Fleece production
Fleece production depends on the area of the skin and the number of follicles that have developed on it. The maximum number of follicles that can develop is determined genetically, but the actual percentage of the wool-bearing follicles depends on nutrition. The nutritional needs of sheep vary according to the different production stages. Secondary follicles (that determine fine wool production) develop during the third trimester of pregnancy. In this trimester the foetus’ nutritional needs also increase and the rumen capacity is at its lowest.
How to feed the ewe
It is crucial to supplement the ewe with the right quality and quantity feed to maximize the lamb’s potential to produce wool. The effect of nutrition on that lamb’s lifetime fleece production is permanent. Wool from lambs of ewes with insufficient nutrition during pregnancy have a higher fibre diameter and a lower fleece weight. Both these characteristics have a negative impact on the price paid for the wool.
Supplementation of the correct quality and quantity feed is crucial for fleece production. An energy deficiency is the most common nutritional deficiency. Along with low conception rates and low milk production, fleece production also slows down in times of energy shortage. A lower fleece weight, staple length and fibre diameter is evident during an energy shortage. Sometimes a break in the wool fibres occur. An increase of energy intake has a direct positive effect on wool growth (Doney, 1983). An increase in wool growth is directly related to increased feed intake (Ferguson, 1959).
Wool growth is a function of feed intake
It is clear that wool growth is a function of feed intake but understanding the true nutritional needs for fleece production is far more complex. When protein bypasses the rumen into the lower digestive tract a definite change in wool growth is observed (Kempton, 1978). The degree to which the animal can use this protein depends on its energy status. To manipulate wool growth, we need to understand the relationship between energy and bypass protein. Adding crude protein alone will not influence wool growth, because the protein in the feed will not necessarily reach the abomasum in the same form. Wool consists of keratin, which is a complex protein, containing 20 different sulphur-containing amino acids. The most known ones are lysine, methionine, cystine and biotin. Supplementation of the amino acids are expensive and one should make sure that the extra costs are covered by the profit. Protein supplementation by supplying urea does not have an effect on wool growth (Peirce et al., 1955).
The role of in sulphur in wool production
The most important mineral for wool production is sulphur (S). The sulphur content of keratin (the main component of wool) ranges from 2,7% to 5,4%. The sulphur is mostly contained in cystine but there are also smaller amounts of sulphur in cysteine and methionine (McGuirk, 1983) Other minerals like copper (Cu) play a role in fleece quality. Zinc (Zn) and selenium (Se) also benefit wool growth.
It is clear that nutrition for fleece production is no easy task. The correct amount of energy, sulphur-containing amino acids and minerals should be supplemented at the correct production stages of the sheep to sustain maximum wool production. The current high demand for wool makes it worth the effort to invest in nutrition for wool production. In most cases the margins for meat production also go up when feeding for wool production because it affects conceptions, multiple births and growth.
Research
De Heus is doing research in practice to find the best and most economical supplementation for better wool production. In the process De Heus has observed favourable results that have led to the development of the product, RumiLick® Fleece Booster. This product is in the process of registration.
