Comparative Study of the Growth and Carcass Characteristics of the Nigerian Indigenous and Large White Pigs
The growth and carcass characteristics of Large White (LW), Nigerian Indigenous (NI) and their F1 crossbred (LWxNI) pigs were compared across various ages. A total of 51 pigs were used in the study, which comprised 22 NI (12 boars and 10 gilts), 20 LW (10 boars and 10 gilts) and 9 LWxNI crossbred pigs (3 boars and 6 gilts). The three breeds were managed in a similar fashion and slaughtered at 34 weeks of age. There were significant differences (p<0.01) in live weight, Average Daily Gain (ADG), Average Daily Feed Intake (ADFI) and Feed Conversion Ratio (FCR) among the NI, LW and LWxNI (F1) crossbred pigs. At 10 weeks of age, LW boars had significantly higher ADG (125.7 g day-1 versus 78.3 g day-1) and consumed more feed (326.2 g day-1 versus 146.8 g day-1) than the NI boars. Differences in FCR between the NI and LW boars were significant at 25 weeks of age (p<0.05). At similar live weights, LW pigs were significantly (p<0.01) younger and had higher in ADG, ADF1 and FCR values than the other breeds. The carcass of NI male pigs yielded significantly (p<0.05) higher percent lean (53.3% versus 40.0%), higher four lean cuts (57.7% versus 55.0%), higher percent shoulder (20.1% versus 17.6%) but lower dressing percentage (64.6% versus 69.2%) than in the LW male pigs. It is therefore concluded that whereas the NI pigs grew poorly when compared to the LW counterparts, they possess some superior carcass characteristics.
Significant improvements in the level of education and per capita incomes are
expected in the developing countries and this is expected to result in increased
demand for meat and meat products (FAO, 2000). Consequently, several strategies
for enhanced meat production have been adopted at both local and international
levels. Some of these measures involved large scale transfer of modern scientific
practices from developed countries into the developing world. Unfortunately,
most of these introductions have been met with failures due to a lack of basic
technical expertise and varying degrees of difficulties in adapting them to
local conditions. In livestock production, more attention is being given to
farming of indigenous species for meat production. Indigenous species are known
to perform relatively well under harsh tropical conditions often characterized
by feed scarcity and disease challenge. Owing to the critical role played by
pork and pork products nutritionally worldwide, several importations of exotic
breeds of pigs have been made into Nigeria for either production or to improve
the quality of the indigenous stock. Agbagha et al. (2001) observed that
cross breeding for improvement of local breeds have not yielded any significant
positive economic results. Most of these exotic breeds have either performed
below expectation or failed to adapt and produce under local conditions. The
most significant success in this respect was recorded among the Large White
breeds of pigs (Payne, 1990). Umesiobi (2000) described the Nigerian Indigenous
pigs as poor producing non-descript animals, which are not fit to be integrated
into modern living and livestock husbandry. However, no documented evidence
was presented in support.
The few and available studies on the productivity and carcass characteristics of the NI pig show generally that they have inferior growth and carcass characteristics when compared to the exotic breeds. Fetuga et al. (1977) reported that the LandracexLarge White cross bred (LRxLW) boars were superior to the NI pigs in live weight and number of days required to reach predetermined slaughter weights. Reported values for ADG vary among authors. Fetuga et al. (1977) reported 0.32 kg day-1 for the LRxLW cross breed, Sonaiya (1986) reported a value of 0.14 kg day-1 for the NI pig, whilst Adebambo and Onakade (1983) reported 0.30 kg day-1 for the NIxHampshire crossbreed. Fetuga et al. (1976a) observed that the LWxNI crossbred pigs were leaner, contained more bone and less skin than the local pigs across all slaughter weights. Fetuga et al. (1976b) observed that the dressing percentage was significantly higher in NI pigs compared to LWxLR pigs and attributed this to increased fat content of carcasses from the indigenous pigs. Cameron and Ashton (1969) had earlier reported the values of 85.1%, 3.7 cm and 21.9 cm2 for the dressing percentage mean back fat depth and loin-eye muscle area, respectively, among the local black pigs of Ghana. Adebambo (1983) reported that the F2 progenies having 50% LW, 25% NI and 25% Hampshire (HA) blood had 7 to 10% less muscle depth and 11 to 15% less rib-eye muscle area than the pure LW progenies.
