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ThesisItem Open Access Marker assisted selection for milk production traits in vechur cattle(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences Mannuthy, 2005) Shymaja, Uthaman; Raghunandanan, K VThesisItem Open Access Milk protein polymorphism and milk composition in Vechur cattle(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1996) Thirupathy Venkatachalapathy; KAU; Sosama, IypeThe native cattle of Kerala have been evolved through several generations of natural selection against high humidity, heavy rainfall and hot climate. They have been considered as non – descript animals, but there has been variety with characters distinguishing from others and known as Vechur Cattle of Kerala. The Vechur cattle had their origin in Vechur near Vaikom of Kottayam district of Kerala. They were very popular four decades back for their relatively higher milk production compared to other local cows. The extremely small size of the cow, good adaptation and high disease resistance are the traits very much favoured by the farmers. Farmers preferred Vechur cattle for ploughing in marshy lands because of the small size and light weight. The emergence of crossbreeding led to the gradual reduction in traditionally reared Vechur cattle. Under this circumstances, the present work was undertaken to characterise the Vechur cattle of Kerala by studying (a) certain genetic markers in milk (b) milk components like fat, total solids and solids not fat percentage (c) fat globule size and distribution and (d) iodine value. The Vechur cows maintained under the scheme on “Conservation of germplasm of Vechur cattle” formed the material for the study. Milk proteins such as casein and whey proteins were studied by polyacrylamide gel electrophoresis in horizontal dimension (Thompson and kiddy, 1963). The fat, total solids, solids not fat percentage of milk and iodine value of milk fat were estimated as prescribed by Indian Institution Standards. The fat globule size was measured under microscope by fitting an eye piece micrometer to the eye piece of the microscope. The statistical analysis were done as suggested by Snedecor and Cochran (1967). The influence of stage and time of milking were worked out using least squares analysis of variance as described by Harvey (1986). Three proteins α, β and k – casein were identified in casein system. At αsl – casein locus three phenotypes viz. BB, and CC determined by two allele B and C were observed. Frequency of CC phenotype (0.64) was highest a followed by BC (0.22) and BB (0.14). Frequency of B and C allele were 0.25 and 0.75. The β – casein locus consisted three phenotypes viz. AA, AB and BB with A and B allele. The frequency of AB phenotype was highest (0.57) followed by AA (0.29) and BB (0.14). Frequency of A allele was 0.57. At k – casein locus two phenotypes AA and AB with A and B allele were identified. The frequency of AB was (0.83) and frequency of A allele was 0.59. Two whey proteins α – lactalbumin and β – lactoglobulin were identified. At α – lactalbumin locus two phenotypes AA and AB with two allele A and B were observed. The frequency of AA and AB phenotypes were 0.57 and 0.43. The frequency of A and B allele were 0.78 and 0.22 respectively. The β – lactoglobulin locus consisted of three phenotypes viz. AA, AB and BB with A and B allele with frequency of 0.57, 0.29 and 0.14 respectively were identified. The frequency of A allele was 0.71. The frequency of C allele at αsl – casein locus was lower than the other Indian breeds like Sahiwal, Tharparkar, Red Sindhi and Rathi, but higher than exotic breeds like Jersey and Holstein and crossbred cattle of Kerala. The A variant at β and k – casein locus had frequency lower to other Indian breeds, exotic breeds of cattle and crossbred cattle of Kerala. The A variant at α – lactalbumin and β – lactoglobulin locus had much higher frequency than other Indian, exotic breeds of cattle of cattle and crossbred cattle of Kerala. B variant in vechur cattle was lower in frequency compared to other Indian breeds. The average milk fat percentage for 1 – 44 weeks of lactation was 5.95 + 0.12, 6.62 + 0.13 in the morning and evening respectively and the mean milk fat percentage for morning and evening milk was 6.23 + 0.19. The mean milk fat percentage at first week was 4.05 + 0.19, 4.65 + 0.17 and by 20th week of lactation was 5.92 + 0.08, 6.55 + 0.07 in the morning and evening milk respectively. The evening milk had uniformly higher fat percentage than morning milk. The fat percentage showed an increasing trend with advancing stage of lactation. The least squares means for morning and evening milk were 5.99 + 0.03 and 6.62 + 0.03 respectively and overall mean was 6.13 + 0.04. The mean total solids percentage of milk at first week was 12.64 + 0.17 and 13.57 + 0.19 in the morning and evening milk and it