Department of Animal Science

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Department of Animal Science

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Open Access
All Flesh is Grass
(Obafemi Awolowo University Press, 1973) Adegbola, A.A
Livestock production in Nigeria is possible within the context of an overall improvement in all other aspects of agricultural development. Just as there is a need for grain surplus as a basis for development in pigs and poultry production; so there is a need for adequate soil management and water conservation practices to keep soils productive; good storage facilities and a cheap and efficient processing technique for crop and animal products, good roads and communications for fast transportation of highly perishable products and efficient distribution at low costs to consumers. There is a need to develop adequate organization for getting scientific information to the farmer. But above all, there is a need to guarantee adequate returns to farmers and to provide incentives like good water supply, adequate housing and rural electrification to farming communities. It is only in this context that we can truly develop the capacity necessary to convert all grass to flesh for the benefit of all in Nigeria.
Open Access
Determination of the Optimum Weight/Age and Composition of Broiler in Tropical Environment.
(Obafemi Awolowo University, 1984) Williams, Adebayo R.; Sonaiya, E. B.
In a study to determine optimum slaughtering age of broilers in Nigeria, 605 Cobb broilers were raised on floor pens, the birds were weighed weekly and 2 birds/pens were slaughtered fortnightly from six to sixteen weeks. Body weight, carcass weight, abdominal fat thickness and fat weight were measured. Internal body fat was determined by ether extraction of homogenized whole carcass less bone. Two way analysis of variance, simple and multiple regression and correlation analysis were carried out. Data on costs, revenue and net returns were obtained by questionnaire survey of poultry farms around Ile-Ife. The data were summarized and analysed graphically. Body weight, carcass weight, abdominal fat weight, abdominal fat weight as % live weight, abdominal fat thickness, total body fat, %total body fat, internal body fat and internal body fat as carcass weight were significantly affected by sex and age (P <0.01). Feed efficiency and feed conversion ratio were significantly affected by age (P <0.01).Highly significant correlations (P <0.01) were obtained among all body traits. Highly significant regression coefficients (P <0.01) were obtained by simple regression of internal body fat on carcass weight, body weight abdominal fat weight and fat thickness. Multiple regression analyses showed that, the regression was including fat thickness after abdominal fat weight and fat weight after carcass weight, Total body fat prediction can be reliably based on carcass weight abdominal fat weight for broilers between 6 - 16 weeks. Economics analysis revealed that profit is made when broilers till 16 weeks. When broilers are sold at a fixed price, the n point of slaughter is close to 12 weeks, but when broilers on weight basis, the optimum marketing age is just above and the physiological body data showed that fat deposition above after 12 weeks.
Open Access
Development of Protein-Source Feed Ingredients from Ruminal Content and Blood
(2015-04-15) Atunbi, Olufemi Adebayo
This study was designed to develop a protocol for the processing of blood and rumen content into protein-source feed ingredient for livestock, assess the microbial safety of the products, and determine the level of utilization of the products by broilers in order to provide readily available protein-rich feed. A preliminary survey of slaughter slab operations in Oyo, Ogbomoso and Ile-Ife was carried out before the commencement of the laboratory and feeding experiments to assess the mode of operation, type and volume of animals slaughtered, and how by-products, especially blood and rumen content, are disposed. Rumen content was collected from freshly slaughtered cattle in a plastic bowl. The rumen content was emptied into a woven sac and the water removed with the aid of a hydraulic press. The resulting rumen content was thereafter sifted through a 2mm sand sieve. The blood was prevented from clotting by adding 18 g common salt /kg of blood. Rumen content carried blood meal 1 (RCCBMI) was produced by mixing sifted rumen content and blood in the ratio 4:3 w/w and sun-dried to a