Compared with the exotic breeds, the indigenous breed has received very little research attention and is even in danger of extinction. Moreover, detailed and comprehensive reports comparing the carcass attributes of the NI breed with the widely adapted LW are scarce and probably non-existent. This study was therefore designed to compare the growth performance and carcass characteristics of the Nigerian Indigenous breed with the Large White and their F1 crossbreeds, across various live weights and ages.
MATERIALS AND METHODS
A total of 51 piglets comprising 22 NI (12 males and 10 females), 20 Large
White (10 males and 10 females) and 9 crosses (3 males and 6 females) were used
in the experiment. All piglets were weaned at 5 weeks of age and each breed
pooled into a large pen.
Feeding and Management of Experimental Animals
All the experimental animals were fed a corn-groundnut cake based ration
formulated as shown in Table 1 and 2. Four
feeding regimes were adopted namely: Pre-starter (5-10 weeks of age): Starter
(11-15 weeks); Growing (16-25 weeks) and Finishing (26-34 weeks). No creep feeding
was provided but piglets were allowed unlimited access to the dams ration
which was formulated to provide 14.78% CP and 10.91 MJ kg-1 ME during
the pre-weaning days. Pigs were fed in groups once a day, with a quantity of
feed estimated at 6% of the total body weight at the end of the preceding week.
Leftovers were collected daily and weighed and water was provided ad libitum.
The animals were initially housed 5 to 6 piglets per pen and gradually reduced
to 3 as body weight increased. All the animals were managed in a similar fashion
and the minimal space allowance was estimated according to the Recommendation
of the Canadian Council Guidelines for the Care and Use of Experimental Animals,
Animal Slaughter and Determination of Carcass Characteristics
At the age of 34 weeks, 5 animals were randomly selected from each of the
NI males, LW males and LW females and starved for 24 h, while water was provided
ad libitum. The animals were weighed and stunned manually using the hammer
method, shackled and bled in a vertical position by severing the jugular veins.
||Ingredient composition of experimental diets
|*Vitan: a multivitamin and mineral premix. One kilogram contains
Vitamin A, 8,000,000 IU; vitamin D, 1600000 IU; vitamin E, 5000 IU; vitamin
K, 2000 IU; vitamin B1, 1500 mg; vitamin B2, 4000 mg; vitamin B6, 1500 mg;
vitamin B12, 10 mg; niacin, 15000 mg; pantothenic acid, 5000 mg; folic acid,
5000 mg; biotin, 20 mg; choline chloride, 125 g; antioxidant, 125 g; manganese,
50 g; zinc, 50 g; copper, 5 g; iodine, 1.2 g; selenium, 200 mg; cobalt,
||Calculated nutrient composition of the experimental diets
|NDF = Neutral Detergent Fiber; ADF = Acid Detergent Fiber
They were allowed to bleed completely for 15 min. After bleeding the deadweight
was measured. The difference between the live and deadweight was calculated
and recorded as the weight of blood. The carcasses were dressed and cut into
the different joints as described in the FAO Guidelines for the Slaughter, Meat
Cutting and Further Processing (FAO, 1991). Each joint was weighed and recorded.
Thee rib-eye area and back fat thickness were determined by tracing with acetate
paper, according to the method described by Burson (2001). The back fat measurements
were taken only at the 10th rib whereas rib-eye area was taken at 10th and last
ribs of the right side.
Data Collection and Statistical Analysis
Data was collected every week on live weight gain and feed consumption from
5 to 25 weeks of age. These were used to compute the Average Daily Gain (ADG),
Average Daily Feed Intake (ADFI) and Feed Conversion Ratio (FCR) (ADG/ADFI).
Data on growth performance was analyzed at 5, 10, 15 and 25 weeks of age using
the Completely Randomized Block Design (CRBD). Breed and sex served as treatments
while age served as blocks. In order to remove variation introduced by differences
in live weight on growth performance parameters, the mean ADG, ADFI and FCR
and average daily feed intake per unit live weight at similar live weights of
approximately 3, 4.5 and 6.5 kg, were determined for each sex in the three breeds.
These were also analyzed using CRBD with the fixed live weights serving as blocks.
Since all animals were slaughtered at the same age (34 weeks), carcass characteristics
were analyzed using the Completely Randomized Design (CRD). Analysis of variances
was carried out on all the parameters and means separated by the Least Significant
Difference (LSD) as described by Little and Hills (1978).
