Browsing by Author "Raghavan, K C"

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Construction and comparison of the efficiency of different selection indices for malabari goats
(Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 2009) Rani Alex; Raghavan, K C
Genetic and phenotypic variations of geographically different goat populations of Kerala
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2007) Jimcy Joseph; Raghavan, K C
Genetic diversity of four geographically different goat populations in Trivandrum, Kottayam, Thrissur and Kozhikode districts in Kerala was analysed based on physical, biometrical traits and microsatellite markers. Based on physical traits, the populations were not very distinct and uniformity was seen with respect to coat colour, horn pattern, presence or absence of tassels or beard and hair pattern. The animals were predominantly horned and short haired with coat colour of white or a combination of white with either black or brown. Majority of animals did not possess tassels or beard. The biometrical traits observed in the present study were body measurements, peak yield and prolificacy. Body weight of adult female goats was predicted using the regression equation based on the power function of chest girth. It was shown that the animals of Trivandrum district had higher values for almost all body measurements and predicted body weight, while the Thrissur population had lowest values for these growth traits. Animals of Kottayam and Kozhikode came in between. Percentage of multiple births was also higher in Trivandrum goat population (68) compared to other populations indicating high prolificacy. Highest peak yield was recorded for Kottayam goat population. Discriminant analysis based on morphometric measurements revealed that the most discriminative variables were head width and body length, followed by shin circumference and rump length. Mahalanobis distance calculated based on morphometric traits indicated that Thrissur and Trivandrum populations were more distant, while least distance was observed between Kottayam and Kozhikode. Discriminant analysis based on body weight, peak yield and prolificacy revealed that only body weight and peak yield variables have significant discriminative capacity. Trivandrum, Kottayam and Kozhikode populations were grouped together in one cluster based on the distance value. Thrissur population was distant from all other populations. Microsatellite analysis revealed that all the five loci were highly polymorphic with five to nineteen alleles in different populations. The total number of alleles, the mean number of alleles per locus, mean heterozygosity and mean polymorphic information content were 51, 10.2, 0.8201 and 0.8104, respectively. The values indicate that the markers can be successfully used to study the variations existing in the populations. Based on Nei’s genetic distance Thrissur and Trivandrum population were grouped together first and then with Kozhikode population, while the Kottayam population formed a unique branch in dendrogram. Unrelated distance values produced by quantitative and molecular measures of variation may be attributed in part to the environmental influences and local selection pressures. Though use of more number of markers may possibly explain the variation encountered in these traits, the present investigation reveals that selection within each population for traits of economic importance like body weight and milk production is the best method to improve the performance of goats of Kerala.
Genetic factors influencing feed efficiency in pure and crossbred broiler rabbits
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2000) Kasiviswanathan, D; Raghavan, K C
An experiment was carried out to study the genetic and non- genetic factors influencing feed efficiency (feed g/gain g) in broiler rabbits viz. New Zealand White (NZW), Soviet Chinchilla (SC) and SC x NZW crossbreds (CB). The non-genetic factors induded were sex, litter size at birth, season and year of birth. The data pertaining to fortnightly body weight from four to 12 weeks of age, feed efficiency (FE) and daily gain (OG) were subjected to least squares analysis. Breed had significant effect on body weights at all ages. NZW had the least body weights through out the experiment and SC and CB did not differ significantly at market age of 12 weeks. Overall daily gain was not affected by breed while FE was significantly (P.:: 0.01) influenced by breed. CB had the highest FE followed by SC and NZW rabbits. Dressing percentage was highest (48.91) for CB compared to NZW and SC. Crossbred rabbits exhibited a heterosis of 1.6 and 9.3 per cent for iz" week body weight and FE respectively over the pure bred parents. Sex was not a source of variation for any trait except for body weight at weaning (four weeks). Litter size at birth had significant effect on body weights at all ages but had no effect on overall OG and FE. Season and year of birth influenced body weights at early ages only and had no effect on overall OG and FE. Estimates of heritability by sire + dam component of variance were moderate to high for body weights at different ages, high for DG and not different from zero for FE. Phenotypic correlations among body weights at different ages were high and significant and genetic correlation estimates were higher in magnitude for later ages. Phenotypic and genetic correlation of FE with twelfth week body weight and DG were near to zero. The present study indicated that breed is a significant source of variation affecting body weight from four to 12 weeks of age and FE in during period. CB rabbits though did not differ from SC for 1 z" week body weight excelled the pure breeds when FE and dressing percentage are considered. In monetary terms CB rabbits are found to be superior by 1.6 and 1.43 times over NZW and SC rabbits. So, crossbreeding of SC and NZW rabbits is advocated for profitable commercial broiler rabbit production.
