Re-insertion of a progesterone-containing intravaginal device to synchronise returns to oestrus in dairy heifers

Authors: Pfeiffer DU, Hanlon DW, Williamson NB, Steffert IJ, Wichtel JJ
Publication: New Zealand Veterinary Journal, Volume 45, Issue 1, pp 15-18, Feb 1997
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Reproduction - hormones, Treatment/therapy, Animal remedies/veterinary medicines, Endocrine/autocrine/paracrine, Reproduction, Oestrus/oestrous, Husbandry/husbandry procedures, Reproduction - female, Anatomy
Article class: Scientific Article

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Abstract: Recommendations for oestrus synchronisation of dairy heifers using progesterone-containing intravaginal devices suggest re-insertion of used devices 16 days after first insemination for a period of 5 days to allow a second opportunity for artificial insemination. Controlled studies on the effectiveness of re-using intravaginal devices to synchronise returns to oestrus in non-pregnant dairy heifers are lacking. A clinical trial was conducted involving 750 Friesian heifers in 13 herds. Afier an initial synchronisation programme, the used intravaginal devices were re-inserted 14 or 16 days after first insemination into half of the heifers in each herd for a period of 5 days. After the first synchronisation programme, 47.5% of heifers remained non-pregnant.
Re-insertion of used intravaginal devices for 5 days significantly increased the number of non-pregnant heifers detected in oestrus and inseminated by 48 hours atler device removal compared to heifers in which devices were not re-inserted (45.2% v. 27.3%, p < 0.05, in herds where intravaginal devices were re-inserted on day 14; 48.8% v. 13.6%, p < 0.05, in herds where intravaginal devices were re-inserted on day 16). Re-insertion at 14 or 16 days afler first insemination was equally effective in increasing visible returns to service. However, the number of non-pregnant heifers synchronised for a second round of artiticial insemination was less than expected. Conception rate to the re-synchronised oestrus was unaffected by the treatment. It is concluded that the additional procedures of CIDR re-insertion, removal, tailpainting and insemination involved in there-synchrony programme, and the relatively low in-calf rate to the re-synchronised round of insemination, reduced the potential benefits of re-synchronisation.

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