Loading...
Theses
Browse
31 results
Search Results
ThesisItem Open Access Immunodiagnosis of bovine gastrothylacosis using coproantigens(Department of parasitology, College of Veterinary and Animal Sciences, Mannuthy, 2000) Kandasamy, A; KAU; Devada, KA study was conducted on the prevalence of paramphistomatidosis in Thrissur from June 1999 to May 2000, feasibility of coproantigen detection by ELlSA and comparison of sensitivity of ELlSA using coproantigens and ELlSA using serum antibodies in diagnosis of gastrothylacosis, caused by Gastrothy/ax crumenifer, in cattle. It was noted from the registers maintained at the University Veterinary Hospitals at Kokkalai and Mannuthy and that at the Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Mannuthy, that out of a total number of 1534 faecal samples from bovines examined, 253 (16.5 per cent) animals were found to be positive for amphistome eggs with the maximum prevalence (23 per cent) in June and July. Generally the infection was prevalent throughout the year. An indirect ELlSA using rabbit hyperimmune serum against somatic antigens of G. crumenifer was performed to detect coproantigens in faecal samples collected from 100 known G. crumenifer infected cattle. Seventy four samples were found to contain detectable levels of coproantigen indicating a sensitivity of 74 per cent. Serum samples collected from the same infected cattle were tested for antibodies to G. crumenifer by an indirect ELlSA using somatic antigens. Fifty one samples were found positive for antibodies indicating a sensitivity of 51 per cent. It was seen that when 43 cattle were positive for both coproantigens and serum antibodies, 18 cattle were negative for both of them. Although 31 cattle which were negative for serum antibodies were found positive for coproantigens, eight cattle negative for coproantigens were found positive for serum antibodies. The results showed that coproantigen detection, which revealed a higher sensitivity than the detection of serum antibodies by ELlSA, is feasible for the diagnosis of gastrothylacosis in bovines.ThesisItem Open Access Analysis of animal husbandary information in the farm feature pages of leading malayalam dailies(Department of Extension, College of Veterinary and Animal Sciences, Mannuthy, 2000) Sathumadhavan, T P; KAU; Subhadhra, M RStudy was a content analysis of animal husbandry information in farm . feature pages of four Malayalam dailies, namely Malayala Manorama, Mathrubhoorni,. Desabhimani and Deepika, for the period January to December 1999. Variables studied were space provided to different categories of animal husbandry news, modes of presentation, frequency of occurrence of news, seasonality, readability, relevancy and accuracy. Research findings revealed that the studied dailies provided less than one fourth space of farm feature pages for publishing animal husbandry information. Large animal category got more than 50 per cent coverage with three-fourth space occupied by articles on cows. Poultry articles occupied one-fourth space of animal husbandry information of farm feature pages. Where as small animals and pet animals occupied 17 per cent and seven per cent space respectively. News articles occupied maximum column length in all dailies studied. Frequency of occurrence of news articles, illustrations and question answers were found to be more when compared to other modes of presentation. Seasonality studies r.evealed that more than half the number of dairy articles and one eighth of poultry articles were seasonal. Average readability of dairy articles according to Fog index was 5.45 with more reading easiness. More than 50 per cent of dairy articles were found to be relevant. Just above two-third of scientific messages of dairy articles were accurate, whereas accuracy of general articles were found to be nearly 50 per cent.ThesisItem Open Access Nutritive evaluation of squilla (oratosquilla nepa) meal in broiler chicken diets(Department of Animal Nutrition, College of Veterinary and Animal Sciences, Mannuthy, 2000) Kanakasabai, P; KAU; Kunjikutty, NAn experiment was designed and conducted to assess the nutritive value of squilla (Oratosquilla nepa) meal in broiler chicken diet as an animal protein source replacing fish meal protein at three levels viz. zero, 50 and 100 per cent with supplementation of lysine and methionine at 100 per cent level of replacement. One hundred and eighty one – day old straight – run commercial broiler chicks were divided into four groups each with three replicates of fifteen birds and were allotted to four dietary treatments viz. T1 containing 10 per cent unsalted dried fish (control), T2 in which 50 per cent crude protein from dried fish was replaced with squilla meal protein, T3 in which 100 per cent crude protein from dried fish was replaced with squilla meal protein and T4 in which T3 was supplemented with adequate lysine and methionine as per BIS (1992). The rations were made isoproteimic and iso – caloric. The