Produktion av finfibrig ull genom avel och utfodring - inkorsning av merino i sveafårsbesättningar
To produce fine fibre wool as a complement to lamb meat production, Merino and Svea sheep are currently being crossbred in the county of Jämtland. The aim of this study was to evaluate growth and wool quality of the first crossbred lambs. In addition, a literature study about nutritional effects on wool production has been carried out.
The literature study showed that fine fibre wool should foremost be achieved through directed breeding. Nutritional requirements of the sheep at different stages of production should determine their feeding.
The project included animals from five different farms. Crossing Svea ewes with Merino rams produced a total of 40 lambs. There were also three control groups with Svea lambs and one group with crossbred lambs of Svea/Swedish Finewool Breed. Lamb weights were registered at different ages. Fibre length measurements and wool samples for fibre diameter analysis were taken twice from the crossbred lambs. After shearing, the wool was weighed and cleanliness was estimated.
Crossing with Merino produced smaller lambs. The mean corrected weight of the Merino crossbred lambs was 32 kg while the Svea lambs weighed 36,5 kg. This is, however, not a problem as the Svea sheep are considered larger than need be. There was no difference between the fibre diameter of the lambs at the two times of measurement. Their fibre diameter was also smaller than the mean value of their parents. This simplifies handling of the wool after shearing. The wool can be sorted with the assumption that the fibre diameter is equal or less than that of the parent mean. Due to possible faults in the lambs? wool, fibre analysis should still be done. Wool samples can be taken at 110 days of age.
At 150 days of age the wool length of the Merino crossbred lambs had exceeded 6 cm, whereafter shearing can be recommended. The amount of wool varied between 0,7 kg and 2,9 kg. The Finewool crossbred lambs had longer wool fibre but lower total amounts of wool. Crossing with Merino lead to shorter wool fibres but a denser wool coat and consequently a higher yield.
The environment in which the Merino crossbreds were kept also affected wool quality. The animals should be kept under roof before shearing, and straw should not be spread over them.