Growth and Feed Intake
The comparisons of the live weight, growth performance, feed intake and
feed conversion ratio between the NI, LW and their FI crosses at 5, 10, 15 and
25 weeks of age are shown in Table 3. The average live weight
of the pigs showed much variation across and within the breeds. The live weights
were not significantly different (p>0.05) until the age range of 15 to 25
weeks. At the 15th week of age, LW males and females were significantly heavier
than NI males and F1 males (p<0.01) whereas the live weights of LW males
and females, NI females and F1 females were similar (p>0.05). At the 25th
week of age, NI males and females and the F1 males were similar in live weight
(p>0.05), but significantly (p<0.05) lower than the F1 females. LW males
were significantly (p<0.05) heavier than the LW females. The Average Daily
Feed Intake (ADFI) varied significantly (p<0.01) across the different ages
and breeds. At 10 weeks of age, the LW pigs consumed significantly (p<0.05)
more feed than the NI and the F1 crossbred pigs. Females consumed significantly
(p<0.05) less feed among the LW breed but more among the NI and the F1 crossbred
pigs at 25 weeks of age.
The feed conversion ratio (FCR) decreased significantly (p<0.05) from the
10th to 25th weeks of age among the NI male pigs but was similar (p>0.05)
among the LW males. Intra-breed variation due to sex was not significant (p>0.05)
in all the breeds and ages except among the NI at 25 weeks of age and the LW
pigs at 15 weeks age. When the average daily gains at similar weights (3.0,
4.5 and 6.5 kg) were compared (Table 4), irrespective of the
age, it was discovered that among the three breeds, live weight had no effect
on gain (p>0.05).
||Growth performance of Nigerian indigenous, large white and
their F1 crosses at various ages
|a, b, c,..., m Means within a row or
column with a similar superscript are not significantly different (p>0.05)
ADG = Average Daily Gain; ADFI = Average Daily Feed Intake; FCR = Feed Conversion
Ratio; NI = Nigerian Indigenous; LW = Large White; F1 = NI x LW cross bred
||Average daily gain, average daily feed intake and efficiency
of Nigerian Indigenous, Large White and their F1 crosses at 3, 4.5 and 6.5
kg mean live weights
|a, b, c,..., m Means within
a row or column with a similar superscript are not significantly different
(p>0.05)ADG = Average Daily Gain; ADFI = Average Daily Feed Intake; FCR
= Feed Conversion Ratio; NI = Nigerian Indigenous; LW = Large White; F1
= NIxLW cross bred pigs
||Plot of live weights of Nigerian Indigenous (NI), Large White
(LW) and their F1 cross (F1) pigs against age
||Plot of the Average Daily Gain (ADG) of the Nigerian Indigenous
(NI), Large White (LW) and their F1 crosses against age
Gain varied very significantly (p<0.01) across the breeds. LW pigs grew
significantly (p<0.5) more than NI pigs whilst NI pigs were similar to F1
crosses. Males had lower growth rates among the NI and F1 crosses, but higher
values among the LW breeds. At 6.5 kg live weight; LW males consumed more feed
than LW females (307.25 g versus 218.44 g). The LW breed was significantly (p<0.05)
more efficient in gaining weight than the NI and F1 crossbred pigs. Neither
breed nor sex had any significant effect on ADFI per unit live weight.
Figure 1 is the growth curve of the three breeds of pigs.
The curves show that the growth pattern of the three breeds of pigs are similar
and resemble the sigmoid curve. A closer assessment shows that the Large White
pigs had higher live weights when compared to the locals and the crosses at
all ages from three weeks of age.
||Plot of the Average Daily Feed Intake (ADFI) of the Nigerian
Indigenous (NI), Large White (LW) and their F1 Crosses (F1 Cr) against age
||Plot of the efficiency off feed conversion (ADG/ADFI x100)
of the Nigerian Indigenous (NI), Large White (LW) pigs and their F1 crosses
The NI and F1 crosses had similar weights up to the age of 17 weeks such that
significant effect of crossing both breeds in the F1 generation was observed
from 18 weeks of age. The plot of the ADG against age is shown in Fig.
