Kurukulasuriya Maheshika S, Silva Pradeepa, Dematawewa C M B, Ariyaratne H B S, Rajapakshe R P V J, Wickramaratne S H G, Jayasooriya L J P A P, Munasinghe D M S, Lokugalappatti L G S, Notter D R
Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Badulla 90000, Sri Lanka.
Faculty of Agriculture, University of Peradeniya, Peradeniya 20400, Sri Lanka.
Vet Parasitol Reg Stud Reports. 2018 Jan;11:41-48. doi: 10.1016/j.vprsr.2017.11.011. Epub 2017 Dec 2.
Goat farming plays an important role in the Sri Lankan rural economy. Sri Lankan indigenous (SLI) goats and their crossbreds are reared mainly under extensive management and indiscriminately exposed to pathogens and parasites. This study was designed to evaluate resistance to haemonchosis in SLI goats and their Jamnapari crossbreds (JCB) in the dry zone of Sri Lanka. Twenty SLI and 20 JCB 4-month-old male goats were artificially challenged with 5000 H. contortus L larvae Faecal egg counts (FEC), body weights, FAffa MAlan CHArt (FAMACHA®) scores, packed cell volumes (PCV), red blood cell counts, total and differential white blood cell counts, blood haemoglobin contents, serum total protein and albumin contents, and serum pepsinogen and antibody levels were determined at 0, 21, 28, 35 and 42days after challenge. Effects of measurement time were significant for all variables (P<0.05). Breed effects approached significance (P=0.06) and measurement time×breed interaction was significant (P<0.05) for FEC. Peak FEC occurred at day 35 in both goat types, and JCB goats had higher FEC than SLI goats at days 28 (P<0.001), 35 (P<0.10), and 42 (P<0.10). Means for FEC at day 35 were 1783±446 eggs per gram of feces (epg) for SLI kids and 3329±850 epg for JCB kids. Haematological parameters, serum chemistry, and FAMACHA scores suggested that SLI goats were recovering from parasitic infection by day 42, whereas JCB goats had increasing severity of anaemia. Means for PCV in SLI goats decreased from 26.8±0.7% at day 0 to 19.7±0.9% at day 35 and thereafter increased to 20.2±0.9% at day 42. Means for PCV in JCB goats declined from 25.9±0.6% at day 0 to 17.2±0.9% at day 42. Eosinophilia was observed in both genotypes. The JCB goats were heavier than SLI goats and had higher antibody titres, reflecting higher levels of parasitism. Both goat types significantly increased in body weight during the experiment and therefore tolerated parasite infection without severe production losses. We concluded that SLI goats were more resistant to haemonchosis than JCB goats, but that JCB goats were somewhat resilient to parasitic infection. Substantial variability in measurements associated with parasite infection in both breeds indicated potential to improve parasite resistance. Phenotypic information should be coupled with genomic information to identify appropriate breeding goals for future selection programs.
山羊养殖在斯里兰卡农村经济中发挥着重要作用。斯里兰卡本土（SLI）山羊及其杂交品种主要在粗放管理模式下饲养，且无差别地暴露于病原体和寄生虫环境中。本研究旨在评估斯里兰卡干旱地区SLI山羊及其与贾姆纳巴里山羊的杂交品种（JCB）对血矛线虫病的抗性。选取20只4月龄的SLI雄性山羊和20只4月龄的JCB雄性山羊，人工感染5000条捻转血矛线虫L3期幼虫。在感染后0、21、28、35和42天测定粪便虫卵计数（FEC）、体重、Faffa Malan Chart（FAMACHA®）评分、红细胞压积（PCV）、红细胞计数、总白细胞和分类白细胞计数、血红蛋白含量、血清总蛋白和白蛋白含量以及血清胃蛋白酶原和抗体水平。测量时间对所有变量均有显著影响（P<0.05）。品种效应接近显著水平（P=0.06），FEC的测量时间×品种交互作用显著（P<0.05）。两种山羊在第35天FEC达到峰值，在第28天（P<0.001）、35天（P<0.10）和42天（P<0.10），JCB山羊的FEC高于SLI山羊。SLI幼羊在第35天FEC平均值为每克粪便1783±446个虫卵（epg），JCB幼羊为3329±850 epg。血液学参数、血清生化指标和FAMACHA评分表明，到第42天SLI山羊已从寄生虫感染中恢复，而JCB山羊贫血严重程度在增加。SLI山羊的PCV平均值从第0天的26.8±0.7%降至第35天的19.7±0.9%，随后在第42天升至20.2±0.9%。JCB山羊的PCV平均值从第0天的25.9±0.6%降至第42天的17.2±0.9%。两种基因型均观察到嗜酸性粒细胞增多。JCB山羊比SLI山羊更重，抗体滴度更高，反映出寄生虫感染水平更高。在实验过程中，两种山羊体重均显著增加，因此能够耐受寄生虫感染且未造成严重的生产损失。我们得出结论，SLI山羊比JCB山羊对血矛线虫病更具抗性，但JCB山羊对寄生虫感染有一定的恢复能力。两个品种与寄生虫感染相关的测量结果存在很大差异，表明有提高寄生虫抗性的潜力。表型信息应与基因组信息相结合，以确定未来选育计划的合适育种目标。
