb weight. Ewe PCV was greater (P < 0.03) in WET than in DRY ewes (30.6 ± 0.6 vs. 28.8 ± 0.6 %, respectively) but there was no difference between days (P > 0.10). Lamb PCV was not different between WET and DRY or days (P > 0.10). The UDRVOL of DRY ewes was lower than WET ewes (676 ± 35 vs. 789 ± 35 cm3, respectively). The UDRVOL was lower (P < 0.03) on d 2 than on d 1 or 3 (641 ± 43 vs. 774 ± 43 vs. 785 ± 43 cm3, respectively). Water consumption was not different (P > 0.10) between d 1 and 2 (2,057 ± 536 vs. 1,244 ± 547 mL, respectively). These data show that hair sheep in the tropics do not exhibit signs of dehydration from water deprivation during a 48-h weaning process.