Tharparkar Cows Research Articles

Genome-wide selection signatures address trait specific candidate genes in cattle indigenous to arid regions of India

The peculiarity of Indian cattle lies in milk quality, resistance to diseases and stressors as well as adaptability. The investigation addressed selection signatures in Gir and Tharparkar cattle, belonging to arid ecotypes of India. Double digest restriction-site associated DNA sequencing (ddRAD-seq) yielded nearly 26 million high-quality reads from unrelated seven Gir and seven Tharparkar cows. In all, 19,127 high-quality SNPs were processed for selection signature analysis. An approach involving within-population composite likelihood ratio (CLR) statistics and between-population F ST statistics was used to capture selection signatures within and between the breeds, respectively. A total of 191 selection signatures were addressed using CLR and F ST approaches. Selection signatures overlapping 86 and 73 genes were detected as Gir- and Tharparkar-specific, respectively. Notably, genes related to production (CACNA1D, GHRHR), reproduction (ESR1, RBMS3), immunity (NOSTRIN, IL12B) and adaptation (ADAM22, ASL) were annotated to selection signatures. Gene pathway analysis revealed genes in insulin/IGF pathway for milk production, gonadotropin releasing hormone pathway for reproduction, Wnt signalling pathway and chemokine and cytokine signalling pathway for adaptation. This is the first study where selection signatures are identified using ddRAD-seq in indicine cattle breeds. The study shall help in conservation and leveraging genetic improvements in Gir and Tharparkar cattle.

Comparative assessment of the effective population size and linkage disequilibrium of Karan Fries cattle revealed viable population dynamics.

Karan Fries (KF), a high-producing composite cattle was developed through crossing indicine Tharparkar cows with taurine bulls (Holstein Friesian, Brown Swiss, and Jersey), to increase the milk yield across India. This composite cattle population must maintain sufficient genetic diversity for long-term development and breed improvement in the coming years. The level of linkage disequilibrium (LD) measures the influence of population genetic forces on the genomic structure and provides insights into the evolutionary history of populations, while the decay of LD is important in understanding the limits of genome-wide association studies for a population. Effective population size (Ne) which is genomically based on LD accumulated over the course of previous generations, is a valuable tool for e valuation of the genetic diversity and level of inbreeding. The present study was undertaken to understand KF population dynamics through the estimation of Ne and LD for the longterm sustainability of these breeds. The present study included 96 KF samples genotyped using Illumina HDBovine array to estimate the effective population and examine the LD pattern. The genotype data were also obtained for other crossbreds (Santa Gertrudis, Brangus, and Beefmaster) and Holstein Friesian cattle for comparison purposes. The average LD between single nucleotide polymorphisms (SNPs) was r2 = 0.13 in the present study. LD decay (r2 = 0.2) was observed at 40 kb inter-marker distance, indicating a panel with 62,765 SNPs was sufficient for genomic breeding value estimation in KF cattle. The pedigree-based Ne of KF was determined to be 78, while the Ne estimates obtained using LD-based methods were 52 (SNeP) and 219 (genetic optimization for Ne estimation), respectively. KF cattle have an Ne exceeding the FAO's minimum recommended level of 50, which was desirable. The study also revealed significant population dynamics of KF cattle and increased our understanding of devising suitable breeding strategies for longterm sustainable development.

Evaluation of sexed semen-based artificial insemination in Tharparkar cattle under organized farm condition.