2. The pattern is similar in all the three breeds. ADG was highest within
the first two weeks of life and dropped progressively to the minimal values
at 6 weeks in LW and NI pigs. From 7 to 25 weeks of age, the ADG among the LW
pigs progressively increased from 80 to 142 g day-1 whereas among
the NI pigs, the increase was sustained only to the 11th week of age (30 to
80 g day-1) and then dropped to 38 g day-1 at 25th week
of age. The ADG of the crossbred pigs decreased from 131 g day-1
at 1 week to 66 g day-1 at 2 weeks, a level which was fairly maintained
until 10th week of age. Subsequently, the ADG fluctuated throughout the remaining
experimental period. Figure 3 shows the plot of the Average
Daily Feed Intake (ADFI) against age. Feed intake increased regressively from
6 to 34 week of age in all the breeds. The LW consumed more feed than the NI
but the curve patterns were similar in all breeds throughout the period of trial,
although deflections occurred at certain points. The F1 crosses had similar
intakes with the NI until 15 weeks of age. After 15 weeks, intake among the
crosses was higher than in the NI. Feed intakes by the crossbreeds were even
higher than those of the LW at 17 weeks. The trends in efficiency of gain of
the three breeds are shown in Fig. 4. The curve of the LW
decreased progressively from 7 to 25 weeks of age. The pattern was similar among
the NI and LW breeds, except during the first few weeks of life. Between 9 and
12 weeks of age, the NI pigs had higher efficiencies of gain while the LW had
higher values throughout the rest of the experiment. The pattern for the F1
crossbreed was markedly different. It had two notable peaks, at the 11th and
21st weeks of age.
The carcass characteristics of NI (males) and LW (males and females) are
presented in Table 5. The results show that the LW pigs had
significantly higher (p<0.01) live weights at slaughter than the NI pigs.
The LW males had higher live weights than females (p<0.05). Although carcass
length was similar in LW males and females (p>0.05), the males had significantly
higher carcass weight than the female counterpart (p<0.01). The LW males
and females had significantly (p<0.05) higher carcass weight and carcass
length than the NI pigs.
||Carcass characteristics of local and large white pigs
|a, b and c means with different superscripts
are significantly different (p<0.05) SFFL (NNPC Standardized Fat Free
Lean) = 8.588 + (0.465xhot carcass wt., lb)-(21.896x10th rib back fat
thickness, in) + (3.005x10th rib eye muscle area, sq. in) n.d. = not determined
There were sex differences in dressing percentage. The NI males and LW females
were significantly (p<0.05) lower than the LW males in dressing percentage.
The mean percentage offal content of NI pigs was significantly (p<0.01) higher
than the value for LW. The Longissimus dorsi cross sectional area (rib-eye
area) of the LW pigs was significantly (p<0.01) larger than that of the NI
pigs. No significant sex differences were found in the rib-eye area of LW pigs.
The percentage ham content was similar in all breeds whilst NI male pigs had
significantly (p<0.01) higher shoulder cut (20.14%) than the LW male pigs
(17.2%). The LW male and female pigs had significantly (p<0.01) higher percentage
belly cut than the NI male pigs. Within the LW breed, there was a significant
(p<0.01) sex difference for 10th rib back fat thickness, carcass weight and
dressing percentage. When the trimmings (trotters, tail, jowl meat) were evaluated,
the LW pigs were found to have significantly (p<0.01) higher percentage compared
to the NI breed (8.45% vs. 3.88%). The NI have a higher proportion of the four
lean cuts (shoulder, ham, loin and spare ribs), 57.9% compared to 55.1% in LW
males and 53.7% in LW females. The NI pigs had higher percent Standardized Fat
Free Lean (SFFL), showing that they deposited more lean. The NI pigs yielded
higher proportion of offal except the GIT, though the latter was not significantly
different (p>0.05). The proportions of the internal organs such as heart,
liver, spleen, testes, kidney and lungs were similar in both sexes of LW pigs
(p>0.05), both of which were significantly (p<0.05) lower than the values
for the NI male pigs.
Our results demonstrate significant breed differences in the rate of live weight
gain, average daily feed intake and feed efficiency (Table 3).
