GENETIC ANALYSIS OF GROWTH AND SOME REPRODUCTIVE TRAITS OF SHEEP OF NORTHERN NIGERIA AND THEIR CROSSES

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dc.contributor.authorIYIOLA-TUNJI, ADETUNJI OROYE
dc.date.accessioned2014-06-13T07:11:59Z
dc.date.available2014-06-13T07:11:59Z
dc.date.issued2012-09
dc.descriptionA THESIS SUBMITTED TO POSTGRADUATE SCHOOL, AHMADU BELLO UNIVERSITY, ZARIA. IN PARTIAL FULFILMENT FOR THE AWARD OF MASTERS OF SCIENCE IN THE DEPARTMENT OF ANIMAL SCIENCE AHMADU BELLO UNIVERSITY, ZARIA NIGERIA SEPTEMBER 2012en_US
dc.description.abstractA total of 65 Yankasa, 23 Uda and 16 Balami ewes were mated to 4 Yankasa, 3 Uda and 3 Balami rams in a diallel breeding pattern to produce 192 lambs that were used to genetically analyse growth and some reproductive traits. Weight records and linear body measurements were obtained from lambs at birth, 90-Day (weaning weight), 180- Day and 360-Day (yearling weight). Blood samples (5 ml) were collected from all the ewes and rams used for the study. The blood samples were subjected to cellulose acetate electrophoresis to obtain distinct bands of haemoglobin genotypes (AA, BB and AB). Daily growth of the lambs was calculated using average daily gain (ADG) and relative growth rate (RGR). The haemoglobin type HbAB was the most predominant in the studied population and allele A of the haemoglobin type was the most numerous. Breed and haemoglobin types had significant (P<0.05) effect on lamb weight. Crossbred lambs of Yankasa rams and Uda ewes (YK X UD) were the heaviest at birth. Pure Balami lambs were superior to all other lamb genotypes in body weight at 90 and 180-Day. The heaviest 360-Day weight (18.73±1.53 kg) was recorded for lambs of HbBB. The ADG and RGR of lambs were affected (P<0.05) by dam’s haemoglobin type, lamb genotype, type of birth and sex of lambs. Yankasa rams and ewes produced lambs with the shortest gestation lengths (151.84±0.23 days and 151.85±0.20 days, respectively). The highest litter size was recorded in UD X YK or BL X UD crosses. All the lamb genotypes had very high mortality from 180 to 360 days. However, there was no mortality recorded for BL X BL lambs from birth to 180 days. The HbBB genotype however had the highest percent mortality from 90 to 180-Day. The coefficients of phenotypic correlations between body weight and linear body measurements increased in proportion as Yankasa lambs grew from birth to 360-Day.Heritability estimates for body weight and some linear body measurements for Yankasa lambs were high at 180- Day (0.765±0.514) and 360-Day(0.805±0.961) indicating low effect of the environment on the traits in the studied population. Linear body measurements that considered volume of animal in terms of circumference (chest girth and loin girth) and body length (back length, neck length and height at wither) tended to give better accuracy of prediction of liveweight of lambs. Balami sheep (used as either sire or dam) expressed its superior genetic potential in terms of faster growth rate than Uda and Yankasa in the Northern Guinea Savannah agro-ecological zone. Selection for improved growth traits in the population of Yankasa sheep should be based on individual records of the lambs at 180-Day because of high heritability for 180-Day body weight of Yankasa lambs. Weighing chart and bands should be produced for all the sheep breeds considered on the basis of prediction equations.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/4866
dc.language.isoenen_US
dc.subjectGENETIC,en_US
dc.subjectANALYSIS,en_US
dc.subjectREPRODUCTIVE,en_US
dc.subjectNORTHERN,en_US
dc.subjectCROSSESen_US
dc.titleGENETIC ANALYSIS OF GROWTH AND SOME REPRODUCTIVE TRAITS OF SHEEP OF NORTHERN NIGERIA AND THEIR CROSSESen_US
dc.typeThesisen_US
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