Sexed semen facilitates additional female calf production for the expansion of a herd at a faster rate and also curtails the surplus production of unwanted male calves. A study was conducted to evaluate the performance of sexed semen in indigenous Tharparkar cows based on 114 artificial inseminations (AI) performed at natural oestrus using two protocols i.e., single AI (n = 48) and double AI (n = 66). Overall, the first service conception rate (CR) was significantly higher in double (53.0%) than single (33.3%) AI protocol. The odds ratio of conception rate in double AI was 2.26 (χ2 = 4.4, df = 1, p = .04) with respect to single AI. The time that elapsed since the detection of oestrus to insemination was also analysed. In a single AI protocol, the CR was higher (p < .05) at 16 h (54.6%) than insemination at 8 h (27.0%) following the onset of oestrus. Yet, the CR using double AI protocol did not differ (p = .73) significantly when AIs were performed either at 8 h and 24 h (51.9%) or 16 h and 24 h (57.1%) post onset of oestrus. Besides, like the single AI protocol, the parity of the animals also influenced the CR, being higher in heifers (n = 22) than those of parous (n = 92) cows (72.73 vs. 40.43%, χ2 = 7.48, df = 1, p = .006) in the present study. The odds ratio of conception in heifers was 3.93 with respect to parous cows. Overall, the birth of female calf was 91.7%. In conclusion, the present study indicates a future promise of the sexed semen for the production of more female offspring from Tharparkar cattle.

Comparative study of multiple linear regression and artificial neural network forprediction of first lactation 305-days milk yield in Tharparkar cattle

The present investigation was undertaken on 3266weekly test day milk yield records of first lactation Tharparkar cows spread over a period of 8 years (2012-2020) maintained at Livestock Research Station, Beechwal, Bikaner. The weekly test day milk yields (WTD) were used to develop best multiple linear regressions (MLR) and artificial neural network (ANN) model for prediction of first lactation 305-days milk yield (FL305DMY).Further, the comparison was made between MLR and ANN model based on coefficient of determination (R2) and root mean square error (RMSE). Artificial Neural Network was trained using backpropagation algorithms viz. Scaled conjugate gradient (SCG). It has been observed that the coefficient of determination of the models was increased with the addition of test day milk yields as input variables. It was inferred from the study that artificial neural network was better than the multiple linear regression to predictFL305DMY with more than 70% accuracy by almost all the input sets at early as 117th day of the lactation with lesser value of RMSE in comparison to MLR. Therefore, it is concluded that ANN is a potential tool for the prediction of the first lactation305-days milk yield in Tharparkar cattle than multiple linear regression.

Effect of Floor Enrichment with Rubber Mattress of Calving Pen on Prepartum Behaviour of Tharparkar Cow during Winter Season

Background: The study was conducted to evaluate the effect of floor enrichment with rubber mattress of calving pen on prepartum calving behaviour of Tharparkar cow during the winter season. Methods: A total 28 Tharparkar cows were taken in study during winter season (November to March) and divided into two groups each contain 14 animals. One group placed in floor enriched with rubber mattress and other group kept on bare concrete floor calving pen. Preparturient behaviours like lying time, standing time, lying bout duration, number of lying bouts, rumination time ,rumination bouts, self grooming and frequency of self grooming were evaluated on -12 hr, -7th day, -14th day and -21st day prepartum for period of 12 hr in a day. Repeated Meausures ANOVA was used for the analysis of the data. Result: It was found that lying time, lying bout duration was significantly more in rubber mattress group as compare to concrete floor. However, 12 hr before parturition standing time was significantly high compare to any other observational day within the group. Similarly, rubber mattress had positive effect on rumination time, lying duration and self grooming frequency as compare to bare concrete floor. It was concluded that rubber mattress had beneficial effect in calving pen of Tharparkar cow during winter season due to its softness and insulating property. It provided comfort and warmth to the parturient cows. which was evident by increase in rumination time, more lying duration and reduced self grooming frequency.

Impact of temperature humidity index (THI) on physiological responses and milk yield of Tharparkar and Karan Fries cows exposed to controlled environment

