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dc.contributor.advisorVan der Merwe, H. J.
dc.contributor.advisorCruywagen, C. W.
dc.contributor.authorBronn, Pieter Coenraad
dc.date.accessioned2018-10-24T10:03:01Z
dc.date.available2018-10-24T10:03:01Z
dc.date.issued1987-06
dc.identifier.urihttp://hdl.handle.net/11660/9426
dc.description.abstractEnglish: An enormous potential for increased meat production exists in South African dairy herds. Dairy producers are often in doubt regarding the profitability of a veal production system. This is probably the most important reason why dairy producers are discouraged from rearing bull calves for veal production. This study was undertaken to determine the effecrt of various concentrate to roughage ratios on pre-weaning, as well as post-weaning growth, and veal production of Friesian bull calves. Twenty-four Friesian bull calves were randomly divided into three groups at an age of two days. All calves received whole milk at a rate of 10% of their initial body mass and were weaned at an age of 30 days. Complete rations, in milled form, were offered ad lib. from six days of age, and the following differences in concentrate to roughage ratios occured between the groups: 70:30; 77,5:22,5; 85:15. Water was freely available from six days of age. Crude protein content of all three rations was 18% until 12 weeks and 14% until 20 weeks of age. All calves were slaughtered at 20 weeks of age. At 10 weeks of age, all calves were subjected to a digestibility trial for a period of seven days. Apparent digestibility of dry matter, organic matter, ether extract, nitrogen-free extract, gross energy, as well as in vitro dry matter digestibility, gradually increased with an increase in concentrate content of the ration. No significant differences (P>0,05) in digestibility of crude protein and neutral detergent fibre (NDF) were detected between groups. An increase in concentrate content of the trial rations was accompanied by a highly significant (P<0,01) decrease in crude fibre digestibility. The apparent digestible crude protein- (%) and digestible energy content (MJ/kg) for the 70%-; 77,5%- and 85% concentrate rations were 12,60 and 13,27; 12,59 and 13,63; 13,19 and 14,58 respectively. No statistically significant (P>0,05) difference with respect to body mass gain occured between treatments. Except for one period (fourth month), no significant (P>0,05) differences in feed intake occured between groups. Feed intake tended to decline during both the pre- and post-weaning periods with an increase in concentrate content of the ration. Efficiency of feed conversion to live mass improved highly significantly (P<0,01) for the post-weaning period and significantly (P<0,05) for the total period as the concentrate content of the ration increased from 70 to 85%. There were no significant (P>0,05) difference in carcass mass and grading score between treatments. Dressing persentage was significantly (P<0,05) higher for the 85%- compared to the 70%- concentrate group. Where the purchasing price of maize was taken into account, gross margin was R112,52; R124,82 and R113,79 for the 70% - ; 77,5% - and 85% - concentrate treatments respectively. Where the net producer's price of maize was applicable, gross margin was R131,66; R145,57 and R134,98 for the 70%-; 77,5%- and 85% concentrate groups respectively. It was concluded that Friesian bull calves can be reared profitably for veal production at 20 weeks of age. Even at the current high prices of feed ingredients, promising gross margins are possible for veal production from dairy herds. The most economical results in this study realized with a concentrate to roughage ratio of 77,5 to 22,5.en_ZA
