| BIOL-800 |
Wool Growth
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The wool-producing ‘factory’ is the 50 million or so follicles embedded in the skin of sheep. This unit covers in detail, how these follicles form, what cellular and molecular processes produce the fibre, how genetics and nutrition affect these processes, and how genetic engineering might be used to produce a better fibre. With an understanding of the biology of the skin and the fleece, the characteristics of the wool follicle and fibre can be related to production, technology and the processing of wool. |
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This theme examines the effect of hormones, nutrition and genotype on wool production (quantity & quality). |
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You can download all presentations for each Topic as PPT presentations within a compressed archive (.ZIP) using the link provided for each Topic. You can preview the PPT presentation for each Module in PDF format using the link provided for each Module. The PDF does not include the notes.
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| BIOL-800-050 |
The Effect of Genotype on Wool Growth |
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This topic demonstrates the variations in fleece characteristics between different strains of sheep. |
| BIOL-800-050-100 |
Whole body differences that affect wool production |
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This module demonstrates variations in fleece characteristics between different strains of sheep maintained under the same environmental conditions and describes the whole body differences that may give rise to these variations. |
| BIOL-800-050-200 |
The Environment of the Sheep |
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Variation in wool growth between sheep within genotypes reflect the effects of the environment and physiology of the sheep. Environmental effects include both the external environment of the sheep, such as climate and day length, and the internal environment of the sheep, such as pregnancy and disease. This module lists the components of the sheep’s environment. |
| BIOL-800-100 |
The Effect of Hormones on Wool Growth |
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The impact of the endocrine system on wool growth is examined in detail, including the effects of the catecholamines, growth hormones, cortisol, insulin, sex hormones, thyroxine and cytokines. |
| BIOL-800-100-050 |
Can Hormones or Methionine Improve Wool Production of Pregnant and Growing Sheep |
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This module describes how hormones or amino acids can be used to manipulate wool growth in pregnant and growing sheep. |
| BIOL-800-100-100 |
Indirect Effects of Hormones on Wool Production |
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This module summarises how indirect effects can influence wool production using nutrient partitioning as an example. |
| BIOL-800-100-150 |
Catecholamines and Wool Growth |
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This module describes the endocrine mechanisms involved in the short term response to stress and how it affects wool production. |
| BIOL-800-100-200 |
Stress Hormones |
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The response to stress can either be short or long term. This module describes the role and location of ACTH in the sheep. |
| BIOL-800-100-250 |
Stress Response of Sheep |
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This module describes how sheep respond to stress. Stress can be induced by animal-animal, animal-human interactions or in response to an immune reaction, for example in response to flystrike. |
| BIOL-800-100-300 |
The Effect of Cortisol on Wool Production |
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This module describes the endocrine mechanisms involved in the long term response to stress and how it affects wool production. |
| BIOL-800-100-350 |
The Effect of Growth Hormone and Insulin-like Growth Factor Interactions on Follicles |
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This module describes the location of growth hormone and IGF receptors and binding proteins in the follicle. |
| BIOL-800-100-400 |
The Effect of Growth Hormone on Wool Production |
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This module describes the effect of growth hormone on wool production. |
| BIOL-800-100-450 |
The Effect of Insulin on Follicles |
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This module describes the function of insulin in the body and its effect on the follicle. |
| BIOL-800-100-500 |
The Effect of Insulin-like Growth Factor on Wool Production |
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This module describes the effect of the insulin-like growth factors on wool production. |
| BIOL-800-100-550 |
The Effect of Photoperiod on Wool Growth |
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This module describes the effect of photoperiod on wool growth and the role of melatonin and prolactin. |
| BIOL-800-100-600 |
The Effect of Sex Hormones on Follicles |
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This module describes the function of gonadotropins (sex hormones) in the body and its effect on the follicle. |
| BIOL-800-100-650 |
The Effect of the Pituitary on Wool Production |
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This module describes the hypothalamic-pituitary axis and the effect of the pituitary on wool production. |
| BIOL-800-100-700 |
The Effect of the Thyroid on Wool Production |
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This module describes the effect of the thyroid gland on wool production. |
| BIOL-800-100-800 |
The Immune Response and Follicle Function |
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This module describes the effect the immune response may have on wool production. |
| BIOL-800-100-850 |
The Use of Hormones to Manipulate Annual Wool Production |
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This module describes how hormones may be used to manipulate wool production throughout the year. |
| BIOL-800-200 |
The Influence of Nutrition on Wool Growth |
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Relationships between skin and follicle traits, and wool growth are described. |
| BIOL-800-200-050 |
Relationship between fibre length and diameter |
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Nutrition is the major environmental factor influencing the realisation of genetic potential for wool production and wool quality. Wool growth rate is constrained by feed intake and the supply of protein, energy, vitamins and minerals provided by the diet. This module describes the how length and diameter of the fibre change under different conditions, for example, nutrition, cold stress, thyroidectomy, cortisol administration, season and unbalanced amino acid supply. |
| BIOL-800-200-100 |
Essential amino acids for wool growth |
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This module describes the effects of proteins with different amino acid composition on wool growth and lists the amino acids that are essential for wool growth. |
| BIOL-800-200-150 |
The effect of protein supply on wool production |
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This module describes the nutritional factors limiting wool growth and the response of wool growth to protein that is not degraded in the rumen. |
| BIOL-800-200-200 |
Lysine and wool growth |
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This module examines the effect of the amino acid lysine on wool growth. |
| BIOL-800-200-250 |
Sulfur amino acids and wool growth |
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Nutrition is the major environmental factor influencing the realisation of genetic potential for wool production. Wool growth rate is constrained by feed intake and the supply of protein and energy provided by the diet. This module illustrates that both cysteine and methionine are limiting amino acid for wool growth, that rumen by-pass proteins can improve wool growth, that cysteine supply can influence the proportion of paracortex in the fibre, the sources of cysteine for wool growth, the relationship between genetics and cysteine metabolism and discusses the potential that this has for genetic selection. |
| BIOL-800-200-300 |
Vitamins and wool growth |
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Nutrition is the major environmental factor influencing the realisation of genetic potential for wool production. Wool growth rate is constrained by feed intake and the supply of protein, energy, vitamins and minerals provided by the diet. This module examines the effect of vitamin A and D on wool growth. |
| BIOL-800-200-350 |
Zinc and wool growth |
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Nutrition is the major environmental factor influencing the realisation of genetic potential for wool production. Wool growth rate is constrained by feed intake and the supply of protein and energy provided by the diet. This module examines the effect of zinc on wool growth. |