GM 09. Factors affecting losses in a dual purpose herd

Abstract

In order to study the causes of losses (mortality and involuntary culling) as well as non genetics and genetics factors which affect them, 2439 records from a dual purpose farm were used. All the animals grazed introduced pastures without supplementation. All cows are hand milked with their calves up to 8-12 months of age. The health plan included vaccinations and periodic check-ups for endo and ectoparasites.The factors studied were: year of birth (1986-1996), month of birth, sex, age of calf (1-12 month), herd (1-19), age of dam (1-10 calving) and breed group (1= Santa Gertrudis (SG), 2= high grade SG, 3= SG x Bos taurus). The causes of loss were: 1. accidents, 2. unknown, 3. respiratory and gastrointestinal illnesses, 4. poor nutrition, 5. infectious and parasitic illnesses, 6. genetic problems and 7. others. All the variables were analized by Chi Square test. The mains causes of loss were 3 (58.1%) and 4 (21.9%). Only year of birth, month of birth, age of calf and herd had significant effects (P<.01). It is necesary to establish strict management controls to reduce losses in the first two months of life.