Authors
1
Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan 84156–83111, Iran
2
Animal science, Isfahan University of Technology, Isfahan, Iran.
3
Department of Animal Science, College of Agriculture, Isfahan University of Technology, Isfahan
4
Isfahan University of Technology
5
Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
6
Isfahan Agricultural and Natural Resources Research and Education Center, AREEO, Isfahan, Iran
Abstract
Background and Objective: Most agricultural wastes are rich in carbohydrates, so that in recent years, due to the increase in the price of livestock inputs, the desire to use them has increased, and on the other hand, these materials can play an effective role in improving environmental conditions and developing sustainable agriculture. The aim of this study was to investigate the effects of replacing part of the forage and concentrate diet with green almond hulls on growth performance, nutrient digestibility and blood parameters of feedlot lambs.
Materials and Methods: This experiment was conducted using 24 Afshari feedlot male lambs with an average body weight of 31 ± 3.12 kg (3 to 4 months) in a completely randomized experimental design with three treatments and eight replications. The treatments included a control group (0% green almond hulls), a treatment containing 15% green almond hulls, and a treatment containing 30% green almond hulls. The diets had approximately equal energy and protein content, but neutral detergent fiber decreased linearly with increasing green almond hulls level. The first two weeks were considered for lambs to adapt to the diets, and the lambs were kept in individual pens until they reached a weight of approximately 48.8 kg. During the two weeks of adaptation, 5% of the concentrate portion of the diets was increased daily, so that after 14 days of adaptation, the ratio of forage to concentrate in the lambs was 30 to 70.
Results: Increasing the level of almond hulls feeding increased feed intake linearly (P < 0.01). The final weights of the lambs were the same. Lambs fed 30% green almond hulls had higher growth rates (385 vs. 319 and 323 g/day; P < 0.01) and lower feed conversion ratios than the other treatments. Dry matter and organic matter digestibility were not affected by the treatments, but neutral detergent fiber digestibility was significantly higher in the 30% green almond hulls treatment than in the other two treatments (P = 0.05). Consumption of green almond hulls resulted in a linear increase in glucose, total protein, and blood globulin in lambs (P < 0.01), while blood urea nitrogen tended to decrease (P = 0.06) and the albumin to globulin ratio decreased (P < 0.01). No statistically significant differences were observed for the concentration of cholesterol, triglycerides, and blood liver enzymes including aspartate aminotransferase and alanine aminotransferase in lambs among the experimental treatments.
Conclusion: In general, replacing 30% of the diet of feedlot lambs with green almond hulls increased the digestibility of neutral detergent fiber and improved growth rate and feed efficiency. Also, the increase in glucose and decrease in blood urea nitrogen indicated an improvement in metabolism in the treatments receiving 30% green almond hulls, which may be effective in improving the production performance of lambs. Therefore, the results of this study indicate that replacing part of the grains and forage with green almond hulls can, in addition to improving sheep performance, reduce human and livestock competition for the use of resources that are consumable for humans.
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