moisture content of 10.55%. Rumen content carried blood meal 2 (RCCBM2) was obtained by mixing RCCBMl and blood at a ratio of 2:3 wlw and sun-dried to a moisture content of 10.9%. Proximate and amino acid composition, energy content, and microbiological status of RCCBM1 and RCCBM2 were determined. Nutrient bioavailability trials with RCCBMl and RCCBM2 yielded apparent and true nitrogen retained (ANR and TNR) of 0.7 g, 1.26 g and 0.84 g. 1.40 g, respectively, apparent and true metabolizable energy values (AME and TME) 1.9231 kcal/g, 2.3883 kcal/g for RCCBMI and 2.184 kcal/g, 2.737 kcal/g for RCCBM2 and apparent and true metabolizable energy values corrected for nitrogen (AMEn and TMEn) values of 1.8045 kcal/g, 2.1625 kcal/g and 2.082 kcal/g, 2.464 kcal/g for RCCBMl and RCCBM2 respectively. Fourteen-day-old broilers were used in growth trials for 35 days with RCCBM2 at 0%, 5%, 10%, and 15% levels of inclusion in starter and finisher diets in a completely randomized experimental design. Data were analyzed using the 2-way analysis of variance procedure to compare the treatment groups in nutrient bioavailability trials and growth performance trials with broiler chickens. The results showed that the ANR, TNR, AME, AMEn, TME and TMEn were significantly (f=2.66, 3.32, 2.30, 2.76, respectively, P<0.05) higher for birds fed RCCBM2 than for birds fed RCCBM1. The average final body weight and average daily weight gain were significantly (f =4.67, 4.05, respectively, P<0.05) higher for birds on treatment with 10% level of inclusion RCCBM2 than for those on 0, 5, and 15%. Total viable microbial counts of 6.9 x105 cfu/g and 5.8x104 cfu/g for RCCBM1 and RCCBM2 respectively, did not reach the critical safe level of l x l05 cfu/g after 60 days of storage. The study concluded that a simple protocol was successfully developed for the processing of blood and rumen content into protein-source feed ingredients (RCCBMI and RCCBM2). These were microbiologically safe and RCCBM2 can be fed at 10% level of inclusion in broiler chicken starter and finisher diets.
Unknown
Digestability and Feed Intake Studies with Pregnant and Lactating West African Dwarf Goats.
(Obafemi Awolowo University, 1987) Adenuga, Michael Kehinde; Ademosun, A. A.
The effect of pregnancy and lactation on digestibility and voluntary intake of feed was studied with a total of 15 female West African dwarf goats fed alfalfa pellets ad libitum. The effect of pregnancy and lactation on eating and rumination times was also studied in eight out of these animals. The animals were individually penned and fed ad libitum throughout the experiment. The apparent digestibility coefficient of the feed was determined during pregnancy and lactation when the animals were kept in metabolism crates for 14 days adaptation and seven days collection period. The voluntary feed intake and liveweight data were collected weekly while rumination and eating time’s data were collected daily by observing the jaw motions of the animals during pregnancy and lactation periods. Data were subjected to statistical analyses using the analysis of variance (ANOVA), students’ t-test, Kruskal-Wallis 1-way ANOVA and Wilcoxon Matched pairs signed rank test. The pregnant does had a higher liveweight (23.5 kg) and higher rate of weight gain than the non-pregnant ones (21.48kg) (P<0.05). The reverse was the case during lactation. The lactating does weighed 23.62Kg while the non-lactatin does weighed 25.66Kg. The apparent differences in voluntary feed intake (VFI) and apparent dry matter (DM) digestibility between pregnant (764.3g/anim./day and 54%) and non-pregnant does (666.5g/anim./day and 55%) were not significant. During lactation, VFI increased from parturition until the seventh week in lactation. Dry matter intake declined afterwards. However, the difference observed for the apparent DM digestibility between lactating (53%) and non-lactating does (5%) was not significant (P>0.05). Times spent eating and ruminating by the pregnant does (356.1 min/day and 495.2 min day) were significantly higher than those of non-pregnant ones (253.6min/day and 423.7min/day), but the time spent by the lactating does on eating alone (363.1min/day) was significantly higher than that of non-lactating does (231.3min/day) (P<0.05). Models used to describe feed intake during pregnancy and lactation could explain 68.2% and 85.3% of the variations in intake respectively. This showed that feed intake during pregnancy may be difficult to predict than during lactation.
