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Báo cáo khoa học: "Reproductive performance of Norwegian cattle from 1985 to 2005: trends and seasonality"

Tuyển tập các báo cáo nghiên cứu về bệnh học thý y được đăng trên tạp chí Acta Veterinaria Scandinavica cung cấp cho các bạn kiến thức về bệnh thú y đề tài: Reproductive performance of Norwegian cattle from 1985 to 2005: trends and seasonality. | Acta Veterinaria Scandinavica BioMed Central Research Open Access Reproductive performance of Norwegian cattle from 1985 to 2005 trends and seasonality Arne Ola Refsdal Address Geno AI and Breeding Hamar Norway Email Arne Ola Refsdal - arne.ola.refsdal@geno.no Corresponding author Published 13 February 2007 Received 23 October 2006 . . r r . nftft-r An I- . Ift I I ft 1 -71-1 ft I A-t ft I- Accepted 13 February 2007 Acta Veterinaria Scandinavian 2007 49 5 doi l0.ll86 1751-0147-49-5 This article is available from http www.actavetscand.cOm content 49 1 5 2007 Refsdal licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http creativecommons.org licenses by 2.0 which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Declining reproductive performance is a serious breeding concern in many countries. To reveal the situation in Norwegian cattle trends in reproductive performance were studied using insemination reports from 1985 to 2005 and data based on herd recording files from 1989 to 2005. The total number of first services was 469.765 in 1985 declining to 335.712 in 2005. The number of recorded herds and animals declined from 21.588 to 14.718 and 360.289 to 309.452 from 1989 to 2005 respectively. Sixty days non-return rate after single inseminations NR60 increased from 68.1 in 1985 to 72.7 in 2005 p 0.001 and the number of services per inseminated animal NIA decreased from 1.8 to 1.6 p 0.001 from 1985 to 2005. However return rates 0-3 days post insemination R.R.0-3 increased from 6 to 12 in the same period p 0.001 . NR60 was higher and the RR0-3 was lower in the summer season compared to the winter season during the whole period. A fertility index FS has been calculated from the herd recording files each year from 1989 to 2005. The average FS-index did not show a significant trend and the calving interval was also .