Genetic polymorphism of major histocompatibility complex class II genes
(Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 2010) Remya John, V; Raghavan, K C
The study was conducted in 85 Malabari and 30 Attappady Black goats to analyze the PCR-RFLP polymorphism and the sequences of Major Histocompatibility Complex class II DRB and DQA2 genes. The analysis of DRB/TaqI polymorphism in Malabari and Attappady Black breeds of goats showed similar restriction patterns in both breeds with no significant changes in allele frequencies. It was also found that all the three genotypes had an equal survival capacity with respect to DRB/TaqI site as both the populations were under were under Hardy-Weinberg equilibrium. The analysis of DRB/ PstI polymorphism revealed existence of two digestion patterns (PP, Pp). The ‘pp’ pattern was absent in both Malabari and Attappady Black goats probably due to the lethal effect of ‘pp’ genotype which has prevented the survival of that genotype in the studied population. This natural selective force acting against ‘pp’ genotype resulted in significant changes in the expected genotypic frequencies and the populations were found to be not in Hardy-Weinberg equilibrium. The analysis of DQA2/EcoRV polymorphism in Malabari and Attappady Black goat populations revealed existence of all the three possible restriction patterns with a clear heterozygotic advantage (genotype frequency of 0.79 for ‘Ee’ in Malabari goats) which is expected to be due to existence of duplicate copies of DQA2 gene. The sequencing of the DRB gene second exon form Malabari and Attappady Black goats revealed four different DRB alleles having 285 bp each and were more similar to Capra aegagrus (98 to 99 percent) DRB alleles in BLASTn analysis. The sequencing of the DQA2 gene second exon and the flanking intronic sequences form Malabari and Attappady Black goats revealed four different alleles, three of which were having 304 bp each and the fourth one having 300 bp. The sequencing revealed the base changes responsible for the presence or absence of TaqI, PstI and EcoRV restriction sites in Malabari and Attappady Black goats. The 93 and 82 amino acid compositions of DRB and DQA2 second exons revealed amino acid replacements at 23 and 21 positions respectively, many of which are present at the antigen binding region and hence affect peptide specificity. PstI genotypes significantly affected the Ig level in goats and the heterozygotic genotype was found to have higher efficiency in antigen processing. The present study has helped to understand the variations existing in the second exon of DRB and DQA2 loci in Malabari and Attapady Black breeds of goats which has a role in the disease resistance and immunity.
Growth and survivability of GH/Msp I genotypes in malabari goats
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2004) Bindu Mathew; Raghavan, K C
etc. Growth hormone gene, due to its essential role in lactation and growth processes, is a perfect candidate marker associated with somatotropic axis. Selection of animals based on the growth hormone genotypes can be introduced in the animal husbandry sector for better production. The present investigation was undertaken to study the growth and survivability of GH/MspI genotypes in Malabari goats at different centers of Badagara, Thalassery, Thanur as well as Malabari conservation unit, Regional Agricultural Research Station, Pilicode. DNA was isolated from 32 bucks, 241 does mated to those bucks and 297 of their progeny using phenol - chloroform extraction method. A 768-bp fragment from third exon to fifth exon containing the polymorphic Msp1 site was amplified well using bovine primers, indicating species homology. The amplified product on digestion with the Msp1 enzyme revealed the GH/Msp1 (+) and (-) alleles. The percentage of incidence of (+/-) genotype was 61.76 and that of (+/+) genotype was 38.24. None of the animals typed were of the GH/Msp1 (-/-) genotype. The genotype frequencies of bucks and does were consistent with the general population. In the specific heterozygous mating (+/- x +/-), 28 per cent of the progenies were (+/+) homozygotes and the rest 72 per cent were heterozygotes (+/-). Early embryonic mortality was not found to be a cause for the absence of the GH/Msp1 -/- genotype as the kidding percentage in heterozygous mating were not different from other types of matings. There was no relationship between growth upto six months of age and GH/Msp1 genotypes. The study confirms a strong heterozygotic advantage for the GH/Msp1 +/- genotype and also the absence of GH/Msp1 -/- genotype in Malabari goats. Presence of duplicate copies of the growth hormone gene in goats may be a possible reason for the above results.
