| dc.description.abstract | Data on reproductive performance and pre-weaning growth
of pigs from three large scale herds in Kenya were studied to
evaluate means and the effects of genetic and environmental
factors on sow and piglet performance. The data comprised
1646 Landrace, Large White and Hampshire litter records from
Zea, Ngata and Lanet herds and 2861 Landrace and Large White
weaner records from Lanet. The records spanned a period of
15 years (1975-89). Sow traits studied were litter size at
farrowing (LSF) and at weaning (LSW), litter weight at 3
weeks (LW3), litter weight at weaning (LWW) , average piglet
weight at birth (ABW) and at weaning (AWW) and farrowing
interval (FI). Piglet traits studied were weaning weight
(Ww) and pre-weaning average daily gain (ADG).
Litter size at farrowing averaged 9.78±2. 42 in Large
White sows from Lanet, 8.79±2.41 ln Landrace sows and
7.08±2.64 in Hampshire sows. Litter size at weaning averaged
8.09±1.61 and 7.47±1.40 in Large White sows from Lanet and
Landrace sows respectively. Piglet weight at birth averaged
1.45±.19 kg in Large White sows from Lanet, 1.46±.22 kg in
Landrace sows and 1.53±.29 kg ln Hampshire sows. The
farrowing interval, average litter weight at weaning and
average piglet weight at weaning in Landrace sows were
194.46±33.08 days, 95.40±23.50 kg and 12.94±2.4S kg
respectively. Landrace piglets grew faster and were heavier
(P<O.Ol) at weaning than Large White piglets. Entire males
excelled both females and castrates in growth rate and
average weaning weight.
Parity effects were significant for LSF, FI and litter
weights. LSF peaked in the third and fourth parities in the
Large White and Landrace sows respectively. Year and season
of farrowing influenced growth traits and LSW. Growth
performance and litter size at weaning declined in the latter
half of the periods studied in the herds at Lanet and 2ea.
Inbreeding depression was considered a likely rea~on for t~e
decline. At Lanet piglets born between September a~d March
grew faster and were heavier (P<O.Ol) at weaning than those
born during the rest of the year but the interaction between
year and season of birth was significant.
Heritability estimates from paternal half-sibs were
O.21±.08, O.19±.08, O.13±.07, O.15±.08, O.17±.08, O.23±.09
and O.43±.12 for AEH, L\>,13, LF",yand FT- ,
respectively, in the Landrace breed. Heritability and
repeatability estimatEs for reproductive traits we r s
generally low. Genetic correlations between litter size and
litter weights ranged from O.94±.10 to O.96±.04, while the
corresponding phenotypic correlations ranged from 0.50 to
O. 7~, .
were positive and high. It was concluded that selection for
hi9h L1--Dwou Ld be expected to improve Lr".,lI~. | en |