chicks were reared under standard managemental conditions for a period of eight weeks. The birds fed on 100 per cent squilla meal protein dist in replacement of fish meal protein attained significantly lower body weight gain )P < 0.01) compared to those in the control ( T1) and 50 per cent squilla meal protein (T2) group at six and eight weeks. Lysine and methionine supplementation in the 100 per cent squilla meal protein diet improved the weight gain of birds to a level comparable to those on 50 per cent squilla meal protein diet. Feed intake and protein of birds on various dietary treatments at different ages did not differ significantly (P > 0.05). But the feed conversion efficiency of birds maintained on control diet was significantly higher (P < 0.05) at six weeks and eight weeks (P < 0.01) than those on 100 per cent squilla meal protein diet (2.437 vs 2.93). Protein efficiency ratio of birds differed significantly between different treatment groups and the values correlate well with the body weight gain at different ages. Slaughter studies revealed no significant difference (P > 0.05) between the different groups in dressed yield, giblet yield and length of duodenum. However, the abdominal fat was significantly higher (P < 0.01) in control group of birds, while the ready – t0 – cook yield was significantly less (P < 0.05) in 100 per cent squilla meal protein group. The apparent metabolisable energy content of different rations and daily protein retention of birds showed no significant difference between the different dietary treatments. The cost of production per kilogram of live weight gain of birds maintained on the four dietary treatments T1, T2, T3 and T4 were Rs. 26.42, 26.24, 27.25 and 27.79 respectively. Though there was a slight decrease in the cost of production of birds due to incorporation of squilla meal in place of unsalted dried fish at 50 per cent replacement, the difference was insignificant. However, 100 percent replacement of fish meal protein with squilla meal protein and amino acid supplementation to the same increased the cost of production (P < 0.01) with no corresponding increase in performance. From the results obtained in the present study it was inferred that squilla meal can be effectively included in broiler chicken diets to replace 50 per cent of fish meal protein without affecting growth, feed conversion efficiency and the cost of production.ThesisItem Open Access Performance of crosses of indigenous naked neck with white leghorn and new hampshire(Department of Poultry Science, College of Veterinary and Animal Sciences,Mannuthy, 2000) Jomy John, KAU; Leo JosephAn experiment was conducted at Kerala Agricultural University Poultry Farm, Mannuthy, to evaluate and compare the production traits of Naked Neck x White Leghorn (NNWL) and Naked Neck x New Hampshire (NNNH) crosses under deep litter system of rearing from '20 to 40 weeks 'lge. Seventy five pullets of' each cross were housed in identical pens of 15 birds cach and production performance was evaluated for five 28- day periods from February to July 1999. Standard feeding and managemental practices were followed throughout the study . . The NNNH were heavier than NNWL at 20 weeks of age (1855.6 vs l496.lg) and at 40 weeks of age (2436.7 and 2004.1 g). The age at first egg of l46.8±1.48 days in NNNH was significantly earlier than 152±1.3days in NNWL. The age at 50 per cent production was similar in NNWL (162.4 ±1.92 days) and NNNH (164.6 ±1.7 days). The week-wise mean hen housed production in NNWL reached a peak of 80.57 per cent at 26th week of age, while NNNH attained a peak of 81.0 per cent at zs" week of age. The overall mean hen housed number up to 40 weeks of age was 86.39 in NNWL and 83.85 in NNNH. Hen day production remained the same as hen housed production up to 39th week of age and the overall trend was similar. The daily feed consumption from 21 to 40 weeks of age was 124.83g in NNWL and l2S.l4g in NNNH.,The feed conversion ratio per dozen eggs was 2.89 for NNWL and 3.01 for NNNH. Broodiness was shown by nine birds in NNWL for durations ranging from 9 to 63 days while eight birds in NNNH were broody for durations ranging from 22 to 69 days. The mean egg weight from 21 -- 40 weeks was 48.73g in NNWL and 48.44 g in NNNH. The shell thickness was 0.376 mm in NNWL and 0.373 in NNNH. The Haugh unit score was 84.78 in NNWL and 88.00 in NNNH. The plumage Colour in NNWL was off white, but a few birds showed brownish colour on wing feathers. 