parental haemoglobin

8/4/2019 Parental Haemoglobin

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EFFECT OF MATERNAL HAEMOGLOBIN VARIANT

ON PRE-WEANING GROWTH RATE OF SELECTEDBREEDS OF NIGERIAN SHEEP

Iyiola-Tunji, A.O.

Ahmadu Bello University,

Zaria, Nigeria


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Introduction Nigerian sheep breeds and their productive

potentials - Adu and Ngere (1979).

Limited attempts at improvement of Nigerian sheep

breeds.

Localized rearing of sheep in ecological zones

Osinowo and Adu, 1985.

Sheep breed characteristics and agro-ecologicical

location.

Sheep improvement through crossbreeding.


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Introduction Contd

Some adaptive and productive traits in sheep had

been linked to some variants of blood proteins.

Electrophoretic study of sheep haemoglobin types

showed that there are three main genotypes, which

are HbAA, HbBB and HbAB.

Variants of haemoglobin as genetic markers forselection of superior animals as parent of thenext generation.


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Objective of the study

This study was aimed at evaluating the

effect of maternal haemoglobin variant on

the pre-weaning growth rate of lambs in a

diallel crossbreeding involving Yankasa,

Uda and Balami.


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Materials and methods

Study location.

Sheep breed used.

Breeding pattern. Sire breed Dam breed

Yankasa Yankasa

Uda Uda

Balami Balami

Yankasa Uda

Yankasa Balami

Uda Yankasa

Uda Balami

Balami Yankasa

Balami Uda

Table 1: Diallel breeding pattern


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Materials and methods Contd

All lambs were singles.

Lambs identification.

Lambs weighed at birth and 2 weeks interval.

Statistical analysis- GLM Proc (SAS, 2003);

- Chi Square Proc.

Blood sample collection

Biochemical analysis of blood samples.


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Materials and methods Contd

Blood sample collection.

Sample analysis using cellulose acetate

electrophoresis.

B

A

Figure 1: Electrophoregram of haemoglobin variants

Anode

Cathode


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Results and discussion

Genotype frequency

Dam Hb Frequency Percent Sire Hb Frequency

AA 40 32.0 AA 0

BB 10 8.0 BB 0

AB 75 60.0 AB 10

Gene frequency

Dam Sire

A 0.62 A 50.0

B 0.38 B 50.0Hb = Haemoglobin; X2 = 50.8, P


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Allele A had the highest frequency (62%) in the

dam population.

This was in agreement with the report of

Akinyemi (2010) on Hb frequencies from similarbreeds of sheep.

Evans et al. (1958) had earlier suggested that

HbA has a selective advantage at higheraltitudes because it constitutes the mostcommon allele in highlands breeds of sheep.

Results and discussion Contd


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Contrastly, Salako et al. (2007) reported a higherfrequency of HbB in population of West AfricanDwarf sheep at low altitude in South-WestNigeria.



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Dam haemoglobin

Lamb genotype A B AB Total

YK X YK 15 (50.0) 5 (16.7) 10 (33.3) 30

UD X UD 0 (0.0) 0 (0.0) 10 (100.0) 10

BL X BL 0 (0.0) 2 (16.7) 10 (83.3) 12

YK X UD 10 (50.0) 0 (0.0) 10 (50.0) 20

YK X BL 0 (0.0) 0 (0.0) 5 (100.0) 5

UD X YK 0 (0.0) 0 (0.0) 10 (100.0) 10

UD X BL 10 (55.6) 3 (16.7) 5 (27.8) 18

BL X YK 5 (33.3) 0 (0.0) 10 (66.7) 15

BL X UD 0 (0.0) 0 (0.0) 5 (100.0) 5

Table 3: Cross-tabulation of lamb genotype by dam haemoglobin variant

Figures in parenthesis are expression of frequencies in percentages


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Dam haemoglobin variant

Trait AA BB AB Overall mean

GLT (days) 153.250.51b 153.900.89 b 152.200.28a 152.670.28

BWT (kg) 2.910.09 b 3.340.16 a 3.010.05 a 3.000.06

2WT (kg) 4.660.16 b 5.270.27 a 5.290.09 a 5.090.09

4WT (kg) 5.690.19 b 6.560.34 a 6.430.11 a 6.210.11

6WT (kg) 6.210.21 b 7.140.37 a 7.200.12 a 6.880.12

8WT (kg) 7.010.24 b 7.850.42 a 8.070.14 a 7.720.14

10WT (kg) 7.690.22 b 8.710.47 a 8.860.15 a 8.470.15

12WT (kg) 7.960.30 b 8.850.52 a 9.300.17 a 8.830.16abMeans across rows with different superscripts are significantly different (P


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The heterozygous form of haemoglobin (HbAB)in the population was probably more adapted tothe semi-arid condition of the study area than thehomozygous form HbAA.

This is clearly seen in better performance(in terms of pre-weaning growth rate) of the lamband the abundance of the genotype (HbAB) inthe population.


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Gootwine (1988) corroborated the result of thisstudy.

He stated that HbAB genonotype showed asignificant advantage over the other genotypesin both lamb and milk production.


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Conclusion

Haemoglobin genotype AB (HbAB) was thepredominant variant in the sheep population inNAPRI, Zaria, Nigeria.

HbAB dams had reduced gestation length andproduced lambs that performed outstandinglybetter than HbAA dams.


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Recommendation

The shorter gestation length and faster lambgrowth recorded for dams with HbAB should beconsidered and used in selection for a reduced

gestation length and improved growth rate oflambs in the population.


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parental haemoglobin

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