ABSTRACT

Background and Aim: Intensive sheep production systems in tropical regions frequently depend on concentrate-based diets to sustain rapid growth and carcass quality; however, increasing grain costs have stimulated interest in incorporating locally available tropical forages as partial substitutes. This study evaluated the effects of including Maralfalfa (Pennisetum sp.), Mombaza (Megathyrsus maximus), or CT-115 (Pennisetum purpureum) in concentrate-based diets on nutrient digestibility, growth performance, carcass traits, and meat quality of hair sheep raised under intensive tropical conditions. 

Materials and Methods: Two complementary experiments were conducted at the Mocochá Experimental Field of the National Institute of Forestry, Agricultural, and Livestock Research, Yucatán, México. Apparent digestibility was evaluated in 16 Katahdin × Pelibuey rams (27.2 ± 4.3 kg body weight) assigned to four dietary treatments: concentrate feed alone or concentrate feed supplemented with 30% Maralfalfa, Mombaza, or CT-115 on a dry matter basis. Growth performance, carcass characteristics, and meat quality were assessed in 36 Katahdin × Pelibuey lambs (18.0 ± 3.3 kg body weight) fed the same diets for 84 days. Measurements included dry matter intake, apparent digestibility, average daily gain, slaughter live weight, carcass yield, Longissimus dorsi muscle area, pH, drip loss, and proximate composition of meat. Data were analyzed using general linear and mixed-effects models. 

Results: Concentrate-fed lambs showed the greatest apparent digestibility of dry matter, crude protein, neutral detergent fiber, and acid detergent fiber, whereas CT-115 reduced nutrient digestibility, particularly fiber utilization (p < 0.01). Nevertheless, forage inclusion significantly increased total dry matter intake compared with concentrate feed alone (p ≤ 0.01). Average daily gain, slaughter live weight, hot carcass weight, carcass yield, backfat thickness, and Longissimus dorsi muscle area were not significantly affected by dietary treatment (p > 0.05). Meat pH, temperature, and drip loss remained within normal physiological ranges across all diets. Lambs fed concentrate feed alone exhibited greater intramuscular fat deposition, whereas forage-fed groups showed higher moisture content (p < 0.05). 

Conclusion: The inclusion of up to 30% Maralfalfa, Mombaza, or CT-115 in concentrate-based diets maintained growth performance, carcass characteristics, and meat quality in hair sheep under intensive tropical conditions. Although concentrate-only feeding maximized nutrient digestibility, forage supplementation increased feed intake without compromising productive or carcass responses, supporting the nutritional feasibility of tropical forages as partial concentrate substitutes in sheep production systems. 

Keywords: carcass traits, digestibility, growth performance, hair sheep, intensive feeding, meat quality, tropical forages, tropical sheep production.