|Livestock Research for Rural Development 27 (3) 2015||Guide for preparation of papers||LRRD Newsletter||
Citation of this paper
The objective of the study was to evaluate the productive and reproductive performance of Murrah, Surti, Nili-Ravi buffaloes and their crosses in a large scale farm in the intermediate zone of Sri Lanka. Records on age at first calving (AFC), calving interval (CI), lactation length (LL), dry period (DP), lactation number (LNO), total milk yield per lactation (TMY), and birth weight (BW) were collected for the period of 1993-2013 from history sheets maintained at the farm. Animals were maintained under semi intensive management system. Data were analyzed using GLM procedure in SAS. The overall least square means (±S.E) for total milk yield, lactation length, calving interval and birth weight were 1185 ± 21.4 kg, 268 ± 2.55 days, 470 ± 4.87 days, and 27.7 ± 0.13 kg, respectively.
The least square means (±SE) for age at first calving and dry period were 48.2 ± 0.30 months and 179 ± 4.43 days, respectively. Total milk yield was not influenced by genetic and non genetic factors. Lactation length was influenced by year of calving (YOC), year of dry off (YOD), season of calving (SOC), dry period and sex of calves. Calving interval was influenced by breed and parity. Birth weight was influenced by breed and year of calving. Age at first calving was influenced by breed and year of calving. Dry period was influenced only by lactation length. It could be concluded that there were no breed differences for the traits milk yield, lactation length and dry period. For the traits birth weight, age at first calving and calving interval Murrah crosses perform better than the other breeds at the Melsiripura farm. Performance of the breeds could be improved through planned breeding and selection, improved feeding, housing and health care management.
Key words: genotype, productive traits, reproductive traits
The dairy sector has been identified as the priority sector for economic development among other livestock sub sectors in Sri Lanka. In the year 2012 the gross domestic product (GDP) contribution of livestock sector to the agriculture GDP was 0.8% (Central Bank of Sri Lanka 2012).
In the year 2012 the contribution of buffalo and neat cattle to the nation’s total milk production was 21% and 79%, respectively (Department of Census and Statistics 2012). But buffalo has a great potential to contribute to domestic milk production if managed appropriately. River type breeds such as Murrah, Surti and Nili-Ravi have been imported from India and Pakistan to upgrade the production potential of Lankan buffaloes. The majority of the buffaloes are distributed in the dry zone especially in the districts of Anuradhapura, Polonnaruwa, Batticaloa and Ampara.
Buffalo can efficiently convert low quality feed stuff like straw and agro-industrial waste into human food, improve soil structure through bio-fertilizer and as a financial asset which can be sold when needs arise (Pasha and Hayat 2012). However, some factors affecting productivity are of paramount importance to agricultural economics in this region of the world. Reproductive efficiency is the primary factor affecting productivity and is hampered in female buffalo by an inherent late maturity, poor estrus expression in summer, distinct seasonal reproductive patterns, and prolonged inter calving intervals (Madan 1988). Productive and reproductive traits of imported breeds and their crosses under Sri Lankan condition have not been studied using long term performance records.
Hence, the current study was planned to evaluate the productive and reproductive performance of Murrah, Surti and Nili-Ravi buffaloes and their crosses at a large farm in the intermediate zone of Sri Lanka and to study the various factors affecting productive and reproductive performance of these breeds.
Melsiripura National Livestock Development Board (NLDB) farm is located in Kurunegala district of northwestern province with an altitude of 116 meters above sea level. The soil of this region is red yellow Podzolic, and the reaction is usually moderate to strongly acidic with a trend towards increasing acidity with increasing rainfall. The organic matter and nitrogen status is medium and increases with elevation. Phosphorus and potassium status is usually low. The depth, texture and drainage are extremely good. The average annual rainfall of Melsiripura farm is 1600 mm, the mean temperature is 29ºC and the humidity ranges from 75% to 80%.
Different types of pasture and fodder are cultivated in the farm. The pasture land consists Brachiaria brizantha and the fodder consists of Guinea A, Guinea B, Napier, CO3 and gliricedia. Animals were maintained under semi intensive system and they were allowed for grazing in the field from 7:30am – 12:30pm. In addition concentrates also were given. Buffaloes had access to water sources for wallowing in the afternoons (1.00-3.00 pm).
Natural service was practiced using a male: female ratio of 1:60. Bulls were rotated every week. Bull calves for breeding purpose were selected according to set criteria and surplus bull calves were sold.
There were six buffalo breeds maintained at the farm viz. Murrah, Nili Ravi, Surti, Murrah crosses, Nili Ravi crosses and Surti crosses. But the breed composition varied with time. During the period of data collection majority of the animals at the farm were Murrah crosses.
