Comparison of two oestrus synchronisation protocols administered to dairy cows during routine reproduction services
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
L Viora, M Denwood, K Ellis, M Mihm Carmichael, T Geraghty
Progesterone-based oestrus synchronisation protocols are frequently used for treatment of cows presented for examination during routine reproduction management service. This study aimed to evaluate the effect of the addition of gonadotrophin-releasing hormone (GnRH) at the start of a progesterone-based oestrus synchronisation protocol for cows presented for examination during routine veterinary service on a commercial dairy farm over 10 months. Overall 139 animals were retained in the study, of which 78 received a standard progesterone-based treatment (STD) and 61 received the same treatment but with the addition of GnRH on day 0 (STD+). Cows were submitted for artificial insemination following observation of behavioural oestrus. Cow and service specific data were used to create two mixed effects generalised linear models to analyse the effect of treatment group on submission rate (SR) and conception rate (CR). In the final SR model lameness had a significant negative association (p=0.01) and STD+ had a non-significant positive association (p=0.12) with submission. In the final CR model only presence of a new CL at day 7 had a significant positive association (p=0.04) while previous reproductive disease had a non-significant positive association (p=0.83) with conception. These results highlight the difficulties in assessing the real effects of altering reproductive protocols on individual farms when other important explanatory variables are considered.
|Status||Udgivet - jan. 2015|