90 per cent of the NNNH birds had chestnut coloured plumage resembling New Hampshire birds while the rest were multi coloured resembling indigenous Naked Neck birds. Egg shell was tinted in NNWL while NNNH eggs were brown or shades of brown. The livability was 98.7 percent in NNWL, while it was 100 per cent in NNNH. The cost of feed consumed per egg was 202.12 paise for NNWL and 208.94 paise for NNNH [or the entire course of the study. Both NNWL and H cross had statistically comparable hen housed production, egg weight, feed consumption and feed conversion ratio. Both the crosses had excellent livability and good egg quality. However a significantly higher body weight both at 20 and 40 weeks of age, earlier average age at first egg, coloured plumage pattern, and brown shelled eggs in NNNH cross are much preferred by rural farmers, The results of the present study warrants further studies on Naked Neck x New Hampshire cross under field conditions.ThesisItem Open Access Cryosurgical treatment for experimentally induced cataract in dogs 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT)(Department of Surgery, College of Veterinary and Animal Sciences,Mannuthy, 2000) Neelakanta Praveen, Pillai; KAU; Ravindran Nair, SThis study was conducted with the objective of comparing the efficacy of cryo-coagulation and intra-capsular cryo-extraction of experimentally induced cataract in dogs. Twelve nondescript dogs aged approximately one year were used for the study in two groups, A and B, each consisting of six animals. Two clinical cases of cataract were included under the study as Group C. In all the animals of Group A and B, cataract was experimentally induced by injection of 0.5 ml of a 25% solution of calcium borogluconate into the anterior chamber of the eye, in strict aseptic conditionsand under general anaesthesia. In group A. cataract was treated by cryo-coagulation and in Groups Band C intra-capsular cryo-extraction of the cataractous lens was performed after pre-medicating and anaesthetising the animals. Surgery for cryo-coagulation (Group A) or intra-capsular cryo-extraction (Groups B and C) was performed under general anaesthesia with thiopentone sodium after premedication with xylazinc hydrochloride. The anaesthesia was found to be satisfactory at the time of induction and during cataract surgery. Extensive lateral canthotomy was found to be necessary in all the animals at surgery in order to ensure adequate exposure of the globe. Rectal temperature and respiration rate dropped slightly post-operatively, but returned to normal values by the second day after surgery. Pulse rate dropped markedly following surgery, but returned to normal by the sixth day after surgery. Total leukocyte count increased slightly 24 hours after surgery. but then decreased and remained within normal ranges thereafter. There was increase in neutrophil. eosinophil and monocyte count had increased upto 24 hours after surgery. but was normal thereafter. Lymphocyte eount decreased upto 24 hours post-operatively. All the animals .remained in good condition throughout the observation period, except for one animal. Conjunctivitis persisted only in one upto the 11 th day. Corneal oedema persisted throughout the period of observation in four animals. One animal had complete corneal clarity by day seven. In the other animal the cornea cleared on day 23. Uveitis persisted for varymg periods in the animals Photophobia and blepharospasm resolved by day six in all animals. One animal had no posterior or anterior synechiae following surgery and its vitreous body was clear, allowing easy exam ination of the retina. Aqueous flare, indicative of increased protein in the aqueous humour, could not be determined in any animal. Functional vision was not returned in any animal except A4. In Group B, vitreous prolapse occurred during surgical removal of the lens by intra-capsular cryo-extraction. This prolapsed vitreous was excised and did not cause complications. Rectal temperature increased slightly 24 hours after surgery, but had returned to normal values by the 15th post-operative day. Pulse rate decreased slightly 24 hours after surgery, but attained normal values by the second post-operative day and stayed so thereafter. Respiration rate decreased markedly for 24 hours following surgery, but reached normal values two days post-operatively. There was no change in the colour of the mucous membrane of the contralateral eye (used as control) at any time during the period of : observation. The total leukocyte count increased slightly following surgery and continued to be so till 24 hours after surgery and thereafter it decreased and was within normal limits thereafter. The neutrophil count increased till 24 hours post-operatively and returned to normal range thereafter. Lymphocyte count decreased slightly 24 hours after surgery, but returned to normal range by the i s" post-operative day. Eosinophil count increased 24 hours after surgery, but had reached normal values by the i s" post-operative day. Monocyte count became zero after surgery, but then increased slightly and continued so thereafter. All the animals remained in good general condition until the end of the observation period, with no evidence of infection in the operated eye. Intra-ocular pressure decreased slightly following surgery, but had returned to normal ranges by the end of the observation period. Animals B 1, B2 and B4 had persistent conjunctivitis and corneal oedema throughout the period of