Relationship Between Body Conformation and Production in Dairy Goats

Abstract

Type appraisal is important in goat breeding, but few data on relationships between body conformation and milk production are available. About 20 to 30% of the variation of milk yield is explained by variation of body weight. The relationship is closest if weight is taken shortly after kidding. Udder volume increases linearly between milkings and is related with milk yield, which depends on empty udder weight and secretion per kilogram mammary tissue. Milk yield may be assessed by visual appraisal of udder size. Multiple regressions of milk yield on body measurements have positive relationships with body weight, skeletal size, abdominal volume, and udder volume but negative relationships with weight of body fat and muscles. This indicates that increased body weight favors milk yield only if it is due to scale while it reduces milk yield if due to fat and muscle mass. These relationships would disfavor increasing meat production from dairy goats, but due to a marked sex dimorphism male kids may be used for fattening. Multiple regressions also indicate that early maturing goats tend to produce less milk in their first lactations. About 70% of the variation of first milk production is explained by the common variation of body characteristics and growth rate. Heterozygous polled goats or those with wattles are more prolific than horned animals or without wattles. There is a need for better understanding of body characteristics having importance for adaptability and resistance to adverse environment conditions.