steadily increased to 14.75 + 0.13 and 15.31 + 0.18 in the morning and evening milk by 20th week of lactation. The average total solids percentage in milk from 1 – 44 weeks of lactation was 14.79 + 0.13 and 15.53 + 0.13 in the morning and evening respectively and the average for morning and evening together was 15.16 + 0.11 per cent. An increasing trend was noticed in total solids percentage as the lactation advanced. The evening milk showed uniformly higher total solids percentage compared to morning. The least squares mean was 15.02 and the adjusted mean for morning and evening was 14.85 + 0.05 and 15.55 + 0.05 percent. Least squares analysis of variance showed a significant effect of time of milking and stage of lactation on milk fat and total solids percentage of milk. The average solids not fat percentage from 1 – 44 weeks of lactation was 8.84 + 0.12 and 8.92 + 0.14 in the morning and evening milk respectively. The average for morning and evening milk was 8.88 + 0.13 and least squares mean was 8.90. The mean solids not fat percentage of milk at first week was 8.60 + 0.24 and 8.93 + 0.22. It was 8.83 + 0.11 and 8.76 + 0.15 percent at 20th week of lactation in the morning and evening milk respectively. No trend of increase was noticed in the solids not fat percentage in relation to the stage of lactation. The least squares analysis of variance showed no significant effect of time of miling and stage of lactation on solids not fat percentage. Total solids and solids not fat did not have strong association in general. The positive correlation between total solids and fat percentage were not significant. The negative correlation between fat and solids not fat percentage were also not significant. The milk fat and total solids percentage were higher than other Indian breeds of cattle, but lower to buffalo. The solids not fat percentage of milk was similar to other Indian breeds of cattle. The mean size of fat globule was 3.21 µ and the range was 2.54 to 4.07 µ. The mean diameter of fat globules was found to be 3.02 + 0.05 µ in the morning and 3.40 + 0.05 µ in the evening milk. The mean size of fat globules estimated in goat (Malabari and their crosses), crossbred cattle and Murrah buffalo were 2.60 µ, 4.87 µ and 5.81 µ respectively. The average fat globule size was found to be decreasing as the lactation advanced. The proportion of small size fat globules were found to be increased and the larger size of fat globules decreased towards the end of lactation. No correlation was noticed between fat globules size and fat percentage. The iodine value ranged from 28.61 to 30.29 and the average iodine value was 29.60 + 2.20. Based on available reports this appeared to be similar to buffalo, higher than goat and lower than cows. The size of fat globule (3.21 µ) was higher than the goat and lower to the other breeds of cattle and buffalo. Since the milk fat has higher production of smaller size fat globules and saturated fatty acids, it would be therapeutically useful in malabsorption syndromes due to its easy digestability. The larger proportion of small size fat globule is associated with high phospholipid content because of greater surface area. Phospholipids are important in the development of nervous system in babies. Thus Vechur cow milk appear to be suitable for infants and even sick. Studies on more number of cows are required for confirmation of results. It can be concluded that Vechur cattle of Kerala has unique characteristics of its own and have separate identity from other breeds of cattle not only by its small size but also due to its milk protein variants, composition of milk, size of fat globules and level of saturated fatty acids.ThesisItem Open Access Evaluation of boer halfbreds for development of meat goat strains suited for Kerala(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2004) Jeeva, L; KAU; Nandakumar, PThe tremendous potential of goat production in Kerala State is constrained due to the non-availability of meat type of goats suited to our climatic conditions. Malabari goats native to Kerala and improved Alpine Malabari (AM) grows to around only 8.5 and 11 kg respectively, imposing severe restrictions on commercial exploitation of these breeds. Introgression of Boer inheritance into Australian feral goats has led to the development of Australian goat meat industry and utilization of Boer goats to improve local goats in Maharashtra has paid rich dividend. With this background, the present investigation undertaken in Alpine Malabari crosses (AM) by infusing Boer inheritance was undertaken at University Goat and Sheep Farm was to evaluate the suitability of Alpine Malabari x Boer (AMB) crosses as a meat strain suited to Kerala State. Data on one hundred goat kids, 50 each belonging to 2 genetic groups, AM and AMB were subjected to least squares analysis to resolve the effect of genetic group, sire, month