Tharparkar and Karan Fries cows were exposed to 25°C, 35°C and 42°C with relative humidity of 50±5%, corresponding to THI of 72.2, 85.3 and 91.0, respectively for three hours continuously for three days consecutively in the control climatic chamber. At THI of 91.0, physiological responses i.e. RR/ min, PR/min and RT (°F) increased by 14, 13, and 1.18 in Tharparkar and 23, 14 and 2.98 in Karan Fries cows, respectively over pre exposure values. At THI of 91.0, the surface body temperature was increased over THI 72.2 by 5.21 to 7.52°C in Tharparkar and 7.45 to 8.42°C in Karan Fries cows. Skin blood flow of Karan Fries cows was increased by 4.98, 4.15 and 3.95 PU at THI 85.3 and 6.84, 9.18 and 8.04 PU at 91 THI over the pre exposure values of respective THI at dorsal, ventral and ear part of body, respectively. The decrease in milk yield was calculated in the THI range of 72.2 - 91.0, the milk yield was decrease (per unit increase in THI) by 135.11ml in Karan Fries and 51.60 ml in Tharparkar cows. The results of the study clearly indicated the more sensitivity of Karan Fries compared to Tharparkar cows at higher THI. Therefore, Karan Fries cows needs protection from extreme heat for sustained production performance.

Effect of feeding management practices on water intake in Tharparkar and Rathi cattle of Indian hot arid zone

The present study was conducted to assess the effects of grazing and stall feeding on water intake in Tharparkar and Rathi cattle in their native tract of hot arid zone. Lactating cattle (Tharparkar 10; Rathi 10) and heifers (Tharparkar 10; Rathi 10) of each breed were divided into two groups, forming grazing and stall-fed group at Jodhpur and Bikaner districts of Rajasthan. Observations were recorded for water intake, dry matter intake and milk yield in the morning and afternoon regularly, twice weekly for six weeks during each season (summer, winter and rainy) continuously for two years. Water intake in lactating cows and heifers of both the breeds followed the pattern of THI during summer season. Rathi cows had higher water intake/kg W0.75 than Tharparakar cows, however, Tharparkar heifers had higher water intake/kg W0.75 than Rathi heifers. Grazing Rathi cows had significantly higher water intake than stall-fed cows. Study revealed that Tharparkar cows had lesser water intake per kg W0.75 and per kg milk yield basis; however, Rathi heifers had lesser water intake per kg W0.75 basis in their native tract.

Effect of seasons on physiological responses, milk production and composition in Indigenous cows

The present investigation was carried out to find the effect of seasons on milk production and composition in indigenous Sahiwal, Tharparkar and Gir cows maintained under the intensive management practices at the institute livestock farm. Fifteen lactating cows of Tharparkar (TP), Sahiwal (SW) and Gir breed were selected in early lactation. The experiment was conducted for a period of 10 months and the seasons were categorized as hot-humid, hot-dry, autumn and winter season. Blood and milk samples collected at fortnightly intervals were analysed for minerals and plasma hormones. Physiological responses-respiration rate (RR), pulse rate (PR) and rectal temperatures (RT) were recorded. The results showed that the milk fat, solid not fat SNF and urea levels were higher in TP cows in comparison to SW and Gir cows (p&lt;0.01), however, protein % was lower (p&lt;0.01) in TP cows. Milk Mg, Ca and Na levels were lower in hot-humid season than in winter season (p&lt;0.05) in TP cows in comparison to SW and Gir. Plasma cortisol level was higher and aldosterone level was lower in hot-humid and hot-dry season in all the breeds of cows (p&lt;0.05) than the values observed in winter season. TP cows were found to have higher aldosterone level as compared to SW and Gir cows in all the seasons. The cows response to ambient temperature in terms of RR, RT and PR was higher in hot-humid season and lowest in winter season (p&lt; 0.01) in all the breeds, however changes in RT were of less magnitude in TP cows than SW and Gir cows in hot-hot humid season. It was concluded that TP cows have higher plasma aldosterone, milk urea and sodium levels and less diurnal variation in RT, PR and RR in comparison to SW and Gir cows in hot-dry and hot humid season which makes TP cows more heat tolerant than SW and Gir.

