Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Genetic selection for high milk production, type and appearance for the last 50 years has suppressed
secondary traits such as reproductive performance, productive life, health and survivability in the pure
milk breeds. The economic importance of these secondary traits in dairy production systems is the
basis for the interest seen in crossbreeding. The problem of growth rate of heifers, cow fertility,
reduced disease resistance and small body frame for beef production in Jerseys can be improved by
crossing Jerseys with dual purpose breeds, such as Fleckviehs which possess a more beef potential.
Against this background, this study aimed at comparing the production and reproduction of Jersey and
Fleckvieh × Jersey cows in a pasture-based system.
Milk recording was done according to standard milk recording procedures. Milk production (milk, fat,
and protein yield) was adjusted to 305 days of lactation and corrected for age at calving. Effects of
breed, parity, month and year were estimated for milk, fat and protein yield as well as fat and protein
percentage using general linear models procedure. The fixed effects identified as having significant
effects on milk, fat and protein yield were breed, parity and year. F×J cows produced significantly more milk than J cows (6141 ± 102 vs. 5398 ± 95 kg milk). Protein and fat yield were significantly
higher in F×J (201 ± 3 and 272 ± 4 kg, respectively) than in J cows (194 ± 2 and 246 ± 3 kg,
respectively). There percentages of fat and protein differed slightly between the two breeds with the
Jersey recording slightly higher percentages (4.61 ± 0.04 and 3.62 ± 0.03 %, respectively) compared
to the F×J cows’ percentages, which were, respectively, 4.47 ± 0.04 and 3.51 ± 0.03 %. It was
concluded that F×J crossbred cows were more productive than purebred J cows probably owing to
heterotic effects.
Heifers were inseminated at 13 months of age and cows 40 days post-calving. Using insemination
records and pregnancy check results, fertility traits were analyzed and compared between the two
breeds, using analysis of variance for continuous records. Conception age was the same for both
breeds resulting in a similar age at first calving. For cows, the interval from calving to first
insemination was significantly shorter (P <0.001) in crossbred cows being 76.7 ± 2.2 days compared
to 82.4 ± 2.5 days for purebreds. A larger proportion (P < 0.001) of 0.70 for crossbred cows was
inseminated within 80 days after calving compared to 0.54 for J cows. Although the absolute number
of days between calving and conception (DO) was lower for F×J cows in comparison to J cows (104.8
± 6.8 vs. 114.8 ± 8.1days, respectively), the difference was not significant. However, the proportion of
F×J cows confirmed pregnant by 100 days in milk was 0.79, which was higher (P < 0.001) than the
0.66 for J cows. Results indicate the potential of improving reproductive performance of J cows
through crossing with dual-purpose breeds. The beef production of purebred J and Fleckvieh x Jersey (F×J) bull calves was compared, where bull
calves were reared similarly for veal, i.e. carcass weight not exceeding 100 kg, or as steers for beef to
21 months of age. In both the veal and steer production systems, the mean birth weight were higher (P
< 0.001) for crossbred in comparison to J calves and steers (33.5 ± 1.2 kg vs. 27.9 ± 1.2 kg for veal)
and (33.4 ± 0.9 kg vs. 26.9 ± 0.9 kg for steers) respectively. The live weight at 6 months of age was
163.5 ± 3.9 kg for J bull calves, which was lower (P < 0.001) than that for F×J bull calves (180.6 ± 4.0 kg). The F×J bull calves had a significantly higher average daily gain (ADG) of 0.82 ± 0.02
kg/day compared to 0.73 ± 0.02 kg/day for J bulls. Marketing age differed (P < 0.001) in the veal
production system with F×J and J bull calves marketed at 7.1 ± 0.1 and 6.3 ± 0.1 months,
respectively. End live weight at 21 months of age was significantly higher (P < 0.001) in F×J bulls
(441.4 ± 14.9 kg) than the 322.6 ± 13.4 kg in J bulls; while ADG differed (P < 0.001) between the two
breeds being 0.64 ± 0.02 and 0.46 ± 0.0 kg/day in F×J and J bull calves, respectively. Crossbred steers
had a significantly higher carcass of 206.5 ± 8.9 kg compared to 157.9 ± 8.6 kg for J steers. Results
indicate the potential of improving beef production characteristics of the J cattle through
crossbreeding. / AFRIKAANSE OPSOMMING: Genetiese seleksie vir hoë melkproduksie, tipe en voorkoms die afgelope 50 jaar het sekondêre
eienskappe soos reproduksie, produktiewe lewe, gesondheid en oorlewing onderdruk in die suiwer
melk rasse. Die ekonomiese belangrikheid van hierdie sekondêre eienskappe in melkproduksie
stelsels is die basis vir kruisteling. Probleme soos groei tempo van verse, koei vrugbaarheid, verlaagde
weerstandbiedenheid teen siektes en klein liggaam raam vir vleisproduksie in Jerseys kan verbeter
word deur die kruising van Jerseys met ' n dubbele doel rasse, soos Fleckviehs wat beskik oor beter
vleis potensiaal. Teen hierdie agtergrond, is hierdie studie daarop gemik om produksie en reproduksie
van Jersey en Fleckvieh x Jersey koeie in 'n weiveld - gebaseerde stelsel te vergelyk.
