Synergizing reproductive efficiency and growth performance: A large-scale evaluation of Dorper × Garut crossbreeding...

Sheep farming is a vital component of Indonesia's agricultural economy, where the demand for meat continues to rise. Indigenous Garut sheep are well-adapted to local environments and are known for their high reproductive efficiency, but they have low growth rates. Conversely, Dorper sheep are renowned for their rapid growth and carcass quality, but they exhibit longer lambing intervals under tropical conditions. Crossbreeding offers a strategy to combine the strengths of both breeds. This study aimed to evaluate maternal reproductive performance and pre-weaning growth traits in purebred Dorper, Garut, and Dorper × Garut crossbred sheep under a commercial breeding system in Indonesia.

A retrospective observational study was conducted on 1,744 ewes (1,498 Garut, 209 F1 Dorper × Garut, and 93 Dorper) and 3,248 lambs (2,846 F1 Dorper × Garut, 253 B1 backcrosses, and 149 Dorper) from a commercial enterprise in West Java. Data included lambing interval, litter size, birth weight, weaning weight, pre-weaning mortality, average daily gain (ADG), reproductive index, and productivity index. Statistical analyses employed one-way analysis of variance with Duncan's multiple range test for post hoc comparisons.

F1 Dorper × Garut crossbred ewes demonstrated significantly shorter lambing intervals (206.65 ± 2.75 days) than pure Dorper (265.66 ± 1.14 days), comparable to Garut ewes (209.10 ± 1.08 days). However, Garut ewes had superior litter size (1.77 ± 0.18) relative to both crossbred (1.33 ± 0.04) and Dorper ewes (1.30 ± 0.42). In growth performance, Dorper lambs excelled in birth weight (3.35 ± 0.07 kg), weaning weight (23.93 ± 0.57 kg), and ADG (203.88 ± 4.65 g/day). F1 Dorper × Garut lambs showed significantly higher weaning weight (19.48 ± 0.35 kg) and ADG (165.34 ± 2.95 g/day) compared with Garut lambs (15.36 ± 0.10 kg; 130.47 ± 0.83 g/day).

F1 Dorper × Garut crossbreeding synergizes Garut's reproductive efficiency with Dorper's growth performance, yielding crossbreds well-suited for tropical meat production. While Garut maintains a prolificacy advantage, F1 crossbreds deliver improved pre-weaning growth, supporting their use in commercial fattening programs. Maintaining pure Garut flocks for breeding and employing F1 crossbreds for production may enhance productivity and sustainability in Indonesia. Future research should assess carcass traits, multigenerational crossbreeding, and economic feasibility.