Influence of Genetic and Non-Genetic Factors on Production Traits of Tharparkar Cattle at Organized Farm

Data consisted of 284 performance records belonging to 63 Tharparkar cows completing at least three lactations spread over a period of fifteen years (2002 to 2016) for genetic analysis of milk production traits viz. dry period, lactation length, lactation milk yield, 300 days milk yield, milk yield per day of lactation length and milk yield per day of calving interval. The overall least-squares means were 138.47 ± 3.02 days, 281.71 ± 3.43 days, 2003.29 ± 13.40 kg, 1885.81 ± 23.07 kg, 6.65± 0.10 kg and 4.03 ± 0.04 kg, respectively. Heritabilities ranged from 0.08 to 0.59, genetic correlations between the milk production traits ranged from 0.57 to 0.93 and phenotypic correlations ranged from 0.02 to 0.56. The effect of period of calving on service period, lactation milk yield, three hundred days milk yield and milk yield per day of lactation length; effect of season of calving on lactation length were significant. The random effect of sire was observed to be highly significant (P≤ 0.01) on all the production traits.

Impact of different seasons on the milk somatic and differential cell counts, milk cortisol and neutrophils functionality of three Indian native breeds of cattle

The present study was undertaken to compare the effect of different seasons on the mammary immunity of three Indian native breeds of cows (Tharparkar, Gir and Sahiwal) well adapted to the tropical region. For this milk samples were collected from cows in winter (THI=57, comfortable zone), hot-dry (HD; THI=76, heat stressful zone) and hot-humid (HH; THI = 82, severe heat stress) and estimated for milk somatic cell counts (SCC), phagocytic activity (PA) of milk neutrophils, milk cortisol and heat shock proteins and function associated genes in milk neutrophils. Milk SCC was evaluated using a cell counter and differential cell counts measured microscopically. Cortisol was quantified in skimmed milk by competitive ELISA. Milk PA was estimated using nitro blue tetrazolium assay, and for gene expression studies, milk neutrophils were isolated and studied for heat shock proteins (HSP40, HSP70, HSP90α) and cell adhesion molecules (CD11b, CD25, CD44) using real-time polymerase chain reaction. All the studied parameters increased in HD and HH seasons with highest values observed in Sahiwal cows. However, PA of neutrophil was highest in Tharparkar cows in winter and decreased gradually at higher THI values during hot seasons. Milk cortisol was positively correlated with expression of various CD molecules and HSPs (p < 0.05) in milk neutrophils but negatively correlated (p < 0.05) with PA during HH season in all breeds. The study revealed that Indian native cows were at considerable risk in HH season and Sahiwal cows were more heat stressed followed by Gir and Tharparkar cows, respectively, and thus may require managemental interventions. Also, the higher expression of HSP70 and CD25 with increasing THI levels in hot seasons makes them suitable biological markers for quantifying heat stress.

Effect of Non-Genetic Factors on Disposal Pattern in Tharparkar Cows

Data on 166 Tharparkar cows, maintained at Dairy cattle breeding division of ICAR-National Dairy Research Institute, Karnal (Haryana) during 1991 to 2013 were collected and classified into four period viz., P1 (1991-1995), P2 (1996-2000), P3 (2001-2005) and P4 (2006-2013) of calving and four season viz. Winter, Summer, Rainy and Autumn of calving to study the disposal pattern. Out of total lifetime milk yield, 83.39% in Tharparkar cows was completed upto 5th parity and due to which the analysis upto 5th parity was conducted. Descriptive statistics were computed for analysis of disposal pattern, whereas effect of non-genetic factors on disposal pattern was analyzed using Chi square statistic. The overall disposal in adult cow per lactations basis was (Mortality: 3.33% and culling: 27.78%) but overall disposal upto fifth parity was 29.88% (culling rate: 26.5% and mortality rate: 3.32%). The overall disposal in adult cows was higher in third parity (33.3%) and lowest in fifth parity (24.3%). The effect of calving season on overall disposal rate in third lactation was significant (P

Association of milk quality parameters with teat and udder traits in Tharparkar cows

