An investigation of selected diseases and aspects of husbandry of working dogs on sheep farms and sheep and beef farms in New Zealand in 2010 : thesis submitted by Adam O'Connell to fulfil the requirements for the degree of Master of Veterinary Science in the Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University, Palmerston North, New Zealand

Abstract

A cross-sectional study of 202 working sheep dogs and 56 owners was undertaken in 2010 to investigate the dogs‟ age, gender, breed, body condition scores, aspects of their husbandry, prevalence of and risk factors for nematode and protozoan parasitism, and prevalence of and risk factors for chorioretinopathy in working sheep dogs. Owners were convenience sampled from the South-West Waikato and the Tux North Island Dog Trial Championship 2010. Two-way tables were used to explore the relationship between variables. Significance of association was assessed using a Chi-squared or Fisher exact test as appropriate with a p-value of < 0.05 considered significant. Faecal analysis found 68/170 dogs (40%) had a nematode and/or protozoan parasite infection. Nineteen per cent (33/170) were infected with parasites from the Nematode phylum: Toxocara canis (9/170, 5%), hookworms (Uncinaria stenocephala or Ancylostoma caninum) (20/170, 12%) or Trichuris vulpis (8/170, 5%). Prevalence of protozoan infections was: Sarcocystis spp. 35/170 (21%), Isospora canis or Isospora ohioensis 9/170 (5%), Neospora caninum and Hammondia heydorni 4/170 (2%) and Giardia spp. 13/170 (8%). Younger animals had a significantly higher prevalence of Toxocara canis (P< 0.0001) and Giardia spp. (P< 0.0001). Prevalence of chorioretinopathy in the working sheep dogs was 44/184 dogs (24%). Older animals and males had a significantly higher prevalence of chorioretinopathy than younger animals (P= 0.0007) and females (P< 0.0001) respectively. Body condition scores for 197 animals found that: 29 had a BCS less than or equal to 2/9, 78 had a BCS of 3/9, 77 had a BCS of 4/9 and 13 had a BCS equal to or greater than 5/9. The BCS varied significantly between breeds (P= 0.002) with Huntaways comprising 23/29 of the dogs who were BCS two or less. The mean age of the working sheep dogs was 4.8 years, 85/200 (43%) were Huntaways, 84/200 (42%) were Heading dogs and 173/191 (91%) of the working sheep dogs were entire. Seventy-eight per cent of owners fed their dogs a diet consisting of commercial food and home kill sheep meat once a day. This study concluded that gastrointestinal nematode and protozoan parasitism and chorioretinopathy are occurring in working sheep dogs. The aetiology of the chorioretinopathy is undetermined. Further farmer education on the use of anthelmintic and prevention of gastrointestinal nematode and protozoa parasites may be required.