Science and Engineering Faculty, Queensland University of Technology, Brisbane, Australia.
Appl Microbiol Biotechnol. 2020 Jul;104(13):5739-5748. doi: 10.1007/s00253-020-10656-2. Epub 2020 May 14.
The effective removal of dags (manure balls) from cattle, sheep and goats is a significant issue for the livestock industry. Dags are hard recalcitrant deposits composed of materials, such as faeces, hair, soil, urine, feed and straw, and attach to the animal through the hair rather than the skin. Dags build up during wet periods, especially on long haired breeds, and can weigh up to 40 kg per animal for cattle. Dag removal prior to slaughter reduces the risk of microbial meat contamination and damage to the hide during leather processing. Existing removal methods include hair trimming or extensive hose washing that can result in stress to the animal and increased costs. An alternative solution is the application of enzyme formulations that target specific components of the dag so they are more easily removed by washing. Enzymes are already used in other cleaning applications and are proven for the breakdown of materials such as lignocellulose, protein or starch that are found in dags. This mini-review discusses the challenges of current dag removal methods and the state of the art and feasibility of applying enzyme formulations for the effective removal of dags. Although enzyme formulations are yet to be tested in large-scale cattle trials and questions remain regarding how they would be cost-effectively applied to live animals, the results at laboratory scale suggest further research is warranted. Overall, enzymes present an environmentally friendly solution to the high costs and animal welfare issues of current dag removal methods through significant reductions in cleaning time and water use. KEY POINTS: • Dag formation on livestock is a major issue for industry and for animal welfare. • Current methods are costly and challenging for operators and the animal. • Enzymes can degrade dag components to aid release with keratinases showing promise. • Dag removal needs to be field tested, and positive business cases must be generated.
从牛、羊和山羊身上有效清除粪球（粪便球）是畜牧业的一个重大问题。粪球是由粪便、毛发、土壤、尿液、饲料和稻草等物质组成的坚硬难处理的沉积物，通过毛发而不是皮肤附着在动物身上。粪球在潮湿时期会积聚，尤其是在长毛品种中，对于牛来说，每只动物的粪球重达 40 公斤。在屠宰前清除粪球可降低微生物肉污染的风险，并减少在皮革加工过程中对皮张的损害。现有的清除方法包括毛发修剪或广泛的软管冲洗，这可能会给动物带来压力并增加成本。另一种解决方案是应用针对粪球特定成分的酶制剂，以便更轻松地通过冲洗去除。酶已在其他清洁应用中使用，并已被证明可分解粪球中存在的木质纤维素、蛋白质或淀粉等物质。本综述讨论了当前粪球清除方法的挑战，以及应用酶制剂有效清除粪球的最新技术和可行性。尽管酶制剂尚未在大规模牛试验中进行测试，并且关于如何将其经济有效地应用于活体动物的问题仍然存在，但实验室规模的结果表明，有必要进一步研究。总的来说，酶制剂为当前粪球清除方法的高成本和动物福利问题提供了一种环保的解决方案，通过显著减少清洁时间和用水量来实现。关键点：
• 牲畜上的粪球形成是行业和动物福利的主要问题。
• 目前的方法成本高，对操作人员和动物具有挑战性。
• 酶可以降解粪球成分以帮助释放，角蛋白酶显示出前景。
• 需要对粪球清除进行实地测试，并生成积极的商业案例。
