Comparison of weigh-suckle-weigh and machine milking for measuring ewe milk production

Thirteen crossbred ewes were used to compare weigh-suckle-weigh (WSW) and m achine milking (MM) methods for determining milk production of ewes that we re rearing single or twin lambs. At parturition, ewes were 13 mo of age and produced six single lambs and seven pairs of twin lambs. Milk production e stimates were initiated on d 6 of lactation and a 3-d rotation of the two t echniques was implemented. On d 6, milk production was measured using WSW; on d 7, MM was used. No measurement was made on d 8. The 3-d rotation was r epeated 20 times throughout a 63-d lactation, resulting in 20 point estimat es of milk production for each method of measurement for each ewe. The WSW procedure consisted of a 3-h period in which lambs were withheld from suckl ing their dams. This was followed by a suckling period, a second 3-h withho lding period, and a second suckling period. Differences in pre- and postsuc kling lamb weights of the second suckling period were defined as milk consu mption and, indirectly, 3-h milk production. The MM procedure included an a dministration of 10 IU of oxytocin (i.v.), followed by evacuation of the ud der with a machine using commercially available sheep milking equipment, an d the milk was discarded. Lambs were withheld from suckling the ewes for a 3-h period, followed by a repetition of the oxytocin and machine milking pr ocedures. Milk from the second milking was weighed. Milk production estimat es determined using the WSW and MM techniques were similar (P = .42). Avera ge 3-h milk production was 340 and 351 g for WSW and MM, respectively. Mach ine milking provides a reliable tool in evaluating the milk-producing abili ty of ewes that are rearing single or twin lambs.