title: Lack of effect of transrectal ultrasonography with restraint on lambing rate and prolificacy in ewes.
abstract: The objective was to determine if transrectal ultrasonography for determination of pregnancy in restrained ewes increases embryonic/fetal death or loss of pregnancy. Ten flocks (N=873 ewes) bred in either the estrous or anestrous season were randomized, into control (C) or examined (E) groups within flock. Examined ewes were placed in a tilting squeeze chute and scanned by one of three operators for pregnancy by transrectal ultrasonography once between Days 25 and 100 post-breeding. Control ewes were not subjected to handling in the squeeze chute or pregnancy diagnosis. Two operators counted embryos in E ewes in six flocks. There were no differences between E and C ewes in percent ewes lambing or lambing rate on a per flock basis. Prolificacy per flock was greater in E ewes (P=0.05; 1.53 versus 1.60, C and E, respectively) than in C ewes. Eighty-five percent of exposed ewes lambed in the estrous season, while only 62% of ewes lambed in the anestrous season (P=0.05). Overall prolificacy did not differ with season (1.60 versus 1.53), and there was no season by treatment interaction for any variable tested. Losses averaged 0.02 per E ewe exposed in the estrous season and 0.20 in the anestrous season (P<0.05). Examined ewes in this study had similar pregnancy and lambing rates to C ewes in the same flocks and prolificacy was slightly greater. Based on these data, the combination of transrectal ultrasonography with restraint is safe for pregnancy diagnosis in ewes.
authors.affiliation: Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26505-6108, USA.
authors.forename: A K
authors.initials: AK
authors.lastname: Wurst
authors.forename: A B
authors.initials: AB
authors.lastname: Dixon
authors.forename: E K
authors.initials: EK
authors.lastname: Inskeep
mesh_terms: D000818:Animals; D001723:Birth Rate; D005260:Female; D005313:Fetal Death / Q000662:veterinary; D006234:Handling, Psychological; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000662:veterinary; D011258:Pregnancy Tests / Q000379:methods / Q000592:standards / Q000662:veterinary*; D011897:Random Allocation; D012756:Sheep; D016216:Ultrasonography, Prenatal / Q000592:standards / Q000662:veterinary*