of birth and sex on type of birth, litter weight at birth, birth weight, body weight at first, second, third, fourth, fifth and sixth month, pre- weaning mortality, incidence of neonatal diseases, litter size at weaning, average daily gain in body weight, phenotypic correlation, viability and adaptability. Average litter size at birth (LSB) among Alpine Malabari (AM) and , Alpine Malabari x Boer (AMB) kids was 1.79±0.48. Alpine Malabari kid had a significantly (P:S0.05) higher litter size ~t birth of 2. I 2±0. I 6. Month of birth had a highly significant (P~O.OI) effect on litter size at birth with highest litter in July (2.2±0.17). Sire influences were highly significant on litter size at birth while sex had no significant influence on litter size at birth. Mean litter weight at birth was 3.77 kg and it was not found to be significantly affected by genetic group and sex. Month of birth and sire had highly significant associations with litter weight at birth. Alpine Malabari x Boer kids had a highly significant (P::::O.Ol) and higher body weight from birth to sixth month of age. Body weight in AMB kids was 2.38,6.01, 8.92 and 11.65 kg while AM kids had only 1.8,2.87,3.05 and 4.30 kg respectively at birth, one, two and three months respectively. Buck had a highly significant influence on birth weight of kid and body weight at first, second and third month. Month of birth had a significant influence on birth weight and body weights at first, second and third month. Incidence of enteritis was 0.31, respiratory infection 0.08 and pre- weaning mortality was 0.07. Effects of genetic group and sire were significant on respiratory infections and not on incidence of enteritis and pre-weaning mortality. Month of birth did not exert significant influence on respiratory infections, enteritis or pre-weaning mortality. The mean body weights at fourth, fifth and sixth month in AM and AMB crosses were 10.34 kg, 11.96 kg and 13.68 kg respectively. The effect of genetic group on body weights at fourth, fifth and sixth month was highly significant and superior in AMB crosses with 13.62 kg, 15.73 kg and 17.79 kg respectively while it was only 5.76 kg, 5.84 kg and 6.81 kg respectively in AM crosses. Sire effects were highly significant on the body weights at fourth, fifth and sixth month. Month of birth contribute to the body weights to a highly significant level and kids born in April and December were found to have higher body weights from fourth to fifth month. Sex of the kids was not found to influence the body weights from fourth to sixth month. The mean average daily gain in body weight (ADG) from birth to third month was 7r.36 g, from third to sixth month was 65.7 g and birth to sixth month was 66.7 g. AMB crosses had a highly significant ADG of 104.89 and 86.58 compared to 35.19 and 39.1 g during 0-3 and 0-6 month respectively. Sire influences were highly significant on ADG from 0-3 and 0-6 month. Month of birth had a highly significant effect on ADG and highest ADG was for kids born during April. Birth weight had a highly significant positive correlation with average daily gain in body weight from birth to third month and average daily gain in body weight from birth to sixth month and body weights from first to sixth month. Correlation between respiratory infections and pre-weaning mortality were highly significant. Average daily gain in body weight from birth to third month had a highly significant negative correlation with respiratory infection and pre-weaning mortality. Significantly higher litter size at birth in AM crosses over AMB crosses direct to the feasibility of AM genotype of enhancing litter size at birth which might partially be also contributed by use of oestrus synchronization on frozen semen technology in production of AMB crosses. Modulation of litter size at birth by month of birth reflect on the environmental factors influencing the ovulation rate, conception rate and embryonic survival. Monthly body weights from birth to six months was found to be highly superior in AMB crosses indicating the Boer superiority in enhancing body weights of AMB crosses. Significant effect of sire on these trait suggest of the additive genetic effect which might improve body weight in Boer crossbred goats. Contribution of month of birth on bodyweight probably influenced by ambient temperature, availability of biomass, offers potential for improvement of these traits by appropriate managemental strategies. Increased incidence of diseases in AM genetic group with higher pre-weaning mortality is worth for further investigation. ADG 0-3, ADG 0-6 were significantly higher in AMB crosses highlighting the importance of Boer development in improvement of growth rate of goats. The role of month of birth in variations in ADG partially reflect on the environmental conditions can adversely affect the growth rate. Phenotypic