Die invloed van voedingspeil op puberteitsbereiking by Nguni, Bonsmara en Drakensbergerverse

Abstract

The effect of feeding level on puberty development in Nguni, Bonsmara and Drakensberger heifers. The growing interest in the Nguni and the need for reliable data on the breed led firstly to an investigation of puberty development in Nguni, Bonsmara and Drakensberger heifers. Secondly puberty development was also studied in Nguni heifers under extensive conditions. Nguni heifers reached puberty at a highly significant (P < 0,01) earlier age (349,91 days) and lower mass (238,23 kg) as compared with Drakensberger and Bonsmara heifers. The Drakensberger heifers were slightly younger (407,21 days) and lighter (298,71 kg) than the Bonsmara heifers which were 418,96 days old and with a mass of 341,39 kg. The Bonsmara, Drakensberger and Nguni heifers gained 1080, 870, and 760 g per day, respectively, from weaning to the attainment of puberty. Nguni heifers consumed significantly less feed (326,8 kg) compared to the Drakensberger (780,27 kg) and Bonsmara heifers (1 151,27 kg). At puberty the Nguni heifers were the smallest. The Drakensberger and Bonsmara heifers had approximately the same stage of conformational development. The group of Nguni heifers which were under intensive feeding conditions, maintained a highly signifIcant (P < 0,01) higher ADG, attained puberty at a highly signillcant (P < 0,01) earlier age (344,51 versus 399,89 days) and on a slightly though nonsignificant lower mass (237,27 vs 234,85 kg) than the group under extensive conditions.

Die groeiende belangstelling in die Nguni en die behoefte aan betroubare inligting oor die ras het eerstens gelei tot 'n ondersoek na puberteitsontwikkeling by Nguni, Bonsmara en Drakensbergerverse onder intensiewe voedingstoestande, Tweedens is puberteitsontwikkeling ook by Nguniverse onder ekstensiewe toestande bestudeer. Nguniverse het puberteit op 'n hoogs betekenisvolle (P< 0,01) vroeë ouderdom (349,91 dae) en ligter massa (238,23 kg) bereik vergeleke met Drakensberger en Bonsmaraverse. Drakensbergerverse was met puberteit ietwat jonger (407,21 dae) en ligter (298,71 kg) as die Bonsmaraverse wat 418,96 dae oud was en 'n massa van 341,39 kg gehad het. Bonsmara, Drakensberger en Nguniverse het vanaf speen tot met die bereiking van puberteit, respektiewelik 1 080, 870, en 760 g per dag gehandhaaf. Nguniverse het heelwat minder voer verbruik (326,8 kg) vergeleke met die Drakensberger (780,27 kg) en die Bonsmaraverse (1 151,27 kg). Nguniverse was met puberteit kleiner as die Bonsmara en Drakensbergerverse wat op hulle beurt puberteit nagenoeg op dieselfde stadium van bouvorm ontwikkeling bereik het. Die groep Nguniverse wat onder intensiewe voedingstoestande 'n hoogs betekenisvolle (P < 0,01) hoër GDT gehandhaaf het, het puberteit op 'n hoogs betekenisvolle (P< 0,01) vroeër ouderdom (344,51 teenoor 399,89 dae) en ietwat swaarder (237,27 teenoor 234,85 kg) maar nie betekenisvolle hoër massa, bereik as die groep onder ekstensiewe toestande.

Keywords: Nguni, puberty, feeding level