observation and were unable to negotiate an obstacle course or locate and track mobile or stationary objects even in conditions ofbright ambient light. All other animals in this group were able to perform satisfactorily in the tests of visual function by the end of the observation period. In Group C, treatment of cataract was by intra-capsular cryo- extraction, as in Group B. The results obtained were similar to those for Group B. Animal C2, however. took 52 hours to recover from anaesthesia and died on the sixth day following surgery. The death could not be attributed to complications of cataract surgery. Rectal temperature decreased slightly following surgery, and then increased slightly but returned to normal values at the end of the observation period. Pulse rate decreased immediately after surgery and then returned to normal ranges by the eighth day after surgery. Respiration rate decreased markedly immediately after surgery. but returned to the normal range within 24 hours after surgery. Colour of mucous membrane of the contralateral eye did not show any change at any time during the period of observation. Total leukocytc count increased slightly upto 24 hours after surgery but returned to normal ranges thereafter. The neutrophil and eosinophil and monocyte counts increased after surgery but returned to normal ranges thereafter. The lymphocyte count was markedly decreased at 24 hours after surgery, but then returned to normal ranges thereafter. The surviving animal in Group C showed low grade corneal oedema until day 31 following surgery, but it had blink reflexes and the iris was visible. Conjunctivitis had cleared by day six following surgery. The animals were monitored for visual capability following surgery. The tests were conducted by evaluating the animals' ability to negotiate an obstacle course under photopic and scotopic light conditions, after blind folding the left eye with an eye shield. The animals were also tested for their ability to locate a stationary object and to track a moving object under varying conditions of ambient lighting. Tests of ocular functional integrity were conducted by evaluating menace and photomotor pupillary reflexes. Animal Cl was able to locate or track stationary objects In dim light. It could track moving ohjects in all light conditions. From the results obtained in thc present study. it was found that only one out of the six animals showed restoration of functional vision following treatment of cataract by cryo-coagulation of the lens. In the case of the treatment by intra-capsular cryo-extraction. four out of eight animals showed restoration of functional vision thus showing a success rate of 50% for intra-capsular cryo-extraction of cataract. From the results it can be concluded that: 2. Cataract could be effectively induced using 0.5 ml of calcium borogluconate solution (25%) injected into the anterior chamber of the eye. 3. Pre-medication USing xylazine hydrochloride followed by general anaesthesia USing thiopentone sodium IV was satisfactory for the induction of cataract and the treatment of the cataractous lens. 4. Intra-capsular cryo-extraction IS a better method In treating cataractous lenses in dogs.ThesisItem Open Access Clinico-therapeutic study of ruminal lactic acidosis in goats(Department of Clinical Medicine, College of Veterinary and Animal Sciences,Mannuthy, 2000) Anil Thachil, J; KAU; Baby, P Gwelve goats with history and symptoms suggestive of ruminal acidosis were divided into two groups (I and 11). Six healthy goats were also served as controls. Detailed clinical examination, recording of clinical data, sampling and analysis of rumen liquor and blood were done at zero hour, one hour, 12 h, 24 h, 48 hand 72 h of the study. Therapeutic management of group I was done by giving five per cent sodium bicarbonate solution intravenously at a dose rate of 5 ml / kg ; whereas in group 11 it was replaced with a mixture of sodium carbonate and sodium bicarbonate (carbicarb) intravenously at a dose rate of 4 ml / kg. Animals of group I and 11 were given dexamethasone 20 mg intravenously, evacuated rumen contents and given .. magnesium hydroxide and oxytetracycline orally. Supportive treatments were done with fluids, vitamin B complex inj ection daily and transfer of fresh rumen liquor on second or third day in both groups. The clinical signs noticed were anorexia, dullness, low carriage of head, dry muzzle, sunken eyes, tending of skin, oliguria, distended abdomen, cold extremities and retracted eye balls. There was improvement in the pulse quality and also considerable reduction in respiratory rate noticed in animals of group 11 than in group I at 24 h of .treatment. In both groups, the rumen liquor colour, odour, consistency and protozoal motility became normal, SAT and MBRT showed improvement and elevated rumen liquor lactic acid became normal by 72 h. Elevated haemoglobin, PCV, TEC, TLC and neutrophilia also became normal. Improvement in serum bicarbonate level was