Melk opname is gedoen volgens standaard melkaantekening prosedures. Melkproduksie (melk-, veten
proteïen opbrengs) was aangepas vir 305 dae van laktasie en gekorrigeer vir kalf ouderdom. ‘n
Algemene lineêre model was gebruik om die effekte van ras, pariteit , maand en jaar op melk-, vet- en
proteïen opbrengs sowel as vet- en proteïen persentasie te bepaal. Die vaste effekte geïdentifiseer met 'n beduidende effek op melk-, vet- en proteïen opbrengs was ras, pariteit en jaar. F × J koeie het
aansienlik meer melk as J koeie (6141 ± 102 teen 5398 ± 95 kg melk) produseer . Vet opbrengs was
aansienlik hoër in F × J koeie as in J koeie (272 ± 4 246 teen ± 3 kg vet). Proteïen opbrengs was ook
aansienlik hoër in F × J koeie as J koeie (201 ± 3 vs 194 ± 2 kg proteïen). Vet en proteïen persentasies
het geneig om effens te verskil met 'n klein effek (4.61 ± 0.04 % vet en 3.62 ± 0.03 % proteïen) vir J
koeie en (4.47 ± 0.04 % vet en 3.51 ± 0.03 % proteïen) vir F × J koeie. Daar is tot die gevolgtrekking
gekom dat F × J gekruisde koeie kan meer produktief wees as suiwer J koeie weens heterotiese
effekte. Verse kunsmatig geïnsemineer was op 13 maande ouderdom en koeie 40 dae na- kalwing aangehou
was. Met behulp van bevrugting en swangerskap rekords, is vrugbaarheid eienskappe ontleed en
vergelyk tussen die twee rasse, met behulp van ontleding van variansie vir deurlopende rekords.
Ouderdom van bevrugting was dieselfde vir beide rasse wat in 'n soortgelyke ouderdomsgroep was by
eerste kalwing. Vir koeie was die interval van kalf tot eerste inseminasie aansienlik korter (P < 0.001)
vir kruisgeteelde koeie wat 76.7 ± 2.2 dae in vergelyking met 82.4 ± 2.5 dae suiwerrasse is. ‘n Groter
proporsie ( P < 0.001) van 0.70 vir gekruisteelde koeie is binne 80 dae na kalwing geïnsemineer in
vergelyking met 0.54 vir J koeie. Alhoewel die absolute aantal dae tussen kalwing en opvatting (DO)
laer was vir F × J koeie in vergelyking met J koeie (104.8 ± 6.8 teen 114.8 ± 8.1dae, onderskeidelik),
is die verskil nie betekenisvol nie. Maar die verhouding van F × J koeie wat swanger bevestig is met
100 dae in melk was 0.79, wat hoër was (P < 0.001) is as die 0.66 vir J koeie. Resultate dui daarop dat
daar potensiaal is reproduktiewe prestasie te verbeter van J koeie deur kruisteling met 'n dubbel- doel
rasse. Die vleisproduksie van suiwer J en Fleckvieh x Jersey (F × J) bulkalwers vergelyk. Die bul kalwers is
soortgelyk grootgemaak vir kalfsvleis, d.w.s karkas gewig mag nie 100 kg oorskry as bulkalwers nie, en as osse vir vleis tot 21 maande oud. In die kalwers- en os produksie stelsels, was die gemiddelde
geboorte gewig hoër (P < 0.001) vir die kruise in vergelyking met J kalwers en osse (33.5 ± 1.2 kg
teen 27.9 ± 1.2 kg vir kalwers) en (33.4 ± 0.9 kg vs . 26.9 ± 0.9 kg vir osse) onderskeidelik . Die
lewendige gewig op 6 maande ouderdom was 163.5 ± 3.9 kg vir J bulkalwers en was hoër (P < 0.001)
vir F × J bulkalwers 180.6 ± 4.0 kg. Die F × J bul kalwers het 'n aansienlik ‘n hoër gemiddelde
daaglikse toename (GDT) van 0.82 ± 0.02 kg/dag in vergelyking met 0.73 ± 0.02 kg/dag vir J bulle.
Bemarkingsouderdom verskil (P < 0.001) in die kalf produksie stelsel met F × J en J bulkalwers
bemark op 7.1 ± 0.1 en 6.3 ± 0.1 maande , onderskeidelik. Finale lewendige gewig van 21 maande
oud was aansienlik hoër 441.4 ± 14.9 kg in F × J bulle as 322.6 ± 13.4 kg in J bulle , terwyl GDT hoër
was (P < 0.001), met 0.64 ± 0.02 kg/dag en 0.46 ± 0.0 kg/dag in F × J en J bulkalwers, onderskeidelik.
Gekruisde osse het 'n aansienlik hoër karkasgewig 206.5 ± 8.9 kg in vergelyking met 157.9 ± 8.6 kg
van J osse. Resultate dui daarop dat daar potensiaal is om die beesvleis produksie-eienskappe van die
J beeste te verbeter d.m.v. kruisteling.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/86433 |
| Date | 04 1900 |
| Creators | Goni, Sindisile |
| Contributors | Dzama, K., Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xvi, 63 p. : ill. |
| Rights | Stellenbosch University |
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