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Effects of deep-horn AI on fertilization and embryo production in superovulated cows and heifers P.

D. Carvalho a,1 , A.H. Souza a,1 , R. Sartori a,b , K.S. Hackbart a , A.R. Dresch a , L.M. Vieira a,c , P.S. Baruselli c , J.N. Guenther a , P.M. Fricke a , R.D. Shaver a , M.C. Wiltbank a,* a Department of Dairy Science, University of Wisconsin-Madison, Wisconsin, USA b University of S?o Paulo, Luiz de Queiroz School of Agriculture, Piracicaba, S?o Paulo, Brazil c Department of Animal Reproduction, University of S?o Paulo, S?o Paulo, Brazil a r t i c l e i n f o Article history: Received

2 July

2013 Received in revised form

10 August

2013 Accepted

10 August

2013 Keywords: Superovulation Arti?cial insemination Deep uterine horn Subclinical endometritis a b s t r a c t The primary objective of this study was to determine the effect of site of semen deposition on fertilization rate and embryo quality in superovulated cows. The hypothesis was that deposition of semen into the uterine horns would increase the fertilization rate compared with deposition of semen into the uterine body. The secondary objective was to evaluate the effect of uterine environment on fertilization rate and embryo quality. It was hy- pothesized that subclinical endometritis at the onset of superstimulation would decrease the fertilization rates and embryo quality. In experiment 1,

17 superovulated heifers were randomly assigned to receive arti?cial insemination (AI) into the uterine body or uterine horns. The total number of fertilized structures and fertilization rate from superovulated heifers was increased (P ? 0.04 and P ? 0.02, respectively) when semen was deposited into the uterine horns compared with the uterine body. Other embryo characteristics did not differ based on the site of semen deposition. In experiment 2,

14 lactating dairy cows were superovulated twice and were randomly assigned to receive AI into the uterine body or deep into the uterine horns using a crossover design. Neither fertilization rate nor any other embryo characteristics were improved when semen was placed deep into the uterine horns compared with the uterine body. In experiment 3,

72 superovulated lactating dairy cows were randomly assigned to receive AI into the uterine body or uterine horns. Before initiation of superstimulatory treatments, an endometrial cytology sample was collected from each cow. Ova/embryos were collected by a nonsurgical technique at

70 ?

3 days in milk. Similar to experiment 2, neither fertilization rate nor any other embryo character- istics differed based on the site of semen deposition in experiment 3. The percentage of cows with subclinical endometritis did not differ between treatments. Interestingly, there was a tendency (P ? 0.09) for a reduction in embryo recovery rate and a reduction (P ? 0.01) in the fertilization rate for cows with subclinical endometritis. In conclusion, depo- sition of semen into the uterine horns rather than into the uterine body did not improve the fertilization rate or embryo quality in superovulated cows. Subclinical endometritis decreased the fertilization rate in superovulated cows. ?

2013 Elsevier Inc. All rights reserved. 1. Introduction Successful fertilization in vivo depends on coordinated transport of viable male and female gametes into the oviduct [1C3]. Although arti?cial insemination (AI) with frozen semen has facilitated dramatic genetic progress * Corresponding author. Tel.: ?608

263 9413;

fax: ?608

263 9412. E-mail address: [email protected] (M.C. Wiltbank).