marked in group 11 than in group I at 24 hand 48 h of treatment. Serum lactic acid showed significant increase at zero hour in group I and 11, but came to normal in group 11 at 72 h, but not in group I. Elevated serum protein level at zero hour also came to normal. Clinical assessment throughout the study revealed that all animals of group 11 appeared more alert and active and recovered earlier than in group I.ThesisItem Open Access Performance of three introduced breeds of pigs in Kerala(Department of Livestock Production Management, College of Veterinary and Animal Sciences, Mannuthy, 2000) Dinesh, M T; KAU; Thomas, C KA study was conducted to find out the production performance and adaptability of three newly imported breeds of "pigs viz. Duroc, Large White Yorkshire and Landrace and to compare it with that of existing Large White Yorkshire pigs of Kerala. Thirty animals from each group were selected for the study. All the animals were fed with same type of feed through out the experimental period. Body weight and body measurements were recorded at fortnighdy intervals. The quantity of feed consumed by each group was also recorded. Rectal temperature was measured at weekly intervals during the noon hours. Animals were also observed during noon and feeding hours to study the adaptive behavioral manifestations. The results revealed that the body weight of the newly imported pigs were superior to that of Mannuthy Large White Yorkshire pigs. The body weight averaged 64.50+6.63, 62.75±5.16, 82.031±8.50 and 39.89±7.23 between 4.5 to 5 months of age and 171.25+7.69, 173.66+7.38, 169.14±9,98 and 124.66±11.64 between 11 and 11.5 months of age. The newly imported pigs were ready for slaughter at 6.5 to 7.0 months of age while the Mannuthy Large White Yorkshire pigs attained the 100-kg target during 9.5 to 10.months of age. The average daily gain calculated for the Mannuthy Large White Yorkshire pigs was also lower than the three newly imported groups. Average daily gain up to 100 kg body weight averaged 630, 673, 672 and 453 g for Duroc, Large White Yorkshire Landrace and Mannuthy Large White Yorkshire pigs. Feed conversion ratio up to 100 kg body weight averaged 4.03, 3.95, 3.72 and 4.63 for the above four breeds. Results of body measurements show that the Large White Yorkshire pigs maintained at Mannuthy farm was the smallest animal in all weight, groups. Landrace pigs were the longest (120.47 cm) and duroc pigs were the tallest (87.63) at the end of the experimental period. Data regarding the rectal temperature revealed that the temperature recorded for the Mannuthy pigs was slightly higher than the three newly imported groups. Among the four breeds the newly imported Large White Yorkshire pigs were the most aggressive animal at the time of feeding while Duroc pigs were comparatively quiet at the time of feeding. The present study revealed that the overall production performance of Large White Yorkshire pigs, ancestors of which were imported to kerala about 20 years ago, is inferior to that of newly imported Duroc, Large White Yorkshire and Landrace pigs. But the production performance of Mannuthy, Large White Yorkshire pigs was found, to superior to that of many other exotic pigs maintained in other parts of India.ThesisItem Open Access Influence of microbial phytase on nutrient utilization in broilers(Department of Poultry Science, College of Veterinary and Animal Sciences, Mannuthy, 2000) Balasubramanian, D; KAU; Jalaludeen, AAn eight week feeding trial using 180 day-old broiler chicks was conducted to study the influence of phytase supplementation (Natuphos''^-5000) on nutrient utilization and subsequent performance. Treatments involved a standard broiler diet, a low available phosphorus (LAP) diet and the low available phosphorus diet plus graded levels of phytase at the rate of 500, 750 and 1000 units / kg diet. The groups fed standard broiler diet and low available phosphorus diets supplemented with 750 and 1000 units phytase showed significantly (P<0.01) higher body weight and weight gain. The cumulative feed intake was statistically comparable among the experimental diets at sixth week, whereas, at eighth week it was significantly (P<0.05) lower in LAP diet without phytase than that of other diets. The feed conversion ratio was significantly (P<0.01) improved by the addition of phytase at 750 and 1000 units / kg in comparison to low available phosphorus diet. Graded levels of phytase addition linearly improved nitrogen retention while energy retention was significantly (P<0.01) higher in groups fed 750 and 1000 units of phytase / kg. The addition of 750 and 1000 units of phytase / kg diet significantly (P<0.01) increased the availability of calcium while phosphorus availability was improved by all levels of enzyme 500, 750 and 1000 units / kg. The excretion of phosphorus was significantly (P<0.01) reduced in enzyme supplemented groups. The availability of manganese and zinc was significantly more in enzyme supplemented