Reproductive examination and histopathological findings of somatic cell-cloned holstein friesian cows [Bos taurus] with low reproductive and low lactational performance
2006
Takahashi, M.(Koiwai Noboku Co. Ltd., Shizukuishi, Iwate (Japan)) | Tsuchiya, H. | Ueki, A. | Mita, N. | Kubo, M. | Goryo, M. | Hashizume, T. | Osawa, T.
Two somatic cell-cloned Holstein Friesian cows (Cody 1 and Cody 2) diagnosed as having low reproductive or low lactational performance were examined. Although AI or ET was performed 15 times, Cody 1 became pregnant only twice, ultimately miscarrying. Given these results, the animal was euthanized at the age of 61 months. Cody 2 calved twice with a calving interval of 690 days. In both cows, GnRH analog (fertirelin acetate, 100mu g/head) was injected intramuscularly to test the ability of LH release from the pituitary, and the LH responses were similar to those of the two control cows. Macroscopically, the uterus in Cody 1 was discolored and hypoplastic, and light microscopy disclosed that there were many calcareous deposits on the wall of some uterine arteries as well as an increased number of arteries in the endometrium. In Cody 2, milk composition was normal, whereas milk yields at primiparity (3,897 kg/305days) and secondary parity (6,312 kg/305days) were much lower than those (average 11,015 kg/305days) of the somatic cell-donor cow. These results indicate the possibility that certain somatic cell-cloned cows may have low reproductive performance and low milk production.
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