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Effect of Age at Breeding on Reproduction in Local Sheep
(Faculty of Agriculture, University of Ife, 1979) Chiboka, O.
Forty nulliparous West African Dwarf and Permer X West African Dwarf crossbred ewes were used in two separate experiments to study the effect of eight breeding groups (6, 7, 8, 9, 10, 11, 12 and 13 months) on weight at breeding, gestation length, frequency of twinning, birth weight, frequency of stillborn, placenta weight, frequency of milk ejection and weaning weight. In the first experiment, four out of five West African Dwarf ewes in the six month age group showed heat. After breeding the estrous ewes, only one appeared pregnant but later returned to heat about 57 days post breeding. All the ewe in the 7 month age group showed heat and after breeding only one was pregnant which later aborted about 131 days post breeding. All West African Dwarf ewes bred between the ages of 8 - 13 months were pregnant and successfully went to term. There were significant differences in breeding weight and birth weight among the ewes in age group 8 - 13 months. On the whole breeding at 8 months of age appeared to have the same effect as breeding at a later age. Age and breeding weight were significantly correlated. One out of thirty fetuses (one fetus from group 10) was stillborn and there was 100% milk ejection. In the second experiment, three out of five Permer X WAD ewes assigned to the 6 month age group showed heat but after breeding none became pregnant. All ewes in 7 month age group showed heat but after breeding all showed heat regularly except two which later returned to heat 43 and 47 days (respectively) post breeding. All Permer x WAS ewes bred between the ages 8 - 13 months were pregnant and successfully went to term. Of the age groups that went to term, there was no difference amongst them in all the variables studied except in placenta weight. There was no significant correlation between age and anyone of the variables measured.
Open Access
The Effect of Dietary Protein and Palm Oil on Performance, Age, and Weight at Puberty of Indigenous Pigs in Nigeria
(Faculty of Agriculture, University of Ife, 1984) Ilori, J. O.; Yusuph, N. A.; Somade, B.
Forty-eight indigenous pigs averaging 89.6 days in age and 12.9 kg body weight were used in a 4 x 2 factorial experiment. Dietary treatments were 15 and 18% levels of protein and 0, 2, 4 and 8% levels of palm oil, added to each protein level. The diets were fed ad libitum and water was available at all times until the onset of puberty (first estrus). Increasing the protein content of the diet gave significantly higher rates and efficiency of gain in pigs. Increasing the palm oil content of the basal 15 or 18% protein diet improved rate and efficiency of gain up to 4% palm oil level in the 18% protein diet but only up to 2% palm oil level in the 15% protein diet, indicating a need for increased dietary palm oil/energy with increased protein intake to maintain conversion efficiency. Increasing the palm oil content of the basal 15% or 18% protein diet improved feed consumption at all palm oil levels in the 15% protein diets but only up to 4% palm oil level, in the 18% protein diets. Increasing the protein content of the diet resulted in heavier and younger pigs at puberty. Increasing the palm oil content of a basal 15% or 18% protein diet did not appreciably affect big weights at puberty (range 33.3 to 36.1 kg) unlike age of pigs at puberty which was significantly reduced (range 152.3 to 167.5 days) by increasing dietary palm oil levels.
Open Access
The Effect of Environment on Reproductive Performance of Dairy Cattle in South Western Nigeria
(Faculty of Agriculture, University of Ife, 1982) Somade, B.