The present experiment was carried out to study the association of milk quality traits (fat, protein, lactose, solid not fat (SNF), total solids (TS) and somatic cell count (SCC)) with teat traits ((teat length (TL), teat diameter (TD), distance between teats (DbT) and teat tip height from ground (THFG)) and udder traits ((udder circumference= UC, udder depth (UD), udder width (UW) and udder height from ground (UHFG)), in Tharparkar cows. The experiment was carried out on 32 tharparkar cows of different parities and lactation stages. Morning and evening measurement of teat and udder traits was carried out before milking and approximately 30 ml of representative milk samples were taken from each of the functional quarters and one composite milk sample of each experimental animal fortnightly from the date of calving of the animal in clean sampling bottles. Fat% and SNF% showed a negative, significant (P&gt;0.05) to highly significant (P&gt;0.01) correlation with TD, UL and FUD. Protein% expressed a positive, significant (P&gt;0.05) to highly significant (P&gt;0.01) correlation with UC, FUD and DbT. Further, Fat%, SNF% and TS% expressed a positive, significant (P&gt;0.05) to highly significant (P&gt;0.01) correlation with THFG. SCC (×105/ml) showed a positive, significant (P&gt;0.05) to highly significant (P&gt;0.01) correlation with TL, TD, DbT, UC and UL, whereas it had a negative correlation with THFG, rear-udder depth (RUD) and UW. It was further observed that Fat% expressed a positive highly significant (P&gt;0.01) phenotypic correlation with SNF% and TS%. SNF%, Lactose%, Protein% and TS% expressed a negative phenotypic correlation with SCC.

Impact of udder and teat morphometry on udder health in Tharparkar cows under climatic condition of hot arid region of Thar Desert.

Prevention of subclinical mastitis (SCM) is an important tool for sustainable dairying and implementing higher production level in animals. The present investigation involved a total of 397 quarters of milk examination of 105 indigenous Tharparkar cows at Livestock Research Centre, Chandan located in the Jaisalmer district of Rajasthan in Thar Desert to study the impact of udder and teat morphometry on udder health. Udder health was examined by somatic cell count to check the status of subclinical mastitis while udder and teat morphometry of 90 udder and 386 quarters, i.e., udder shape and depth, teat end shape, teat length, and teat diameter were examined at individual animal level and quarter level. Data were collected from the record register maintained at the farm and data evaluated by parity (no. of lactation) and stage of lactation. On analysis of variance, result revealed the significantly (P < 0.05) higher incidence of SCM was for pendulous shape udder in respect of regular udder, as well as for inverted and flat teat end shape in respect of pointed teat end shape. Large teat length and upper depth animals had significantly (P < 0.05) more incidence of SCM as compared to small and medium teat length and udder depth group, respectively. Thick teat diameter group animals were significantly (P < 0.01) more prone to infection as compared to medium and thin teat diameter group animals. So, it can be concluded that selection for optimum udder and teat morphometry in breeding program may help to reduce susceptibility for intramammary infections in Tharparkar cows. Microbiological study of milk samples could be helpful in the nearby future for identification of subclinical mastitis.

Incidence of mastitis and activity of milk neutrophils in Tharparkar cows reared under semi-arid conditions.

Rearing of indigenous Tharparkar (TP) cows (native of arid Thar deserts) under high humid conditions (>75% humidity) has increased the incidence of mammary infections in them. A study was undertaken to see the number, activity, and expression of milk neutrophils isolated from healthy and mastitic cows. There was a significant (P < 0.05) influx in milk somatic cell counts (SCC) and neutrophils in sub-clinical and clinical mastitis cows. No change was observed in the phagocytic activity (PA) of milk neutrophils between healthy and sub-clinical mastitis (SCM) cows, but these activities decreased significantly (P < 0.05) in clinical cases. Chemotactic activity showed a significant difference between all the groups. Lactose varied significantly (P < 0.05) between healthy, sub-clinical, and clinical mastitis (CM) cows. Expression of chemokine receptor (CXCR1) was more in mastitis cows and also higher as compared to CXCR2. No change was observed in cluster of differentiation molecule (CD62L) among all the three groups of TP cows. Expression of interleukin (IL-8) and CD11b was low in healthy cows, increased significantly (P < 0.05) in both sub-clinical and mastitis cows. This study indicates that low producing TP cows are also prone to mammary infections when reared under semi-arid conditions.