Polymorphism of ovine fecundity gene linked microsatellite markers in malabari goats
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2006) Seena, T X; Raghavan, K C
The objective of the present study was to explore the polymorphism of ovine fecundity gene linked microsatellite markers in Malabari goats. Malabari goats are one of the most prolific breeds in India. The microsatellite markers OarAE101, BMS2508 and BM1329 linked to the Booroola gene (FecB) and the microsatellite markers TGLA54 and TGLA68 linked to Inverdale (FecX1) gene in sheep were selected for the study. The DNA samples from 120 Malabari goats which had given birth to singles, twins, triplets and quadruplets in the second and subsequent parities were utilized for the study. DNA was isolated by phenol chloroform extraction procedure with some modifications. The DNA samples were amplified by PCR using the radioactively labeled microsatellite primers. The amplified products were resolved by polyacrylamide gel electrophoresis followed by autoradiography. The genotypes of animals were determined for each microsatellite loci by comparing the sizes of alleles with M13 phage DNA sequencing ladder. The microsatellite markers OarAE101, BMS2508 and TGLA54 were found to be monomorphic in the population under study. The microsatellite markers BM1329 and TGLA68 were found to be highly polymorphic in Malabari goats. A total of 15 alleles with 167-195 bp for the locus BM1329 and 8 alleles with a size range of 98-114 bp were observed for the locus TGLA68. The total number of genotypes observed was 34 for BM1329 locus and 12 for TGLA68 locus. Heterozygosity of 0.8660 for the locus BM1329 and 0.8024 for the locus TGLA68 were observed. The polymorphic information content (PIC) computed was 0.8526 and 0.7823 for the loci BM1329 and TGLA68 respectively. A significant difference in the alleles 181bp and 191 bp (P≤0.01) and the alleles 179 bp and 185 bp (P≤0.05) and the genotype 177/191 (P≤0.01) for the locus BM1329 were found in different types of births. The genotype 175/185 of the microsatellite marker BM1329 was found to be significantly related to a higher litter size when compared to the mean litter size of the population in Malabari goats (P≤0.01). The allele 104 bp of the locus TGLA68 was found to be significantly different in different types of births (P≤0.01). The highest frequency (0.4545) was observed in triplets followed by twins (0.2177) and singles (0.1847). The genotype 104/106 was found to be significantly different in different types of birth with triplets having a frequency of (0.4545), followed by singles (0.1087) and twins (0.0333). The season of birth had no significant effect on the type of birth and number of kidding in Malabari goats. Identification and selection of individuals that carry the alleles and genotypes associated with high prolificacy is possible in Malabari goats based on the above result. So new breeding strategies involving selection for high prolificacy can maximize the net profit of farmers. This study has brought to light important information improving the reproductive performance of Malabari goats by marker assisted selection.
Studies on certain genetic and nongenetic factors affecting birth weight and growth rate malabari and crossbred goats
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1980) Raghavan, K C; Krishnan Nair, B R
The data on 1227 kids belonging to Malabari (309) Saanen x Malabari (389) and Alpine x Malabari (309) genetic groups born and brought up at the All India co – ordinated Research Project on Coats, Kerala Agricultural University, Mannuthy during the period from April 1974 to March 1979 were utilised to study the effects of various genetic and non genetic factors on body weight at different ages. Crossbred goats, S x M and A X M, registered higher weights at birth, at one month, at four months and at one year than the local Malabari goats. District sexual dimorphism in body weights at different ages could be observed in crossbred goats. Litter size significantly affected birth weight and weight at one month. Sason of birth had only non significant influence on weights at birth and that at one month, though the effect was significant on 4 month’s and one year weights. Even though the effect of gestation length undergone by kids was a significant source of variation for weights at birth alone in Saanen x Malabari and Alpine x Malabari kids, the same had significant effect on body weights at birth and at one month in Malabari. Significant effects of dam’s weight at kidding on weights at birth, one month and four months in Malabari ; at birth and a one month in Alpine x Malabari and at birth alone in Saanen x Malabari could be observed. Sire effect was significant on body weights at one month, 4 months and one year in Malabari, at birth and one year in Alpine x Malabari and one year alone in Saanen x Malabari. The growth rate was found to be highest in A x M upto four months of age and afterwards upto one year S X M showed highest rate of gain. The effect of genetic group on growth rate was found to be significant during all the periods of growth. The heritability estimate for weight at birth was near to zero. The h2 estimates were seen getting higher as the age advanced. Genetic correlations between body weights at different ages were found to be fairly high. But the phenotypic correlations between weight at different ages were found to be highly variable. Twins were more than singles in all the genetic groups and the secondary sex ratio was found to be 50:50. The results of the study indicated that crossbreeding of local goats with exotic breeds, Saanen and Alpine, is the desirable breeding plan to accomplish the improvement of body weight in goats, at different ages.