The effect of environment on the reproductive performance of 50 Holstein cows at the Iwo Road Dairy Farm of Oyo State, Nigeria, was evaluated by summarising and analysing data collected on the cows over a seven year period (January 1970 to December 1976).Two main seasons were discernible from the rainfall and temperature data: (i) the dry season with a mean rainfall of 36mm and mean maximum and minimum temperatures of 31.6oC and 22.3oC respective1y;and (ii) the wet season with a mean rainfall of 176 mm and mean maximum and minimum temperatures of 29.s0c and 22.7% respectively. These seasonal variations adversely affected reproductive performance. Data collected for the dry and wet seasons respectively were: services per conception, 3.7.and 2.5; number of conceptions, 35 and 121; first oestrus after calving, 61 and 50;days from first service to conception, 64 and 52; and number of claves born, 53 and 91.
Unknown
The Effect of Feeding Cassava Root Meal on the Performance, Carcass Characteristics, Serum and Urinary Thiocyanate Concentration of Fryer Rabbits
(Faculty of Agriculture, University of Ife, 1980) Eshiett, N. O.; Omole, T. A.; Ademosun, A. A.
Thirty-two, five-weeks old New Zealand White fryer rabbits were fed four diets containing, 0, 15, 30 or 45% cassava root meal (CRM) in an experiment designed to investigate the utilization of CRM by fryer rabbits. The levels of CRM fed did not adversely affect the growth rate of the rabbits, but those fed 0 and 15% CRM diets consumed significantly less (P < 0.05) feed than those on the 45% CRM diets. Similarly, rabbits fed the control (0% CRM) diet utilized their feed better (P < 0.05) than those on the CRM diets. The 15 and 30% CRM diets were utilized similarly but were superior to the 45% CRM. The serum thiocyanate concentration of rabbits fed the 0, 15, 30 and 45% CRM diets were 1.59, 1.72, 1.66 and 1.76mg/100ml respectively. Corresponding values for urine thiocyanate were 2.94, 3.15, 3.15 and 3.21mg/100ml. These values were however not significantly different. Carcass quality was similar across treatments.
Open Access
The Effect of Prolonged Feeding of Stylosanthes guyanensis Meal on Laying Performance, Egg Quality and Hatchability
(Faculty of Agriculture, University of Ife, 1979) Onwudike, O. C.; Adegbola, A. A.
The utilization of increasing levels of Stylosanthes guyanensis meal (stylo meal) by laying chickens feed for a period of nine months and the effect of increasing levels of vitamin A on the hatchability of eggs were studied using Single Comb White Leghorn birds. The feeding of stylo meal to laying birds lengthened the time taken by the birds to get to peak production. There was no significant effect on the average hen-day production percentage following the feeding of up to 20% stylo meal. The control diet in which there was no stylo meal however had a better production rate than any of the other diets. The feeding of stylo meal increased egg riboflavin content, egg hatchability and yold cholesterol level and depressed serum cholesterol level. The improved egg hatchability observed in this study could not be related entirely to the improved vitamin A status of the diets with the addition of stylo meal. It is suggested that the utilization of higher levels of stylo meal could be improved by a better amino acid balance and pelleting of the rations.
Open Access
Effect of Some Non-genetic Factors on Growth Rate of Tropical Cattle in Nigeria
(Faculty of Agriculture, University of Ife, 1982) Akinokun, O.
Data on 1,962 bulls purchased on cattle routes, and fed on pasture for slaughter were analysed for effects of period of start of feeding, initial weight and age at the start of grazing. Results showed that period of start of grazing had a significant effect, with bulls coming in late in the rainy and early in the dry seasons showing superior growth rate over the first three months and six months, compared with those brought in at other times. Effects of age and weight at time of start of feeding were also highly significant. Least squares means for growth rate over the first three months and the first six months were 130g and 220g respectively. It is suggested that improved pasture management, and supplementary feeding particularly in the dry and early rainy seasons are essential for improvement of growth performance.
Open Access
The Effect of Varying Dietary Protein and Antibiotic Levels on the Performance of Weanling Local Pigs
(Faculty of Agriculture, University of Ife, 1980) Ilori, J. O.; Adepoju, A.