correlations, which were positive and highly significant between birth weight, ADG and body weight are suggestive benefits of early selection on birth weights for enhanced, slaughter weights. The negative correlation of ADG and incidence of pneumonia, pre- weaning mortality and enteritis could be used for the development of goats adapted to local climatic conditions.ThesisItem Open Access Evaluation of Lactation Performance of Zebu x Taurus Cattle in Kerala(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences,Mannuthy, 1983) Stephan, Mathew; KAU; Mukundhan, GAn investigation was undertaken to evaluate the lactation performance of the crossbred cattle (Zebu x Taurus) and to compare the performance of Brown Swiss and Jersey crosses under field conditions so that a breeding policy could be recommended. First lactation milk yield in 305 days, age at first calving and first lactation length were the characters studied. For this, data on the Brown Swiss crossbred maintained by the farmers at Mavelikkara and Kattappana and on Jersey crossbreds at Kanjirappally and Chalakudy under the milk recording – cum – progeny testing scheme of the Kerala Livestock Development and Milk Marketing Board were utilized. The observations spread over a period of four years from 1978 to 1981. The uncorrected average first lactation yields were 1508.8 + 14.3 kg in Brown Swiss half – breds, 1562.6 + 28.7 kg in unclassified Brown Swiss crosses, 1380.3 + 47.0 kg in Jersey half – breds and 1558.0 + 31.5 kg in unclassified Jersey crosses. The least squares means of first lactation yields in Brown Swiss half – breds, unclassified Brown Swiss crosses, Jersey half – breds and unclassified Jersey crosses were 1482.0 + 19.7 kg, 1544.7 + 32.4 kg, 1359.2 + 57.4 kg and 1559.8 + 37.3 kg respectively. The Duncan’s multiple range test showed that the Jersey half – breds had significantly lower production compared to all other genetic groups. The production of unclassified Jersey crosses had been significantly higher than the Brown Swiss half – breds as well as Jersey half – breds. Least squares analysis on pooled data and Brown Swiss half – breds showed the significant influence of age at first calving, year of calving and sex of the calf on first lactation milk yield. But, season of calving did not significantly influence the milk yield. The uncorrected average age at first calving in Brown Swiss half – breds, unclassified Brown Swiss crosses, Jersey half _ breds and unclassified Jersey crosses were 46.0 + 0.4 months, 38.4 + 0.6 months, 41.7 + 1.4 months and 39.5 + 1.2 months respectively. The least squares means of age at first calving in Brown Swiss half – breds, unclassified Brown Swiss crosses, Jersey half – breds and unclassified Jersey crosses were 46.0 + 0.5, 38.0 + 0.8, 41.1 + 2.1 and 38.9 + 1.5 months respectively. Brown Swiss half – breds had significantly higher age at first calving compared to the other three groups which were homogenous. The effect of year on age at first calving was not significant in Brown Swiss half – breds while pooled data analysis showed a significant effect of year on age at first calving. The uncorrected average lactation lengths in Brown Swiss half – breds, unclassified Brown Swiss crosses, Jersey half – breds and unclassified Jersey crosses were 300.5 + 0.5 days, 299.6 + 1.0 days, 295.6 + 2.4 days and 295.3 + 1.7 days, respectively. This shows that all the crossbreds had fairly good lactation length. Lactation milk yield and age at first calving are economically important to the farmer and in this context these two characters are to be considered together. The results obtained do not indicate the superiority of either Brown Swiss or Jersey crossbreds, over the other. The introduction of both Brown Swiss and Jersey improved the milk production of the cattle of Kerala. While aiming at a further improvement, emphasis should be given to the merit of the sires rather than the specificity of the exotic breed or the percentage of exotic inheritance.ThesisItem Open Access Chromosome profile of Indian elephants ( Elephas maximus indicus)(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1988) Sakthi Kumar, A; KAU; Mukundan, GA karyological study in Indian elephants using peripheral venous blood collected from 7 tuskers, 7 cow elephants and one makhna belonging to some temples and private owners of Trichur District was undertaken with objectives of a) to evolve a technique for chromosome studies of elephants. b) to find out the chromosome number in Indian elephants, and c) to suggest sex chromosome mechanism in sex determination. Standardization of technique Comparison of efficacy of phytohaemagglutinin – M (Difco) and Poke – weed mitogen (GIBCO), in two different culture media namely TC 199 and RPMI – 1640, as mitogens showed that phyto – haemagglutinin – M yielded a mitotic index of 0.33 and 0.66 per cent in medium TC 199 and