dc.description.abstractAfrikaans: In Suid-Afrikaanse suiwelkuddes is daar 'n geweldige potensiaal vir verhoogde vleisproduksie opgesluit. Suiwelprodusente betwyfel dikwels die winsgewendheid van 'n kalfsvleisproduksiestelsel. Hierdie is skynbaar die belangrikste faktor wat suiwelprodusente ontmoedig om bulkalwers vir die produksie van kalfsvleis groot te maak. Hierdie studie is onderneem om die invloed van verskillende kragvoer- tot ruvoerverhoudings op voorspeense-, sowel as naspeense groei, en kalfsvleisproduksie van Friesbulkalwers te bepaal. Vier-en-twintig Friesbulkalwers is op twee dae ouderdom ewekansig in drie groepe ingedeel. Alle kalwers het volmelk teen 10% van aanvangsmassa per dag ontvang en is op 30 dae ouderdom gespeen. Volledige rantsoene, in gemaalde vorm, is ad lib. vanaf ses dae ouderdom aangebied en verskille in kragvoer- tot ruvoerverhoudings tussen groepe was as volg: - 70:30; 77,5:22,5; 85:15. Water was vanaf ses dae ouderdom vryelik beskikbaar. Ruproteïeninhoud van al drie proefrantsoene was 18% tot op 12 weke en 14% tot op 20 weke ouderdom. Alle kalwers is op 20 weke ouderdom geslag. Op 10 weke ouderdom is alle kalwers vir sewe dae aan 'n verteringstudie onderwerp. Skynbare verteerbaarheid van droëmateriaal, organiese materiaal, eterkstrak, stikstofvrye ekstrak, bruto energie, sowel as in vitro verteerbaarheid van droëmateriaal, het stelselmatig toegeneem met 'n toename in kragvoerinhoud van die rantsoen. Geen betekenisvolle verskille (P>0,05) is in ruproteïen- en neutraal-onoplosbare vesel (NDF) - verteerbaarheid tussen groepe waargeneem nie. 'n Verhoging in kragvoerinhoud van die proefrantsoene het met 'n hoogsbetekenisvolle (P<0,01) daling in ruveselverteerbaarheid gepaard gegaan. Die skynbaar verteerbare ruproteïen- (%) en verteerbare energie-inhoud (MJ/kg) vir onderskeidelik die 70%-; 77,5%- en 85%- kragvoerrantsoene was 12,60 en 13,27; 12,59 en 13,63; 13,19 en 14,58. Geen statistiese betekenisvolle (P>0,05) verskille ten opsigte van liggaamsmassa het tussen die behandelings voorgekom nie. Voerinnames het op een periode na (maand 4), geen betekenisvolle (P>0,05) verskille tussen groepe getoon nie. Gedurende die voorspeense0, sowel as die naspeense proefperiodes, het voerinnames 'n dalende neiging getoon met 'n verhoging in kragvoerinhoud van die rantsoen. Die doeltreffendheid van voeromsetting na lewende massa het vir die naspeense periode hoogsbetekenisvol (P<0,01) en vir die totale proefperiode betekenisvol (P<0,05) verbeter namate die kragvoerinhoud van die rantsoen van 70 tot 85% toegeneem het. Geen statistiese betekenisvolle (P>0,05) verskille in karkasmassa en gradering het voorgekom nie. Uitslagpersentasie was betekenisvol (P<0,05) hoër vir die 85%- in vergelyking met die 70%- kragvoergroep. Bruto marge vir die 70%0-; 77,5%- en 85%- kragvoerbehandelings was onderskeidelik R112,53; R124,82 en R113,79 waar die aankoopprys van mielies in berekening gebring is. In die geval waar die netto produsentprys van mielies van toepassing was, was bruto marge onderskeidelik R131,66; R145,57 en R134,98 vir die 70%-; 77,5%- en 85% kragvoergroepe. Die gevolgtrekking is gemaak dat Friesbulkalwers winsgewend tot op 20-weke ouderdom vir die produksie van kalfsvleis grootgemaak kan word. Selfs met die huidige hoë pryse van voerbestanddele, is belowende bruto marges moontlik vir kalfsvleisproduksie uit suiwelkuddes. Die mees ekonomiese resultate in die huidige studie is met 'n kragvoer- tot ruvoerverhouding van 77,5 tot 22,5 gerealiseer.en_ZA
dc.description.sponsorshipDepartment of Agriculture and Water Supplyen_ZA
dc.language.isoafen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectCalvesen_ZA
dc.subjectCalves -- Feeding and feedsen_ZA
dc.subjectBeef cattle -- Carcassesen_ZA
dc.subjectBeef cattle -- Feeding and feedsen_ZA
dc.subjectDissertation (M.Sc.(Agric. (Animal Science))--University of the Free State, 1987en_ZA
dc.titleKragvoer- tot ruvoerverhoudings in volledige rantsoene vir friesbulkalwers in 'n kalfsvleisproduksiestelselen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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