Two feeding trials were carried out to examine the effect of graded dietary 'levels of protein and antibiotics on the performance of weanling local pigs. In the first trial, 5 groups of 12 pigs each, were fed a 16% protein diet containing respectively, 5 graded levels of strepcillin (0, 25, 50, 75,100gltonne of diet). In the second trial, 9 groups of 8 pigs each, were fed 9 different diets respectively, in a 3 x 3 factorial arrangement of treatments (3 protein levels of 12, 15, 18%, 3 strepcillin levels of 0, 50, 75gltonne). Daily gains, feed efficiency, scouring incidence, dry matter and crude protein digestibilities were recorded. Increasing dietary strepcillin improved (P < .05) growth rate and feed efficiency. The improvement plateaued at 75g strepcillin/tonne diet. A non significant (P > .05) protein x antibiotic interaction effect was observed on pig performance. Feeding antibiotics reduced scouring incidence, but had no significant effect on nutrient digestibilities.
Open Access
Effects of Age of Cow at First calving, Period of Calving and Calving Sequence on Calving Interval of N’dama and Keteku Cattle, and their Crosses in Southwestern Nigeria
(Faculty of Agriculture, University of Ife, 1982) Akinokun, O.
Calving records of N'darna and Keteku cows on range in the humid tropical environment of southwestern Nigeria were analysed to determine the effects of cow age at first calving, period of calving and calving sequence on length of calving intervals. Cow age at first calving and calving sequence significantly affected calving intervals (P < .01). Heifers calving for the first time at 3.6 - 4 years had an average calving interval of 511 days while heifers calving for the first time before 3.6 years had intervals that were 36 days longer. Those calving for the first time at over four years had average calving intervals that were shorter by 73 days. There was a progressive decrease in length of calving interval as calving sequence increased. Period of calving had no significant effect on length of calving interval.
Open Access
Efficacy of Aqueous Extract of Pawpaw (Carica Papaya) Leaf in the Control of Coccidiosis in Chicken
(2015-04-16) Babalola, Peter Olufemi
The study investigated the potency of aqueous extract of pawpaw leaf compared with a conventional anticoccidial drug, sulphamethazine sodium, in the treatment of coccidial infection in chicken. This was necessitated by the need to get an effective, readily available and comparatively cheaper drug to control coccidiosis. Oocysts of coccidia (Eimeria species) were isolated from the intestine and caeca of infected chickens and subsequently cultured in 2.5% potassium dichromate solution. Three hundred, four weeks old cockerel chicks were used for this study. The experimental chicks were divided into five treatments of twenty each and the experiment was replicated thrice. Each group was infected with sporulated oocvsts of the cultured Eimeria species through drinking water. The fresh pawpaw (Carica papaya) leaves were boiled (50 g / litre of water) for fifteen minutes to extract the juice and the supernatant was allowed to cool. There was no drug or extract administration to Treatment 1 chicks, the leaf extract was injected intramuscularly at the rate of 2 ml, 3 ml and 4 ml per kilogramme body weight to Treatments 2, 3 and 4 chicks respectively daily for four consecutive days. Sulphamethazine sodium, an anticoccidial drug, was injected at 0.5 ml per kg body weight to Treatment 5 for four days also. The feed intake, weight gain, mortality, consistency of faecal droppings, morbidity and abnormal chicks reaction due to the injection of the leaf extract were investigated. The results of the study showed that there were significant differences in the feed intake and weight gain over time (F = 3.84, P<0.05) between the different doses of pawpaw extract and the sulphamethazine sodium with the latter recording highest values for feed intake and weight gain respectively (87.9 g, 296 g). On the other hand, oocvsts discharges per gramme of faeces, percentage mortality and percentage morbidity were lowest for sulpha drug treated chicks (2.3, 0% and 3.3% respectively) (F = 3.84, P < 0.05). There was a great reduction in the observed severity of the lesions in the intestine and caeca on post mortem examination in favour of sulpha treated chicks. Nonetheless, higher values were observed in the average feed intake/day (82.1 g) and total weight gain per chicken (230 g), lower values in the average number of oocysts voided per gramme of faeces (2.3), percentage mortality (31.7%) and percentage morbidity (63.3%) for birds in Treatment 4 than the other extract or control groups. The extract was found to have a short-lasting itchy reaction on the chicks. It was concluded that extract of Carica papaya leaf can be substituted for sulpha drugs at the experimented dosage rates though it was found to be less effective as the conventional sulpha drugs. However, more concentrated experimented leaf extract dose proved more effective in controlling coccidiosis than the less concentrated doses considering the parameters investigated.