groups. Tibial ash, serum calcium and serum inorganic phosphorus were significantly (P<0.01) increased by the addition of 750 and 1000 units of dietary phytase / kg both at sixth and eighth week of age. The serum alkaline phosphatase level was significantly (PO.Ol) decreased in the diets supplemented with phytase. Supplementation of phytase had no effect on per cent dressed yield and giblet yield. The per cent R-to-C yield was significantly (P<0.05) higher in groups fed standard diet, LAP diet and 500 units phytase supplemented diet at sixth week. Whereas at eighth week it was significantly (P<0.05) higher in groups fed standard diet and 1000 units phytase added diet. The livability was not influenced by dietary phytase and available phosphorus levels. The net profit per kg live weight at eighth week was 29, 94 and 85 paise higher in groups fed 500, 750 and 1000 units of phytase, respectively in comparison to LAP diet. The results suggested that supplementation of 750 units of phytase per kg in low available phosphorus diets is advantageous for commercial broiler chicken production.ThesisItem Open Access Body weight and its association with age at first calving and milk production in crossbred cattle of Kerala(Department of Animal Breeding and Genetics, College of Veterinary and Animal Sciences, Mannuthy, 2000) Siddalingswamy Hiremath; KAU; Stephen MathewThe present study was undertaken with a VIew of estimating body weights of crossbred calves in the field conditions of Kerala at birth, three, six and twelve months of age and to find association of these body weights with age at first calving and first lactation milk yield. The data for the present study were taken from the records of ICAR Field Progeny Testing Scheme of Centre for Advanced Studies in Animal Genetics and Breeding, Kerala Agricultural University. The data were of the 1993-2000 period. Body weights at birth, 3, 6, 12 months and at calving were predicted from body measurements using Minnesota formula given by J ohnson,( 1940). The data were analyzed using least squares analysis of variance to study the effects of non-genetic factors on different traits under study. The data adjusted for significant non-genetic factors .. were used to study the effect of sire and for estimating heritability and correlation among body weights and between body weights and age at first calving and between body weights and first lactation milk yield. The overall average body weights of crossbred calves at birth, 3,6 and 12 months of age were 26.0 ± 0.38 kg, 48.7 ± 1.26 kg, 74.1 ± 2.81 kg and 151.0 ± 7.74 kg, respectively. Least squares analysis of variance has shown that the effect of season of birth was significant (P~0.05) only on body weight at six months of age. The influence of period of birth was significant for all body weights upto one year age except for body weight at six months of age. Centre was a significant source of variation for all body weights upto one year age, The mean Age at First Insemination, Age at first calving and Weight at first calving of crossbred cattle were 689.3 ± 22.9 days, 1013.6 ± 21.74 days and 284.9 ± 7.71 kg respectively. The season of birth did not affect age at first insemination, age at first calving and weight at first calving. The significant (P~0.05) influence of period of birth and centre were 11 observed on age at first insemination and age at first calving only but not on weight at first calving. The effect of period of calving and centre on first lactation milk yield was significant whereas the effect of season of calving and age at first calving did not affect first lactation milk yield. The average first lactation milk yield of crossbred cows was 1958.5 ± 30.74 litres. The sire wise means of body weight at six months of age, weight at first calving and first lactation milk yield did not differ significantly but sire effect was significant (P~0.05) in all the other traits. Heritability estimates were calculated by paternal half sib method for different traits under study. The low heritability estimate was obtained for birth weight, body weight at six months of age, age at first calving and weight at first calving. But the heritability estimates of body weight at three months of age and body weight at twelve months of age were high. Age at first insemination was moderately heritable. The heritability estimate of first lactation milk yield was -0.069 ± 0.05. iii Association among body weights and that between body weights and age at first calving followed no definite trend. However, the genetic correlation (0.46) between body weight at six months and first lactation milk yield and high, positive (> 1) genetic correlation between body weight at twelve months and first lactation milk yield indicates strong genetic association of body weight at six months and body weight at twelve months with first lactation milk yield and their relationship can be used advantageously for selection of heifers for milk production under field conditions