RPMI – 1640 respectively; poke – weed mitogen yielded a mitotic index of 5.33 and 5.66 per cent respectively in TC 199 and RPMI – 1640. Statistical analysis revealed that the efficacy of the two different media used was not significantly different, whereas the efficacy of two mitogens differed significantly at five per cent level. Poke – weed mitogen was found to be better than phytohaemagglutinin – M as far as indusing mitoses in elephant lymphocyte cultures over a 72 hour culture period was concerned. Colchicine treatment using 0.1 ml colchicine solution (0.0001%) for a period of one hour yielded satisfactory chromosome preparations. Karyotype The karyotype of the tusker, cow elephant and makhna revealed a diploid chromosome number of 2n = 56, comprising of 54 autosomes and 2 sex chromosomes. The autosomes were classified into 6 submetacentric and 21 acrocentric chromosomes. The X – chromosome was a submetacentric in all the three groups of elephants whereas the Y – chromosome was a small acrocentric in the tusker as well as the makhna. Analysis of relative length of chromosomes showed that the largest chromosome pair measured a relative length of 6.973 per cent and the smallest chromosome was the Y – chromosome measuring a relative length of 1.710 per cent. Position of centromere on the basis of centromeric index suggested that the centromere was farthest from the centre of the chromosome in the second autosome pair and nearest to the centre in the X – chromosome among the submetacentric chromosomes. Neither autosomes nor sex chromosomes possessed satellites on karyological examination. The elephants studied exhibited XX/XY sex chromosome mechanism. The cow elephant possessed XX sex chromosome complement while both tusker and makhna possessed XY sex chromosome complement. A comparison between the karyotypes of tusker and makhna did not show any variation in (a) basic number, (b) relative length (C) position of centromere, (d) absence of satellites on the chromosomes and (e) the sex chromosome complement. It may be concluded that tusklessness in makhna is not associated with either euploidy or aneuploidy.ThesisItem Open Access Prevalence of yeast and yeast like fungi in bovine mastitis and their in vitro drug sensitivity(Department of Microbiology, College of Veterinary and Animal Sciences, Mannuthy, 1995) Sukumar, K; KAU; James, P CThe present investigation was undertaken to identify the the biochemical polymorphism at serum alkaline phospha tase (SAP) loci and to study the heterogenity of SAP variation in crossbred cattle It was also envisaged to analyse the association of SAP variation and traits of economic importance such as milk production and composition of milk One hundred and ten animals belonging to two different crosses of local nondescript cattle viz Crossbred Holstein Friesian (57) and Crossbred Brown Swiss (53) were typed for SAP variance by standardising Horizontal Polyacrylamide Gel Electrophoresis (PAGE) Two genotypes FS and SS were determined The highest frequency of FS genotype was in Holstein Friesian crossbred than in Brown Swiss crossbred The genotype FF was absent in both the crossbreds The highest frequency of SS genotype was in Brown Swiss crossbred than in Holstein Friesian crossbreds Two alleles namely pF and P$ with two phenotypes FS and SS were identified as SAP locus pT allele had the frequency of 0 20 and pS allele had the frequency of 0 80 in the pooled crossbreds Both the Holstein Friesian crossbreds and Brown Swiss crossbred are in genetic equilibrium at the SAP loci No association could be established between milk yield (305 days) and serum alkaline phosphatase level A non significant negative correlation existed between milk fat percentage and SAP level whereas a significant positive correlation existed between milk SNF percentage and SAP level The correlation between SAP level and milk total solids were found to be negative and non significant in Brown Swiss crossbreds whereas a non significant positive correlation existed between the SAP level and milk total solids in Holstein Friesian crossbreds Animals belonging to the FS genotype are better milk producers compared to the SS genotype For higher fat percentages the performance of SS genotype was compara tively better The performance of SS genotype is better for producing milk with more than 8 5 percentage of SNF FS genotype performed better for producing milk having higher percentage of total solidsThesisItem Open Access Parentage control in cattle using blood types(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1992) Mary John, V; KAU; Nandakumaran, BImmunogenetic studies were carried out in four hundred and eleven cross-bred cattle maintained at the University Livestock Farm, Mannuthy and Cattle Breeding Farm , Thumburmuzhi The animals belonged to three genetic groups, viz Jersey cross breds, Brown-Swiss cross breds and