Open Access
Energy Flux and Animal Products
(Obafemi Awolowo University Press, 1998-06-09) Emmanuel, B. S.
The production of food is a process of energy transformation - changing energy from, an inedible into an edible form: Different foods vary .in the energy required to .make them fully edible. Energy use in food production has been increasing faster than its use in many other sectors of the world economy and has become an overriding factor in food production distribution and consumption. Today, the source and use of energy are key issues in every area of human endeavor Agriculture is unique 'because one of its-major energy sources is the sun..
Open Access
An Evaluation of Damage to Bovine Spermatozoa during Processing, Freezing and Thawing II. Effect on Motility, Percentage Live and Ultrastructure of Spermatozoa
(Faculty of Agriculture, University of Ife, 1979) Somade, B.; King, G. J.; Macpherson, J. W.
Thirty semen samples from five bulls were processed and frozen. Each ejaculate was evaluated for percent progressive motility, percent live spermatozoa and percentage of heads, tails and mid-pieces with intact plasma membrane after collections, after extension and cooling just before freezing and after thawing. The greatest decrease in both motility and percent live spermatozoa occurred before freezing. More spermatozoa heads were damaged at each phase of processing for freezing than mid-pieces and tails and there was also a greater number of damaged spermatozoa before freezing than after freezing and thawing.
Open Access
An Evaluation of Damage to Bovine Spermatozoa during Processing, Freezing and Thawing. I Leakage of Glutamic-oxaloactetic transaminase [GOT] from Spermatozoa
(Faculty of Agriculture, University of Ife, 1979) Somade, B.; King, G. J.; Machperson, J. W.
The activity of glutamic-oxaloacetic transaminase (GOT) in the seminal plasma of thirty ejaculates after collection; after extension, cooling and equilibration just before freezing; and after freezing and thawing were determined. After correction for the reduction in the activity of GOT caused by the extender and low temperatures the activity of the enzyme was higher (P 0.05) in post thaw semen than in either ejaculated or equilibrated semen just before freezing. However, the pre-freeze leakage of GOT from spermatozoa was similar to the leakage caused by freezing and thawing. The significance of these findings in relation to the use, of GOT activity in seminal plasma as an index of spermatozoa damage were discussed.
Open Access
Evaluation of the Nutritive Value of the African Giant Land Snail, Archachatina (Calachatina).
(Obafemi Awolowo University, 1987) Imevbore, Emmanuel Abayomi
In order to assess the nutritive value of the African giant land Snail (Archachatina marginata), a comparison between its meat and some conventional sources of animal protein - beef, broiler meat, mutton, pork, goat meat and two types of fish (Tilapia macrocephala and Clarias lazera) was made. The proximate composition, fatty acid, amino acid and mineral analyses, as well as cholesterol content of the samples were used as criteria for comparison. With a protein content of 88.37%, snail meat compared favourably with the conventional animal protein sources, whose protein values ranged from 82% to 93% of the dry sample. It was however low in total fat content (1.64%), percent saturated fatty acids (28.71%) and cholesterol content (20.28 mg/100g sample) when compared with each of the other samples. While its amino acid profile was generally similar to those of the samples tested along with it, mineral analysis showed that snail meat is a rich source of minerals, particularly calcium and phosphorus with values of 185.70 mg/100g and 61.24mg/ 100g dry sample respectively. The amount of these minerals in the others, for example, beef sample (53.00 mg/100g calcium and 24.05 mg/100g phosphorus) is much lower than is present in Snail meat. By virtue of its chemical composition, the meat of the Archachatina marginata has some potential as a source of essential nutrients. It may also be useful medically, since it appears to possess certain medicinal properties.