Data for this study comprised 570 performance records of 244 buffalo cows of different breeds for a period of 1993 to 2013. Data on six buffalo breeds were available at the farm ; the breeds Murrah, Nili Ravi, Surti, Murrah crosses, Nili Ravi crosses and Surti crosses were assigned the numbers 1, 2, 3, 4, 5 and 6, respectively.
The number of animals of each breeds group were 22, 6, 20, 73, 105 and 18, respectively. Performance records were extracted from history sheets maintained at the farm. Information extracted were animal identification number, sire identification number , dam identification number, calving date, lactation number, date of dry off, birth weight of calf, sex of calf, lactation length and total milk yield. Lactation length less than 90 days was not included for analysis. The traits studied were age at first calving, calving interval, lactation length, dry period, lactation number, total milk yield and birth weight.
The season of calving (SOC) and season of dry off (SOD) were divided into four classes viz. season one (January to March), season 2 (April to June), season 3 (July to September), and season 4 (October to December). Year of calving was grouped into 5 classes at 4 years interval, starting from 1993 to 2013. Year of dry off also was grouped same as the year of calving starting from 1994 to 2013.
Age at first calving was computed from the number of days from birth to the date of first calving. Age at first calving was grouped into three classes; the classes were 32-36 months (class 1), 37-40 months (class 2) and above 40 (class 3).
Calving interval was grouped into four classes; 10-12 months (class 1), 13-15 months (class 2), 16-18 months (class 3) and above 18 (class 4).
Lactation length was grouped into seven classes. Class one comprised the lactation length of 90 -150 days and subsequent classes were formed with 50 day class interval while seventh class comprised the lactation length more than 400 days. Lactation number was grouped into six classes from first to fifth lactation and the sixth group comprised lactation number greater than five.
Dry period was computed from the period between date of dry off and subsequent calving. Dry period was grouped into 4 classes; class one comprised buffaloes having dry period up to 60 days, 60-90 days ( class 2), 90-120 days (class 3) while cows having dry period greater than 120 days were assigned to class 3.
Birth weight was grouped into four classes, class one comprised birth weight less than 20 kg , 20-24 kg (class 2), 25-29 kg (class 3) and birth weight >29 kg grouped into class 4. Table 1 gives the definitions of the different traits studied.
|Table 1. Traits studied and their definitions|
|Age at first calving (AFC) (Months)||Interval between date of birth to the date of animal’s first calving.|
|Calving interval (CI) (Days)||Interval between two successive calving.|
|Lactation length (LL) (Days)||Interval between date of calving to date dry off.|
|Calving to service period (CSP) (Days)||Interval between date of calving to subsequent conception.|
|Dry period (DP) (Days)||Interval between date of dry off to subsequent calving|
|Lactation number (LNO)||Number of calving|
Data were entered and analyzed using Microsoft Excel and SAS 9.1. GLM procedure was used to analyze the data and mean separation was done using LSD.
The statistical model used was:
Yijklmnpq= µ + Bi + Sj + LNOk +DPl+LLm+SOCn+YOCp+YODq+eijklmnpq
Where Yijklmnpq was the observation; µ was an underlying constant; Bi was the fixed effect of ith breed; Sj was the fixed effect of jth sex; LNOk was the fixed effect of kth lactation number; DPl was the fixed effect of the lth dry period; LLm was the fixed effect of mth lactation length; SOCn was the fixed effect of nth season of calving; YOCp was the fixed effect of pth year of calving; YODq was the fixed effect of qth year of dry off; eijklmnpq was a common random error associated with each observation.
Tables 2 to 7 show the raw mean of productive and reproductive traits of six breeds of buffalo. Traits with high co-efficient of variation shows that improvement of these traits could be achieved through selection and planned breeding.
