ARS | Publication request: Ultrasound and phenotypic measures of the reproductive tract of prepubertal gilts selected for increased uterine capacity

Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: November 8, 2011
Publication Date: March 1, 2012
Citation: Lents, C.A., Cushman, R.A., Freking, B.A. 2012. Ultrasound and phenotypic measures of the reproductive tract of prepubertal gilts selected for increased uterine capacity [abstract]. Journal of Animal Science. 90 (Supplement 2):118 (Abstract #299P).

Technical Abstract: Direct selection for uterine capacity (UC) increases litter size without altering ovulation rate. A method to estimate UC in developing gilts would be beneficial for commercial selection strategies. We tested the hypothesis that selection for UC alters phenotypic characteristics of the reproductive tract of prepubertal gilts and that these changes could be estimated in live animals using transrectal ultrasound (TRU). Gilts from a line selected for UC or from a randomly selected control line (CO) were submitted for TRU at 130, 150, or 170 d of age and sacrificed 24 h later (n = 10 gilts/line per age). Diameter of the uterine horn was measured (2 to 4 measurements per animal) at TRU. At sacrifice, measurements of each ovary (height, width, length, weight, and number of visible follicles > 1 mm) and uterine horn (weight, length, diameter, and endometrial diameter) were taken. There was no line x age interaction for any of the traits. All ovarian traits increased (P < 0.03) with age. Weight and length of the uterine horn was not different at 130 or 150 d but was increased (P < 0.01) at 170 d of age. Diameter of the uterine horn tended (P = 0.06) to be increased at 170 d compared with 130 or 150 d, but age did not affect (P = 0.38) endometrial diameter. Ovarian weight and width were increased (P < 0.01) and ovarian length and height tended (P = 0.07) to be greater for UC than CO gilts, but the number of visible follicles did not differ. The UC gilts had increased (P < 0.02) weight of uterine horns, which tended (P = 0.09) to be longer than in the CO gilts. Diameters of the uterine horn and the endometrium were greater (P < 0.01) for UC gilts than for CO gilts. Uterine horn diameter measured with TRU was not affected by age or line and was not correlated with any of the traits. Selection for increased UC results in larger ovaries and uterine horns, but TRU is not sensitive enough for estimating these traits in gilts of the age studied. USDA is an equal opportunity provider and employer.