Production evaluation of Booroola fecundity (FecB) gene introgressed Avishaan sheep in semi-arid tropics of India

The breeding goal for evolving of Avishaan sheep was to develop a sheep strain with high prolificacy, more live weight, better survival and mothering ability. The introgression of FecB gene from the small sized ‘Garole’ sheep breed of Sunderban region in eastern India into the non-prolific monotocous sheep Malpura in the semi-arid region of Rajasthan, was attempted, followed by back-crossing with Malpura ewes. The resulted genotype was used as male line and crossed with heavy weight Patanwadi sheep, known for its higher milk yield. The obtained triple breed cross sheep was further selected using marker assisted selection using FecB gene and higher growth for obtaining three breed cross ‘Avishaan’ sheep that fulfils the breeding goal. The average live weight for Avishaan lambs at birth, 3, 6 and 12 months were 2.61 ± 0.03, 14.92 ± 0.20, 23.48 ± 0.31 and 31.48 ± 0.46 kg, respectively. The sheep strain is highly prolific and has shown improvement in multiple births from 22.2% to 74.4% over a period of nine years. High ewe productivity efficiency (EPE) of 22.19 kg for litter weight at 3-month was observed in Avishaan ewes due to higher prolificacy, lower lamb mortality and availability of sufficient milk from the dam. Avishaan excelled local monotocus Malpura sheep by 45% for EPE. The genetic analysis revealed that the heritability (h2) for live weight traits was moderate in Avishaan sheep. The h2 for 6-month live weight was 0.36 ± 0.13, indicating scope of further selection for growth in lambs. The development of the Avishaan strain was a successful venture, however, further efforts are required to improve the growth potential for harvesting more live weight per unit of sheep.