Open Access
Factors Influencing Mineral Content and Utilization of Tropical Forages by Ruminants.
(Obafemi Awolowo University, 1985) Kabaija, Ephraim M.; Smith, O. B.
A study was conducted to evaluate the effect of season (wet/dry) and age of regrowth (3,6,9,12 weeks) on the mineral contents of two common browses - Gliricidia and Leucaena. Another study evaluated effect of season, age of regrowth (2,4,6,8, 10,12 weeks) and fertilizer application (with/ without) on the mineral contents of Guinea grass and giant star grass. With both browses and grasses, significant age of regrowth by season effects were observed, with K and P contents declining with age while Na, Ca and Fe contents increased, during either season. Fertilizer application in the grasses resulted in increased content of K and P while Ca and Mg contents declined. The herbage K, P and Cu contents were lower during the dry season while Zn, Fe and Mn contents were higher. Despite these fluctuations, the forages contained adequate amounts of all minerals for livestock requirements except for P, Na, Zn and Cu which were marginal to deficient. A subsequent study showed that P supplementation to lambs fed on Guinea grass hay improved both their performance and bone quality. Since these forages rapidly become fibrous, the effect of fiber level on mineral utilization was evaluated in 3 studies. Using the nylon bag technique, a higher rumen mineral release of 22.0% was obtained in 6 week old forage regrowth compared to that of 14.3% got in the more fibrous 12-week old regrowth. Mineral availability and absorption declined (P<0.01) as dietary fiber level increased. The results indicated dietary fiber to be one of the main factors influencing utilization of minerals by ruminants. Thus particular attention should be paid to mineral status of ruminants when feedstuffs such as standing hays or crop residues with high fiber content are fed.
Open Access
Genetic and Environmental Aspect of Preweaning Weight Gain of Pigs in South Western Nigeria
(Faculty of Agriculture, University of Ife, 1980) Leigh, A. O.
Data recorded at Fasola Stock Farm for 451 litters and involving 66 boars and 4 breeds of pigs were analysed to investigate the environmental and genetic factors causing variation in preweaning weight gains of pigs. Two specific traits - average pig weight gain from birth to weaning (PPWG), and litter weight gain from birth to weaning (LPWG) were studied. The two traits did not show significant effects of breed, parity of dam, season or interaction (P>. 05). Only PPWG showed highly significant effects of year (P < .05). However, litter size at birth and at eight weeks, and average pig weight at birth had significant influence on both traits. Estimates of heritability based on paternal half-sib correlation were 0.19 to 0.15 and 0.49 to 0.20 for PPWG and LPWG respectively. Both the phenotypic and genetic correlations between the two traits were high and positive (rP = .75 and rG = .98). It is suggested that weight gain from birth to weaning at 8 weeks instead of weaning weight per se should be used as criterion for making initial selections of future breeders.
Open Access
Genotype x environment interactions in an exotic commercial egg strain and the local chicken of Nigeria
(Faculty of Agriculture, University of Ife, 1979) Osu, A.; Dettmers, A.
Six hatches of the Apollo, a commercial egg strain of chicken imported from the United Kingdom at day old and the Local chicken hatched from eggs collected all over Southwestern Nigeria were reared under modem brooding, feeding and management conditions to study genotype, x environment interaction. Body weight, egg weight and egg production from first egg to eight months of production were recorded for each hen. Analyses of variance showed that there were significant breed x hatch interactions for age at sexual maturity, egg weight from the third month of production. and four and eight month egg production. Body weight at 12 and 20 weeks of age, weight of first egg and egg weight at first month of production did not show significant breed 5 hatch interaction effects. The results show that locally adapted breeds and strains are required, in view of large environmental differences between the temperate and tropical climates.