Abstract
Australian mohair is a highly sought-after product in international natural fibre markets for its superior quality. To maintain this demand, substantial effort has been directed at understanding the factors that influence mohair quality and how to improve it. This thesis comprises of five short studies aimed to investigate the effect of pre-weaning feeding, and age after weaning, on the follicle populations of Angora goats, with implications on reproductive efficiency and financial returns from mohair.
In study one, pregnant Angora does were supplementary fed during days 60-90 or 120-180 post conception. Skin biopsies and fleece samples were taken from kids at birth, 1 week, 1 month, 2 months and 4 months of age. These samples were examined to determine the primary (P) and secondary (S) follicle densities and S:P ratio. Supplementary feeding during either time had no effect on follicle densities or S:P ratio.
In study two, the effect of age on follicle densities and S:P ratio was investigated by taking skin biopsies and fleece samples from 75 mature Angora goats aged from 6 months to 16 years. Although a significant correlation was found between age and S:P ratio, S follicle density, P follicle density and total follicle density, greater variation was explained by body weight than by age.
In study three, kids were selected at weaning and assigned to high and low postnatal nutrition groups with 12 and 13 replicates. Skin biopsies, fleece samples and body weight data were collected. Follicle densities and S:P ratio was similar between groups, however low nutrition status kids had lower body weights. Mean fibre diameter was also similar between nutritional groups but fleece weight was lower in kids from the low nutrition cohort.
In study four, reproductive records of a commercial Angora flock from 2017 to 2021 were examined to determine reproductive efficiency. Overall reproductive efficiency (kids weaned per 100 does bred) was 50%. Preweaning mortality was a major source of inefficiency, with starvation-mismothering-exposure being the primary cause of death.
In study five, gross margin scenarios were constructed to investigate the financial effect of feeding does for high or low S:P ratio progeny. Six scenarios were considered, in which does were fed for high or low S:P ratio progeny, with or without wethers and high and low stocking rates. Feeding does for high S:P ratio progeny and retaining wethers improved gross margins, while lower stocking rates did not. The major factors contributing to financial loss from an Angora enterprise were doe mohair quality and cost of supplementary feed.
While genetics has a marked effect on follicle development, nutrition during gestation and lactation enables the greatest potential of the follicle population to be achieved by maximising the number of follicles that initiate and mature respectively. Selection of replacement breeding animals should consider follicle density in conjunction with body weight and reproductive performance. This will improve the financial returns for an Angora enterprise.
In study one, pregnant Angora does were supplementary fed during days 60-90 or 120-180 post conception. Skin biopsies and fleece samples were taken from kids at birth, 1 week, 1 month, 2 months and 4 months of age. These samples were examined to determine the primary (P) and secondary (S) follicle densities and S:P ratio. Supplementary feeding during either time had no effect on follicle densities or S:P ratio.
In study two, the effect of age on follicle densities and S:P ratio was investigated by taking skin biopsies and fleece samples from 75 mature Angora goats aged from 6 months to 16 years. Although a significant correlation was found between age and S:P ratio, S follicle density, P follicle density and total follicle density, greater variation was explained by body weight than by age.
In study three, kids were selected at weaning and assigned to high and low postnatal nutrition groups with 12 and 13 replicates. Skin biopsies, fleece samples and body weight data were collected. Follicle densities and S:P ratio was similar between groups, however low nutrition status kids had lower body weights. Mean fibre diameter was also similar between nutritional groups but fleece weight was lower in kids from the low nutrition cohort.
In study four, reproductive records of a commercial Angora flock from 2017 to 2021 were examined to determine reproductive efficiency. Overall reproductive efficiency (kids weaned per 100 does bred) was 50%. Preweaning mortality was a major source of inefficiency, with starvation-mismothering-exposure being the primary cause of death.
In study five, gross margin scenarios were constructed to investigate the financial effect of feeding does for high or low S:P ratio progeny. Six scenarios were considered, in which does were fed for high or low S:P ratio progeny, with or without wethers and high and low stocking rates. Feeding does for high S:P ratio progeny and retaining wethers improved gross margins, while lower stocking rates did not. The major factors contributing to financial loss from an Angora enterprise were doe mohair quality and cost of supplementary feed.
While genetics has a marked effect on follicle development, nutrition during gestation and lactation enables the greatest potential of the follicle population to be achieved by maximising the number of follicles that initiate and mature respectively. Selection of replacement breeding animals should consider follicle density in conjunction with body weight and reproductive performance. This will improve the financial returns for an Angora enterprise.
Original language | English |
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Qualification | Master of Philosophy |
Awarding Institution |
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Supervisors/Advisors |
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Award date | 14 Dec 2022 |
Place of Publication | Australia |
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Publication status | Published - Dec 2022 |