Korreksiefaktore by seleksie van Merinoskape
| dc.contributor.advisor | Du Toit, J. J. | |
| dc.contributor.author | Kotzé, Francois de Klerk | |
| dc.date.accessioned | 2017-04-13T06:30:41Z | |
| dc.date.available | 2017-04-13T06:30:41Z | |
| dc.date.issued | 1971-01 | |
| dc.description.abstract | English: Investigation was conducted into the influence of the age of dam and twinning on body weight, greasy fleece weight and certain fleece characteristics on lambs up to the age of 10 months. The above-mentioned fleece characteristics included percentage clean yield, fibre diameter, staple length and crimps per inch (2.54 cm). The aim of this study was to establish correction factors for the selection of Merino lambs at an early age. 403 Merino lambs from three different flocks from the Southern Free State was used as experimental material. Because of the range in age between lambs at any stage after birth it was necessary to transform the body and greasy fleece weig.hts to a standard age. For this transformation the linear-and daycorrection methods were employed. The averages reached by the results of these two methods generally differed significantly from each other (P<0.05). In addition semi-logarithmic growth-curves for the different groups of lambs were drawn. The weights that were obtained on 60 and 120 days of age were compared with the average weights which were obtained from the above-mentioned two methods of transformation. From these results it was obvious that the daycorrection method had better results than the linear method if the right factor for the weight-gain per day was used. It was found that lambs of mature ewes on 60, 120, 190 and 303 days of age respectively weighed 1.1, 1.0, 0.8 and 0.9 kg heavier than lambs of young ewes, while twin lambs were 1.1 kg lighter than single lambs on 60 days of age. The differences in body weight between sexes on 60 and 120 days were non-significant. Statistically the differences between the two groups of lambs in greasy fleece weight, per cent clean yield, fibre diameter, staple length and crimps per inch (2.54 cm) were of no significance. | en_ZA |
| dc.description.abstract | Afrikaans: Ondersoek is ingestel na die invloed van die ouderdom van die moeder sowel as geboorte-aantal op liggaamsgewig, vaggewig en sekere vageienskappe soos skoonopbrengs, veseldikte, stapellengte en kartels per duim (2.54 cm) van lammers tot op 10-maande ouderdom. Die doel hiervan was om korreksiefaktore vir seleksie van Merino-lammers op 'n vroeë ouderdom daar te stel. As eksperimentele materiaal is gebruik gemaak van 403 Merino-lammers afkomstig uit drie verskillende kuddes in die suidelike O.V.S. As gevolg van die verskil in ouderdom tussen lammers was dit nodig om die waargenome liggaams- en vaggewigte na 'n standaard ouderdom te transformeer. Vir hierdie doel is die lineêre metode sowel as die metode van dagkorreksies gebruik. Die gemiddeldes soos bereken deur hierdie twee berekeningsmetodes het oor die algemeen statisties betekenisvol van mekaar verskil (p<0.05). Verder is semi-logaritmiese groeikurwes vir die verskillende groepe lammers getrek, waarvan die gewigte op 60- en 120-dae ouderdom vergelyk is met gemiddelde gewigte soos verkry volgens die genoemde twee metodes van transformasie. Hieruit was dit duidelik dat die metode van dagkorreksies 'n beter transformasie as die lineêre metode beraam, mits die regte faktor vir gewigstoename per dag gebruik word. Dit is gevind dat lammers van volwasse ooie op 60, 120, 190 en 303 dae ouderdom onder skeidelik 1.1, 1.0, 0.8 en 0.9 kg swaarder weeg as lammers van jong ooie, terwyl, tweelinglammers op 60-dae ouderdom 1.1 kg minder weeg as enkeling lammers. So is bevind dat hamellammers nie betekenisvol swaarder is as ooilammers op 60- en120-dae ouderdom nie. Ten opsigte van vaggewig, skoonopbrengs, veseldikte, stapellengte en kartels per duim (2.54 cm) is geen statisties betekenisvolle verskil tussen laniinersvan volwasse ooie en dié van jong ooie verkry nie . | af |
| dc.description.sponsorship | Wolraadfondskomitee | en_ZA |
| dc.description.sponsorship | Suid-Afrikaanse Wolraad | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11660/6070 | |
| dc.language.iso | af | af |
| dc.publisher | University of the Free State | en_ZA |
| dc.rights.holder | University of the Free State | en_ZA |
| dc.subject | Merino sheep | en_ZA |
| dc.subject | Lambs | en_ZA |
| dc.subject | Ewes -- Behavior | en_ZA |
| dc.subject | Dissertation (M.Sc.Agric. (Sheep and Wool Science))--University of the Free State, 1971 | |
| dc.title | Korreksiefaktore by seleksie van Merinoskape | af |
| dc.type | Dissertation | en_ZA |