Korreksiefaktore by seleksie van Merinoskape

[摘要] English: Investigation was conducted into the influence of theage of dam and twinning on body weight, greasy fleece weight andcertain fleece characteristics on lambs up to the age of 10 months.The above-mentioned fleece characteristics included percentageclean yield, fibre diameter, staple length and crimps per inch(2.54 cm).The aim of this study was to establish correction factorsfor the selection of Merino lambs at an early age.403 Merino lambs from three different flocks from theSouthern Free State was used as experimental material.Because of the range in age between lambs at any stageafter birth it was necessary to transform the body and greasy fleeceweig.hts to a standard age. For this transformation the linear-anddaycorrection methods were employed. The averages reached by theresults of these two methods generally differed significantly fromeach other (P<0.05). In addition semi-logarithmic growth-curvesfor the different groups of lambs were drawn. The weights that wereobtained on 60 and 120 days of age were compared with the averageweights which were obtained from the above-mentioned two methods oftransformation. From these results it was obvious that the daycorrectionmethod had better results than the linear method if theright factor for the weight-gain per day was used.It was found that lambs of mature ewes on 60, 120, 190 and303 days of age respectively weighed 1.1, 1.0, 0.8 and 0.9 kg heavierthan lambs of young ewes, while twin lambs were 1.1 kg lighterthan single lambs on 60 days of age. The differences in bodyweight between sexes on 60 and 120 days were non-significant.Statistically the differences between the two groupsof lambs in greasy fleece weight, per cent clean yield, fibre diameter,staple length and crimps per inch (2.54 cm) were of nosignificance.

[发布机构] University of the Free State