The relationship between permanent incisor wear and mohair production and attributes in grazing adult Angora goats

Abstract

We aimed to quantify if and to what extent permanent incisor wear affected mohair production in adult Angora castrate goats. The goats were grazed on annual temperate pastures for 6 years. During their sixth year mohair was harvested every 6 months and liveweight measured. Incisors were inspected at age 6 years and the amount and pattern of wear quantified. Restricted maximum likelihood (REML) base models were developed to account for background sources of variation. Once a base model had been selected for each fleece attribute, an extra term for the linear effect of the first and other permanent incisor wear were added to the model. During the year mean liveweight, greasy mohair production, clean mohair production and mean fibre diameter were (S.D.): 55.6 (5.85)kg, 4.97 (1.00)kg, 4.16 (0.87)kg, 34.8 (4.02)μm. Mean wear on permanent first incisors was 9% (range 0–30%). There was little wear on other permanent incisors. Greasy fleece weight, clean fleece weight, staple length and fleece entanglement were reduced significantly with increased wear of first permanent incisors. There were no significant effects of incisor wear detected for nine other fleece attributes or liveweight. The results indicate that 30% wear of the permanent first incisors reduced greasy fleece production by 20% and reduced clean fleece production by 30%. Given the magnitude of the effects detected it is clear that relatively small amounts of wear of permanent incisors in adult Angora goats reduce production of mohair and consequently will reduce financial returns from mohair sales. The clear implication is that managers of mohair producing enterprises should assess the incisors of adult Angora goats and use this information in determining which animals to cull from their flocks.