Effect of Non-Genetic Factors on Somatic Cell Count in Tharparkar Cows under Hot Arid Region of Thar Desert Area

Effect of Non-Genetic Factors on Somatic Cell Count in Tharparkar Cows under Hot Arid Region of Thar Desert Area

Infradian rhythmicity in milk leukocyte activity together with plasma cortisol and prolactin levels throughout the lactation period in high-yielding crossbred cows

Infradian rhythmicity in milk leukocyte activity together with plasma cortisol and prolactin levels throughout the lactation period in high-yielding crossbred cows has been studied in 10 high-yielding (milk production: 5000 l per lactation) Karan Fries crossbred (Holstein Friesian × Tharparkar) cows. Milk and blood samples were collected from all the experimental animals. Isolation of milk phagocytes (neutrophils and macrophages) and lymphocytes were done by density gradient centrifugation. In vitro phagocytic index of milk neutrophils and macrophages was performed by colorimetric NBT reductive assay. Mitogen-induced milk lymphocyte blastogenic response was estimated by colorimetric MTT (tetrazolium) assay. Total plasma cortisol and prolactin were estimated by enzyme immune assay. Highest value of plasma cortisol and prolactin was observed at calving which decreased significantly (p < 0.01) on 15th day postpartum for both prolactin and cortisol. Immune activity of milk leukocytes was highest on day 0 colostrum and decreased significantly (p < 0.01) on 7th day postpartum. A significant (p < 0.01) rise of plasma prolactin was observed around 135th and 225th days postpartum, whereas a peak level of plasma cortisol was observed at 105th, 180th, and 270th days postpartum. Phagocytic index of milk neutrophils and macrophages remains almost in a steady state during mid-lactation period (between 100 and 200 days postpartum). A decline in increasing trend of milk phagocytic activity was observed during late lactation. Mitogen-induced milk lymphocyte blastogenic response was highest on day 0 colostrum which decreased significantly (p < 0.01) on 15th day postpartum. Con A-induced milk lymphocyte blastogenic response showed an increasing trend from 120th to 210th days postpartum. Upon correlation study, it showed that the plasma cortisol has a negative effect on milk leukocyte activity, while prolactin has a positive effect, though the effect is lactation stage specific.

EFFECT OF WEANING ON MILKING BEHAVIOUR, PRODUCTION AND REPRODUCTION OF INDIGENOUS THARPARKAR CATTLE

The present study was conducted to see the effect of weaning on the performance of newly calved Tharparkar cattle reared at Cattle & Buffalo Farm (Livestock Production and Management Section), Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh (India). A total of 14 Tharparkar cows were selected as per their due date of calving and randomly divided into two equal groups i.e. Group S (Suckling) and Group W (Weaned). The animals in the weaning group (n=7) were isolated from their calves just after calving and animals in suckling (n=7) group were allowed to suckle twice daily. Various parameters were observed like milking temperament, milking behaviour traits i.e. let down time, milk flow rate, milking time; productive and reproductive performance. The temperament score of weaning system (2.45±0.18) was higher than sucking system (2.22±0.23). There was highly significant effect (P≤0.01) on milking behavioural traits as the daily yield per milking, milking time and milk flow rate were lower in weaned as compared to suckling whereas let down time of weaned was higher than suckled counterparts. The daily milk yield and total milk yield were higher for suckling group. The overall mean for days to express first heat after calving was more for suckling (69.40±22.03 days) as compared to weaned (42.86±10.29 days) whereas service period was 109.00 d v/s 82.33±11.84 d. Present findings provide baseline information on weaning system of rearing of Indigenous native breed of cattle. Weaning in indigenous cattle can be done but it should be practiced judiciously with giving due care to the welfare of animal and their calves.