|Table 2. Summary of the performance of Murrah breed at the farm|
|Age at first calving (months)||22||61.5||12.0||19.5|
|Calving interval (days)||92||479||140||29.2|
|Birth weight (kg)||109||27.7||2.94||10.6|
|Lactation length (days)||112||298||70.1||23.6|
|Dry period (days)||98||180||141||78.1|
|Total milk yield (kg)||113||1249||542||43.4|
|Table 3. Summary of the performance of Nili- Ravi breed at the farm|
|Age at first calving (months)||6||44.3||3.89||8.77|
|Calving interval (days)||24||412||91.6||22.2|
|Birth weight (kg)||29||28.8||3.80||13.2|
|Lactation length (days)||30||238||78.8||33.2|
|Dry period (days)||27||181||96.2||53.2|
|Total milk yield (kg)||30||1187||543||45.7|
|Table 4. Summary of the performance of Surti breed at the farm|
|Age at first calving (months)||20||43.7||7.81||17.9|
|Calving interval (days)||123||489||137||28.0|
|Birth weight (kg)||143||28.4||2.40||8.43|
|Lactation length (days)||144||287||56.7||19.7|
|Dry period (days)||127||185||154||83.1|
|Total milk yield (kg)||145||1197||508||42|
|Table 5. Summary of the performance of Murrah crosses at the farm|
|Age at first calving (months)||73||44.9||6.31||14.1|
|Calving interval (days)||137||419||111||26.4|
|Birth weight (kg)||191||27.5||3.28||12|
|Lactation length (days)||203||229||64.6||28.2|
|Dry period (days)||165||173||88.5||51.3|
|Total milk yield (kg)||208||1112||511||46|
|Table 6. Summary of the performance of Nili-Ravi crosses at the farm|
|Age at first calving (months)||105||46.7||5.31||11.4|
|Calving interval (days)||102||476||146||30.1|
|Birth weight (kg)||130||27||2.93||10.9|
|Lactation length (days)||143||260||80.1||30.8|
|Dry period (days)||111||221||131||59.2|
|Total milk yield (kg)||146||1094||505||46.2|
|Table 7. Summary of the performance of Surti crosses at the farm|
|Age at first calving (months)||18||48.8||6.74||13.8|
|Calving interval (days)||260||477||127||26.6|
|Birth weight (kg)||320||27.2||3.20||11.8|
|Lactation length (days)||329||280||80||28.5|
|Dry period (days)||282||199||122||61.4|
|Total milk yield (kg)||334||1211||499||41.2|
Table 8 shows the effect of different factors on reproductive and productive traits of buffalo breeds.
|Table 8. Summary of analysis of variance of different traits of Murrah, Surti, Nili-Ravi, and their crosses at Melsiripura farm|
|Source||Df||TMY (P)||LL (P)||BW (P)||CI (P)||AFC (P)||DP (P)|
|Age at first calving||2||0.80||0.35||0.60||0.08||-||0.06|
|Season of calving||3||0.23||0.01||0.47||0.10||0.76|
|Year of calving||4||0.84||0.01||0.03||0.66||0.40|
|Season of dry off||3||0.89||0.74||0.44||0.06||-||0.12|
|Year of dry off||4||0.91||0.02||0.26||0.21||-||0.52|
|Df- degree of freedom, P- probability value, TMY- Total milk yield, LL- Lactation length, CI- Calving interval, BW- Birth weight, AFC- Age at first calving, DP- Dry period.|
The overall least square mean with standard error and co-efficient of variation of different traits of Murrah, Surti, Nili-Ravi, and their crosses at Melsiripura farm are summarized in Table 9. Higher co-efficient of variation for the traits of milk yield and dry period reveals that these traits could be improved through selection or rigorous culling.
|Table 9. Summary of least square means and co-efficient of variation of different traits of Murrah, Surti, Nili-Ravi, and their crosses at Melsiripura farm|
|Source||N||LS Mean ± SE||CV%|
|Age at first calving(months)||244||48.2 ± 0.30||16.0%|
|Calving interval(days)||570||470 ± 4.87||24.7%|
|Birth weight(kg)||570||27.7 ± 0.13||10.8%|
|Dry period (days)||570||179 ± 4.43||59.1%|
|Lactation length(days)||570||268 ± 2.55||22.7%|
|Total milk yield(kg)||568||1185 ± 21.4||43.0%|
|N Number of observations, SE standard error, CV coefficient of variation|
Milk yield was not influenced by breed, age at first calving, calving interval, parity, dry period, lactation length, sex of calf, season of calving, year of calving, season of dry off, and year of dry off (Table 8).The least square mean for total milk yield was 1185 ± 21.4 liters per lactation (Table 9). This value was close was close to the findings of Jain and Kothari (1983) (1127 kg) in India, Tailor et al (1992) (1121kg) in India and Shrinivaset al (1997).
But present mean was lower than those reported by Rao and Nagarcenkar (1977) and Bhat et al (1980) (1813 kg); and Dhar and Deshpande (1995) (1704.36 kg) in India for Murrah.Higher values were also reported by Rao and Nagarcenkar (1977), Bhat et al (1980), (1765 kg) in India for Nili-Ravi buffalo.
While lower estimates of lactation milk yield were reported by Cheng (1984) (778 kg) in China, for Swamp buffaloes. The differences in total milk yield may be due to differences in nutritional and managerial practices and changes in environmental factors during different period of the year or over a period of time. Higher values of milk yield than the present value obtained in India reveals that milk yield in Sri Lanka could be increased if appropriate measures were taken to provide the optimum feeding, housing and health care management to these animals.
