Energy requirements of early‐weaned Dorper cross‐bred female lambs

Abstract

The net and metabolizable energy (NE and ME) requirements of Dorper cross-bred female lambs with BWs of 20-35 kg were assessed in a comparative slaughter trial. Thirty-five Dorper × thin-tailed Han cross-bred female lambs weaned at ~50 days of age (20.3 ± 2.15 kg BW) were used. Seven randomly selected lambs were slaughtered at the start of the trial (baseline group). An intermediate group consisting of seven randomly selected lambs fed ad libitum was slaughtered when the lambs reached an average BW of 28.5 kg. The remaining 21 lambs were allotted randomly to three levels of dry matter intake: ad libitum or restricted to 70% or 40% of the ad libitum intake. All the lambs were slaughtered when the sheep fed ad libitum reached a BW of 35 kg. Total body energy, nitrogen, fat, ash and moisture content were determined. In a digestibility trial, an additional 15 Dorper × thin-tailed Han cross-bred female lambs (28.7 ± 1.75 kg BW) were housed in metabolism cages and used in a completely randomized design experiment to evaluate the ME value of the diet at the three feed intake levels. The maintenance requirements for NE and ME were 245.5 and 380.3 kJ/kg metabolic shrunk body weight (SBW ) respectively. The partial efficiency of energy use for maintenance was 0.645. The NE requirements for growth ranged from 1.18 to 5.18 MJ/d for the lambs gaining 100-350 g/d from 20 to 35 kg BW. Partial efficiency of ME for growth was 0.44. In conclusion, the current study suggests that the NE requirement for maintenance and growth of Dorper early-weaned cross-bred female lambs is lower than the current AFRC and NRC recommendations.

Prediction of methane emission from sheep based on data measured in vivo from open-circuit respiratory studies

“…The dataset used in the present study was obtained from 159 lambs in seven energy metabolism studies undertaken as part of the National Technology Program for the Meat Sheep Industry of China from 2010 to 2015 [17–20,25–27]. The animals were offered pelleted diet in all studies with concentrate:forage ratio ranging from 12:88 to 92:8.…”

“…With the introduction of Dorper sheep from Australia in 2001 [16], Dorper sheep×thin-tailed Han crossbred sheep has become a predominant breed for meat-producing in China. In recent years, the nutrient requirements of Dorper×thin-tailed Han crossbred sheep in terms of energy [17–20], protein [21–23], and minerals [24] have been extensively studied and reported. Based on those conditions, dataset used in the current study to provide basic CH 4 emission parameters were obtained from the same breed (Dorper×thin-tailed Han), feeding conditions (confined indoors), and feeding regime (pelleted diet), which largely mirrors the current characteristics of sheep production system in China.…”

Feed intake, digestibility and energy partitioning in beef cattle fed diets with cassava pulp instead of rice straw

“…Beef cattle feeding systems that do not meet the energy requirements of the animals may result in the failure of livestock to meet performance expectations [ 1 , 2 ]. The major reasons for low productivity in tropical developing countries are the genetic potential of the animals, the available feeds and the feeding systems, which depend on rice straw or other low-quality crop by-products and thus limit feed intake and digestion, productivity and environmental sustainability [ 3 – 6 ].…”

Net protein and metabolizable protein requirements for maintenance and growth of early-weaned Dorper crossbred male lambs

“…In the intensive livestock industry, protein is commonly the most expensive feed component and therefore, it is necessary to have a precise understanding of protein requirement of livestock not only to ensure farm profitability, but also to help reduce nitrogen (N) emission to the environments [ 1 ]. Modern feeding systems, such as Agricultural and Food Research Council (AFRC) [ 2 ], Commonwealth Scientific and Industrial Research Organisation (CSIRO) [ 3 ], and National Research Council (NRC) [ 4 ], have reported protein and other nutrient requirements of sheep, which are widely adopted for diet formulation in the world.…”