Preliminary Data Comparing Embryo Transfer Efficiency of Simmental Half-Sister Donors

Normal vs 14/20 Centric Fusion Carrier

Authors

  • T. Q. Zhang College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108
  • L. C. Buoen College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108
  • M. Davies DeerTrail, Colorado 80105 U.S.A.
  • A. F. Weber College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108
  • G. R. Ruth College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108

DOI:

https://doi.org/10.21423/aabppro19926569

Keywords:

reproductive potential, calving-to-conception interval, cytogenetic anomaly, insemination index, 1/29 centric fusion, CF, Robertsonian translocation

Abstract

The effect of the 1/29 centric fusion (CF, Robertsonian translocation) anomaly is quite well known. Swedish researchers1 first reported a 7% reduction in fertility in Swedish Red and White cattle based on non-return rates of cows bred to heterozygous positive (carrier) bulls. A study2 of the reproductive efficiency of beef cattle carrying this cytogenetic anomaly vs. that of normal (noncarrier) beef animals showed that the carrier bulls had a 0.52 greater insemination/pregnancy index. carrier daughters of affected bulls had a calving-to-conception interval that was 18. 5 days longer than that of daughters of normal bulls. Similar results were obtained in a study in Brazil3. Schmutz et al4 studied the chromosomes of 39 seven day-old embryos collected from nine 1/ 29 CF carrier cows and 38 cows with normal karyotypes bred to normal and 1/29 CF carrier bulls. in each case the matings were between a normal and 1/29 CF carrier bulls. The 39 embryos were from 374 fertilized ova obtained from 86 successful collections where all chromosomes of isolated embryo cells could be identified. They found that 8 of the 39 embryos (20.5%) would have died in utero because their cells contained unbalanced karyotypes (unequal, lethal distribution of chromosomes, i.e., monosomies and trisomies), It was concluded that the major loss in reproductive potential of the 1/29 CF carrier cows or bulls appeared to be due to early embryonic death rather than fertilization failure. However, there are no published data regarding the effect of CF translocations on bovine embryo transfer (ET) efficiency.

Since the 14/20 CF was found in the Simmental breed in the US two years ago, our laboratory has received more than 400 blood samples from concerned Simmental cattle breeders. Among these animals one of a pair of half-sister donor cows for ET was diagnosed a 14/20 CF carrier and the other a non-carrier. This paper presents preliminary data comparing embryo transfer efficiency of the two Simmental half-sister donors: Normal vs 14/20 CF carrier.

Cover image of the Third Volume of the 25th Conference Proceedings: An earl-morning photo of farmland. A small farm is nestled among rolling hills, fields stretching across a curving road that disappears between dark green trees. The barn is a cheery red color with a tin roof. Beneath the photo is the a statement of the conference's theme in white italics: Challenges of the Bovine Industry in the Twenty-First Century. Deep red background.

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Published

1992-08-31

Issue

1992: Volume 3

Section

Genetics and Theriogenology