Study of genetic diversity in malabari goats (capra hircus) utilizing biochemical and immunological markers
(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2006) Bindhu, K A; Raghavan, K C
Goat populations of Tanur, Thalassery and Badagara were studied for biochemical polymorphisms, immunological and microsatellite markers to investigate the similarities and differences between these populations. With regard to biochemical markers tested, polymorphism was observed only for haemoglobin, transferrin and glutathione loci. Two variants were observed for haemoglobin, Hb A and Hb B with a frequency of 0.987 and 0.012, respectively, suggestive of three phenotypes, viz. Hb AA, Hb AB and Hb BB, and indicating the predominance of Hb A in the pooled population. Hb B variant was observed only in the Thalassery population (gene frequency 0.038). Two variants for transferrin (TfA and Tf B) were detected with a predominance of TfA in the population. All the goats from Thalassery population belonged to Tf AA type. In the present study only two phenotypes as regards transferrin locus could be observed, (Tf AA and Tf BB) with the notable absence of Tf AB. No polymorphism was observed for albumin, cerruloplasmin, amylase and carbonic anhydrase loci in all the animals tested. The animals were classified as low and high glutathione types based on the values obtained for blood glutathione concentration. In the pooled population, majority of the animals belonged to low GSH type (53.68 per cent). The least square analysis of glutathione concentrations showed significant variation between populations. With regard to potassium loci, all the animals in the present study belonged to low potassium type, with the mean potassium concentration of the pooled population recorded at 4.18 + 0.09 meq/l. The least square analysis of variance of potassium concentrations showed that there existed significant difference between different sub-populations. Genetic distance was calculated as described by Balakrishnan and Sanghvi (1968), using the allelic frequencies of protein polymorphic loci. Genetic distance between Tanur and Badagara was found to be 0.1249 , while that between Tanur and Thalassery was 0.6690 and between Badagara and Thalassery was 0.3351. The only possible conclusion that could be arrived at from the above studies is the existence of a relationship between these populations. Hence an attempt was made to study the different populations at molecular level, using microsatellite markers. Three markers, viz. INRA 063, HUJ 1177and ILSTS 030 were found to be polymorphic. Based on the genetic distances, it was found that Thalssery and Badagara were closely related than Tanur population.. This finding, much in agreement with biometrical traits, reiterates the close relationship between the Thalassry and Badagara populations. On an average, the goats of Thalassery and Badagara were heavier in comparison to Tanur goats, though the prolificacy remained higher in Tanur animals than the other two populations. The different sub-populations under the present study were also screened for the antibody response to SRBC. The highest concentration of antibody was observed on day seventh after primary immunization. The titre gradually reduced by the 15th day, reaching the lowest values on 21st day of post immunization. The effect of antibody response to SRBC on the 7th, 15th and 21st days post immunization was not found to be significant for the occurrence of diseases like diarrhoea and pneumonia. The cutaneous response to intradermal injection to Phytahaemagluttinin – M (PHA-M) was also studied to find out the differences, if any in and between the various sub- populations under study. The values for skin thickness were maximum at 24 hours post-intradermal injection of PHA-M and were recorded as 3.24±0.05, 3.23±0.06 and 3.33±0.06 mm in Tanur, Thalassery and Badagara, respectively. The skin thickness reduced considerably after 48 hours and reached 1.61±0.02, 1.62±0.02 and 1.65±0.02 mm, respectively at 72 hours. The least square analysis of variance revealed that the values for pre and post immunization skin thickness at 0, 24, 48 and 72 hours were non significant between different sub-populations. Total protein, albumin and globulin concentrations also were estimated. The highest mean concentration for globulin was detected in Badagara population (3.28±0.22g/dl) and the lowest in Tanur (2.340 ± 0.31g/dl). The least square analysis of variance of globulin concentration revealed significant difference between populations. Though all populations under study had all predominant physical characteristics of the Malabari breed, the Tanur population stood apart as regards the biometrical characteristics, like litter size and body weight and charecteristics perceivable at the molecular level. It could well be inferred that this population might have evolved through mixing up of the local nondescript Tanur goats with original Malabari goats. The study reiterates the need for more research activities directed at exploring the chances of conserving and developing such unique populations within a breed.