Holstein Friesian cross breds The animals were typed for blood group factors and haemoglobin Blood group reagents were produced from iso immune sera, hetero immune rabbit sera and colostrum of an immunised cow Eleven reagents were produced by the above cited methods and seven of them were comparable to international reagents Serum from two animals (Animal Nos 248 and 743) were used as sources of anti J whose titres were being assessed periodically by haemolytic technique The titre varied from 0 to 1 32, but no association with seasons of the year, could be noticed Typing of cross bred animals was done with 28 blood group reagents (14 internationally comparable and 14 new reagents) The internationally comparable reagents were B, Y25 E 3 , C23 R, , F, V, J, L, S, H and Z Anti J from two different sources (Animal Nos 248 and 743) were used and one (Animal No 743) seemed to be the sub type of other (Animal No 248) Standard haemolytic test was carried out for typing animals for their blood group factors The factors occurred in the three genetic groups with varying gene frequencies A good agreement was observed between the observed and expected numbers in each genotypes with respect to FV locus in all the population except in Holstein Friesian cross breds (P < 0 05 ) The mode inheritance of blood group factors showed that the cattle red blood cell antigenic factors were inherited as dominant over their absence The cross-bred population was also typed for haemoglobin Electrophoresis was carried out in poly acrylamide gel Only two haemoglobin variants viz HbA and HbB and three phenotypes viz Hb AA, Hb AB and Hb BB were A observed The gene frequencies of Hb allele was 0 67, 0 6 6 and 0 83 m Jersey cross breds, Brown Swiss cross breds and Holstein Friesian cross-breds, respectively The genotype frequencies at haemoglobin locus for the pooled cross breds were 0 5036 (Hb AA), 0 4307 (Hb AB) and 0 0657 (Hb BB), respectively Genetic variability of breeds was studied m terms of heterozygosity at Hb locus and Friesian cross breds were found to have least heterozygosity, ie 0 282ThesisItem Open Access Biochemical polymorphism in broiler rabbits(Department of Animal Breeding, Genetics and Biostatistics, College of Veterinary and Animal Sciences, Mannuthy, 1990) Usha, A P; KAU; Mukundan, GBlood samples collected from rabbits maintained in the rabbit breeding farm of Kerala Agricultural University formed the materials for this study These blood samples were typed employing horizontal polyacrylamide gel electrophoresis to study the polymorphism of transferrin post transferrin and haemoglobin A total of 152 rabbits comprising of 50 Soviet Chinchilla 52 Newzealand White and 50 local rabbits were involved m the study Genetic inter relationship among growth traits and survivability were studied In all the genetic groups two transferrin variants the faster Tf and slower Tf with two phenotypes TfAA and TfAC were observed The gene frequency of Tf and Tf were 0 7500 and 0 2500 in Soviet Chinchilla 0 8300 and 0 1700 m Newzealand White and 0 8100 and 0 1900 m local rabbits The frequency of TfA allele was higher in all the populations The phenotype TfCC was not observed in any of the genetic groups Three post transferrin phenotypes Ptf FF Ptf FS and Ptf SS were detected and found to be controlled by two F S co dominant alleles Ptf and Ptf The fast moving F variant was designated as Ptf and the slow moving migrant S F was designated as Ptf The gene frequency of Ptf was 0 7400 0 8500 and 0 7600 m the three genetic groups and e that of Ptf was 0 2600 0 1500 and 0 2400 in Soviet Chinchilla Newzealand White and local rabbits respectively Haemoglobin was found to be monomorphic in all the three genetic groups studied The allelic frequencies of transferrin and post transferrin were suggestive of Hardy Weinberg equilibrium in the populations of three breeds No significant diversity was found to exist between genetic groups analysis of segretation pattern observed in pedigrees revealed the autosomal codominant mode of inheritance for transferrin and post transferrin alleles The absence of TfCC phenotype in the whole population of rabbits may be due to its unfavourable influence on the viabilityThesisItem Open Access Studies on the peak yield and persistency of lactation in crossbred dairy cows(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 1980) Girija, C R; KAU; Krishnan, Nair B RWith the objective of studying the peak yield, persistency, their relation with other production traits and the shape of the lactation curves, the data on the production and reproduction records of 298 Jersey x Zebu and 69 Brown Swiss x Zebu crossbred cows maintained at Livestock farms of Kerala Agricultural University were utilized. Persistency was calculated as a ratio of the yield from the attainment of peak yield to the 305 days yield and the yield upto the peak yield.
