The onset of oestrus in sheep can be manipulated in the last few weeks of anoestrus via several techniques (Martin, 2004). Producers use these techniques to manage for an earlier lambing time frame and consequently allow lambs to be marketed earlier in the year. The aim of the study was to see if the sponge technique compromised the performance of the ewes and lambs compared to the use of teaser rams. The key performance indicators of lambing timings; number of lambs per ewe and individual lamb weights were assessed between the two different techniques.
Batten, S., Watson, P., & Evans, B. (2016). Techniques to advance oestrus in ewes – a comparative study between the use of progestagen sponges and the ‘ram effect’. In Advances in Animal Biosciences (Vol. 7). Cambridge University Press. https://doi.org/10.1017/S2040470016000042