Farm Table says:
What is the problem?
Early weaning is a strategy employed in lamb finishing. A number of different strategies exist for early weaning, including creep feeding. The aim of this study was to evaluate the performance, carcass traits and the finishing costs of Suffolk lambs in systems with early weaning. The study looks at concentrate supplementation on pasture or in confinement from weaning to slaughter.
What did the research involve?
The performance, carcass traits and finishing costs of Suffolk lambs were evaluated in three systems:
- lambs weaned with 22 kg of body weight (BW) and supplemented with concentrate on pasture until slaughter. Kept with ewes on annual ryegrass and creep fed on protein-energy concentrate of 1.85% of BW in DM/day.
- lambs weaned with 22 kg BW and fed in feedlot until slaughter. Lambs were fed diet containing 600 g/kg DM of protein-energy concentrate and 400 g/kg DM of corn silage.
- lambs maintained in controlled nursing after 22 kg BW and creep fed in feedlot until slaughter. Ewes were separated from lambs every day for 6 hours and lambs were fed diet containing 400 g/kg DM of protein-energy concentrate and 600 g/kg DM of corn silage.
The study took place in Brazil. 18 non-castrated Suffolk male lambs were distributed uniformly across the three systems.
Average daily gain (ADG) was 224 g/d for lambs weaned and supplemented with concentrate on pasture, 386 g/d for lambs weaned in the feedlot and 481 g/d for lambs under controlled nursing.
What were the key findings?
- Empty body weight and visceral fat deposition were highest in lambs from feedlot systems.
- Carcass weights and carcass yields were highest for lambs in controlled nursing.
- Finishing total costs were highest in controlled nursing and lowest in the system with weaning in the feedlot.
- High concentrate diet associated with controlled nursing in feedlot allowed lambs to reach the growth potential and carcasses with higher weights, higher yields, and higher fat content.
- After weaning, lambs in feedlot fed with high concentrate diet had higher weight gain than lambs supplemented with concentrate on pasture.
- Carcasses produced under these two systems presented the same characteristics. The system with weaning in feedlot showed the lowest cost per kg carcass.
- Cost of feeding the lambs was highest in the system with weaning in confinement and lowest in the system with weaning on pasture.
The combination of high concentrate diet with the practice of controlled suckling in feedlot allows the lambs to express their potential for weight gain, reaching the slaughter weight in shorter time and producing heavier and high-fat carcasses.
The finishing of weaned lambs with concentrate supplementation on pasture or with high concentrate diet in feedlot results in the production of similar carcasses. However, the finishing on feedlot determines higher weight gain for the lambs, reducing the time to reach slaughter weight.
The costs of labour and technical assistance and those related to lambs feeding, the finishing period and the final weight of the carcasses have a strong influence on the total finishing cost. The system with weaning in feedlot showed the greatest balance among these factors, with the lowest cost per kg/carcass produced.