Fetuga et al. (1976a) and Fetuga et al. (1977) also reported that
there were highly significant breed differences for growth, feed efficiency
and carcass characteristic between the NI and imported European breeds. Fetuga
et al. (1976a) observed that the maximum growth rate occurred in the
growth phase between 45.5 to 56.8 kg live weights corresponding to 21 to 26
weeks of age. In this study, maximum growth rate occurred in the pre-weaning
stage despite the fact that no creep feed was provided. Genotypic or management
differences may account for the discrepancy. It was observed in this study that
neither breed nor sex had any significant effect on ADFI per unit live weight
(Table 3). This suggests that the differences in ADFI found
among genotypes could be determined more by live weight than by genotype. Since
at similar weights, efficiency varied among genotypes, it implies that efficiency
of gain was much more genetically controlled among the treatment groups. These
results indicate that the major problem in rearing NI pigs is their poor feed
efficiency and this should guide future improvement strategies. When considered
against the fact that the local breed performed better at lower protein levels
than exotic breeds (Ilori, 1974; Bressani, 1974; Fetuga et al., 1977)
it is probable that the lower efficiencies of feed conversion observed in the
NI breed and the cross breed could have been due to the effect of the higher
protein content of the rations fed in this study. Fetuga et al. (1977)
had reported that protein levels higher than 16% crude protein reduces feed
efficiency in local breeds. Nevertheless, the live weights and average daily
gains of all breeds determined in this study were lower than those reported
in previous studies (Ilori, 1974; Fetuga et al., 1977; Ilori and Adepoju,
1980; Ilori et al., 1984). The reasons for the discrepancies were not
very clear. Since the NI breed has not been standardized and developed, a lot
of genotypic variations may occur across different agro-ecological zones. Although
the Large Whites performed below expectation in this study, results were similar
to that of Sonaiya (1981) who recorded mean live-weights of 10 kg and 13 kg
in local pigs at 4 and 7 months of age and 11 kg and 25 kg for the LW pigs at
similar ages. He also observed that over all ages, the females were heavier
than the males. Evidence suggests that a lot of inbreeding had taken place within
the LW flock in our research farm and the resultant inbreeding depression may
have affected the growth rate of LW pigs. The growth pattern (Fig.
1) was expected and the curves resemble the widely accepted standard sigmoid
growth curve of vertebrates (Hammonds, 1940). The superiority of the F1 crossbreed
over the N1 breed in live weight gain became apparent from the 18th week of
age, an indication of a different response to finishing. It may thus be argued
that the genes from the NI pigs dominated growth performance factors (traits),
while the accretion factors were principally controlled by genes inherited from
Generally, carcass lengths reported in this study (Table 5)
were similar to those observed by Fetuga et al. (1975). The dressing
percentages for NI males, LW males and LW females are lower than the figures
reported by Fetuga et al. (1975), but higher than that recorded by Sonaiya
(1986) for the NI pigs. Iloeje (1985) reported significant breed differences
in carcass characteristics. The similarity in rib-eye area between the male
and female LW pig was expected as many authors such as Sonaiya (1986), Iloeje
(1985) and Baas and Mabry (1998) reported a highly positive correlation between
rib eye area and carcass weight. The LW also had significantly higher back fat
thickness than the NI pigs (p<0.01) and this is in agreement with Adebambo
(1983) and Sonaiya (1986). The higher shoulder cut among the NI breed (Table
5), implies that there is a more prominent development of the fore quarters
compared to the LW, an indication that androgenic activity may be higher in
the NI breed. The higher percent head content in NI pigs supports this. The
significantly higher four lean cuts recorded by the NI male pig over the LW
counterpart implies that the NI pig had higher potential for lean cuts. These
results are contrary to those observed by Fetuga et al. (1975) who recorded
that the NI pigs has lower percent ham, shoulder, loin and the four lean cuts
but higher fat cuts. It is likely that the lower dressing percentage found among
the NI pigs in this work was due to its higher proportion of the head. The proportion
of internal organs was higher in NI pigs than in LW pigs. It is likely that
the activity of these organs per unit of the animals body weight was higher
in the NI than in LW breeds. Consequently, the NI breed may be metabolically
more a active animals. During the course of this experiment, it was observed
that they were behaviorally more active. Hyperactivity is also known to have
hormonal underpinnings (Gyton and Hall, 2000). It may be that their reduced
rate of live weight gain and feed efficiency were caused by this increased activity
and restlessness. It is thus advisable that selection for behavioral characteristics
of progenies be incorporated into the breeding programs aimed at improving the
growth, carcass and meat quality attributes of NI pigs.
Within the circumstance of this study, results of growth performance show that the LW breed gained more live weight than the NI pigs and cross breeding failed to improve growth performance in the F1 generation. However, better responses to finishing were observed among the crossbred pigs. Evidence from the literature suggests that a lower feeding regimen may have produced a different result. The NI pigs had superior carcass characteristics when compared to the LW pigs indicating that they possessed very useful traits, which can be exploited in carcass improvement programs.
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