Performance and carcass characteristics of lambs fed a solution of cheese whey during feedlot and pre-slaughter lairage

ABSTRACT The objective of this study was to evaluate performance and carcass and meat characteristics of lambs fed a solution of cheese whey plus water (100 g kg−1 dry matter) (CW) during feedlot and pre-slaughter lairage. Data were analyzed as a 2 × 2 factorial (place – feedlot and slaughterhouse, food – water or CW). We evaluated the following treatments (feedlot/slaughterhouse): CW/CW, CW/water, water/CW, and control (water/water). The lambs were given a balanced diet for 70 days in the feedlot. Slaughter started 12 h after the animals arrived at the slaughterhouse. Dry matter intake, gain-to-feed ratio, average daily gain, and body weight of lambs fed CW were similar to those of control lambs. The water/CW group consumed less of this solution than the CW/CW group in the slaughterhouse. The CW supplied as a pre-slaughter supplement reduces the drip losses of lamb carcasses provided that the animals also consume it during the feedlot period. The other carcass characteristics (carcass weight, pH, subcutaneous fat thickness, and ribeye area) were similar among treatments. The meat characteristics (color, water holding capacity, cooking losses, and shear force) were similar among treatments. Whey cheese added to water can be used as an ingredient of the diet for lambs and as pre-slaughter supplement, since it does not change performance and improves carcass characteristics.

摘要
本研究旨在评估在育肥期及屠宰前待宰圈饲喂干物质含量为100 g·kg⁻¹的干酪乳清水溶液（Cheese Whey，CW）的羔羊，其生长性能、胴体及肉品质特性。本试验采用2×2双因素析因设计，试验因素分别为饲喂地点（育肥场、屠宰场）与日粮类型（清水或CW乳清水溶液）。试验设置四组处理（育肥场饲喂方案/屠宰场饲喂方案）：CW/CW组、CW/清水组、清水/CW组及对照组（清水/清水组）。试验羔羊在育肥场饲喂全价平衡日粮，为期70天，羔羊抵达屠宰场后12小时开始屠宰。
饲喂CW乳清水溶液的羔羊，其干物质采食量、料重比、平均日增重及体重均与对照组羔羊无显著差异。屠宰场阶段，清水/CW组羔羊对该溶液的采食量低于CW/CW组。
若羔羊在育肥期也饲喂CW乳清水溶液，则作为屠宰前补饲剂的CW可降低羔羊胴体的滴水损失。其余胴体性状（胴体重、pH值、皮下脂肪厚度及眼肌面积）在各组处理间均无显著差异。肉品质性状（色泽、持水力、烹饪损失及剪切力）在各组处理间亦无显著差异。
将干酪乳清加水调配后，可作为羔羊日粮组分及屠宰前补饲剂使用，因其不会影响羔羊生长性能，且可改善胴体性状。