Body Conformation in Tharparkar Cattle as a Tool of Selection

For present investigation, Tharparkar cows available at Cattle and Buffalo Farm, Indian Veterinary Research Institute, Izatnagar (U.P.) were used. Body conformation scoring was done as per modified International Committee on Animal Recording (2012). Measurements were taken in centimeter (cm) before morning milking and prior to any feed intake using graduated measuring stick, vernier caliper and flexible meter tape. In Tharparkar cattle, the average score points (ASP, under 1–9 point scale score system) for body conformation traits like stature (5.02: intermediate), chest width (4.71: intermediate), body depth (4.75: intermediate), angularity (5.60: intermediate), rump angle (5.55: intermediate), rump width (4.80: intermediate), rear leg rear view (7.39: parallel), rear leg set (5.27: intermediate), foot angle (7.09: steep), fore udder attachment (6.44: strong), fore teat placement (3.80: intermediate), teat length (4.71: intermediate), udder depth (5.71: intermediate), rear udder height (3.46: intermediate), central ligament (5.27: intermediate), rear teat placement (5.82: intermediate), locomotion (7.20: no abduction), hock development (7.28: dry), bone structure (6.64: fine and thin), rear udder width (5.64: intermediate), teat thickness (2.61: narrow), muscularity (6.00: intermediate), hump size (3.98: intermediate), dewlap size (5.04: intermediate) and naval flap size (3.09: intermediate) were assessed. Most of the body conformation traits in Tharparkar cows were of intermediate nature and of desirable type, moreover, some traits also showed the presence of undesirable ASP, which expressed scope for further improvement. Thus, present investigation gave explicit clue to bring Tharparkar cattle at par with other exotic breeds, if little effort is made to incorporate these conformation traits in selection program.

Climatic effects on occurrence of clinical mastitis in different breeds of cows and buffaloes

The study was conducted to find out the effect of different seasons on incidence of mastitis throughout the year in Indigenous cows, crossbred cows and Murrah buffaloes. Lactation records pertaining to the 12 year period were collected and incidence of mastitis was plotted against the climograph of the Karnal zone, Haryana, India. The hot humid climate was found to adversely affect the incidence of mastitis in all the breeds of cows and Murrah buffaloes. The incidence was significantly affected by the season (p<0.01) in all the breeds, however incidence was lowest in Murrah buffaloes in comparison to cows. Further incidence was more in Sahiwal and Tharparkar cows (p<0.01) than the crossbred Karan Swiss and Karan Fries cows. The increase in temperature humidity index resulted in increased incidence of mastitis in cows (p<0.01) but Murrah buffaloes were less affected.

Effect of urea supplemented and urea treated straw based diet on milk urea concentration in crossbred Karan-Fries cows

The study was undertaken to evaluate the effect of urea supplemented and urea treated straw based diet on milk urea concentration. Six multiparous crossbred Karan-Fries (Holstein Friesian × Tharparkar) cows were blocked into three groups of nearly equal body weight, DIM, milk yield and milk fat content and were randomized into a 3 × 3 Latin square design with 3-week period. Three experimental diets were fed to the animals. Composition of these diets were: Diet 1) green maize, wheat straw and concentrate mixture; Diet 2) green maize, wheat straw, concentrate mixture (urea supplemented) and molasses; Diet 3) green maize (4 % of total DM), 4 % urea treated wheat straw and concentrate mixture. Intake of DM and CP did not vary across the diets. Intake of digestible crude protein (DCP) was found significantly higher in diet 2, while ME and NEl intakes were found significantly lower in diet 3 but did not differ between diets 1 and 2. Average milk and plasma urea concentrations (mg dl-1) were found 29.2 ± 2.6, 45.3 ± 0.9, 34.5 ± 2.3 and 28.9 ± 2.4, 36.6 ± 1.4, 33.9 ± 2.2, respectively in diet 1, diet 2 and diet 3. Urea concentrations in morning milk samples were found significantly lower than noon or evening samples in all the three diets. Concentrations of urea in milk and plasma were found closely correlated (r = 0.94) and the regression equation developed was, plasma urea = 8.90 (.89) + .79 (.02) milk urea. Intake (g) of DCP than CP, per unit (MCal) of ME was found more closely associated with milk urea concentration. The study revealed that urea supplementation and urea treated straw based diet increased urea concentration significantly in milk and plasma. Morning milk urea values that estimated at a time gap of 15 hr since last major feeding may be considered as the lowest level and can be used for interpretation to monitor feeding adequacy or reproductive performances in dairy cows.