Milk yield was not significantly influenced by breed, age at first calving , calving interval , parity, dry period , lactation length , sex of calf, season of calving , year of calving , season of dry off and year of dry off . The absence of breed differences may be attributable to the fact that all the breeds in the farm were treated alike. Breed differences could be realized if the breeds were managed separately and their requirements were met appropriately. Sastry and Tripathi (1998) in India reported that integrating various aspects such as improved housing, nutrition, breeding and milking together are known to produce remarkable improvements in productive performance of buffaloes.
The least square mean for lactation length in the present study was 268 ± 2.55 days (Table 9). Lactation length was influenced by year of calving, dry period, sex of calf, season of calving and year of dry off (Table 8). The least square mean for lactation length in the present study was similar to the values reported by Jain and Kothari (1983) (266 days) for Surti buffaloes in India; Tajane and Siddiquee (1985) (256 days) for Mehsana buffalo in India, Dhar and Deshpande (1995) (256 days) for Murrah buffaloes in India and Afzal et al (2007) (273 days), for Nili-Ravi in Pakistan.
However, mean slightly higher than the present study were reported by Chaudhry (1992) (302 days), Dass and Sadana (2000) (313 days) for Murrah. Longer lactation length could be obtained through improved management and appropriate selection or culling practices.There was a reduction in lactation length from year of calving 1 to year of calving 5 (Table 10). However, the lactation length of 326 and 343 observed for year of calving 1 and year of calving 2 were greater than the optimum length expected to have the optimum calving interval of 365 days. The reduction in lactation length for different year of calving may be due to differences in climatic factors and/or differences in management practices in the farm. The effect of year of calving on lactation length was in agreement with the results reported by Jawarkar and Johar, (1975), and Gurnani et al (1976) in India.
There was a reduction in lactation length with increasing dry period. The longest lactation length was observed for the optimum dry period of less than 60 days. Dry period longer than the optimum period is an indication of improper management which could be the reason for reduced lactation length with increased dry period.
There was a reduction in lactation length from season 1 to season 4. This may due to the influence of season on the quantity and quality of the pasture and fodder availability.
Lactation length was influenced by year of dry off. The longest lactation length was observed for class 5 and the shortest lactation length was observed for class one.
In the present study, cows with female calves had longer lactation length than cows with male calves.
|Table 10. Effect of different factors on lactation length of buffaloes|
|N||LS means + SE||Class
|N||LS means + SE|
|1||15||326± 49.6a||1||17||257± 46.1a|
|2||81||344± 30.7ab||2||90||229± 29.7ab|
|3||197||282± 28.6ac||3||187||290± 28.5ac|
|5||178||202± 42.0ace||5||161||323± 42.9a|
|1||25||299± 14.6a||1||287||277± 8.42a|
|2||54||292± 11.2ac||2||283||289± 8.50b|
The least square mean for calving interval was 470 ± 4.87 days (Table 9). This value is in agreement with the values reported by Hussain et al (2006) (473.72 days) for Nili-Ravi buffaloes in India. However slightly higher mean value was observed by Shafique and Usmani (1996) (482 days) and Thevamanoharan, (2002) (496 days) in India. Slightly lower values were observed by Komore et al (1994) (453 days) in Sri Lanka and Banik and Tomar (2003) (453 days) for Murrah buffaloes in India.Hussain et al (2006) in India reported that, the calving interval in farm animals is mainly determined by service period.
Although higher and lower values for calving interval than the values reported at present is quoted in the literature, the current value of 470 ± 4.87 days is much longer than the optimum value expected for buffaloes. Therefore effort must be taken to reduce the calving interval through better management both nutrition and breeding.
Nili Ravi had the shortest calving interval but the differences between Nili Ravi and Murrah were not significant and differences between Nili Ravi and Surti were significant. Among the crosses Murrah crosses had the shortest calving interval however; the differences between Nili Ravi and Surti crosses were not significant. But the Murrah crosses had significantly lower calving interval than Nili Ravi crosses (Table11).
There was a general trend of reduction in calving interval with increase in lactation number (Table 11). The significant effect of parity on calving interval was reported by Lundstrom et al (1982) in Sri Lanka for Murrah buffalo and Hussain et al (2006) for Nili-Ravi buffaloes in India. The reduction in calving interval with increasing lactation may be due to increase in performance of cows with age.
|Table 11. Effect of different factors on calving interval of buffaloes|
|N||LS means + SE||Class
|N||LS means + SE|
|1||76||477 ± 22.4a||2||161||513 ± 19.3a|
|2||22||430 ± 33.8ab||3||139||486 ± 20.2ac|
|3||107||505 ± 19.5acd||4||110||457 ± 21.3b|
|4||99||440 ± 27.2ae||5||78||464 ± 22.7b|
|5||68||501 ± 26.9ac||6||82||431 ± 25.4bd|
|6||208||468 ± 20.0a|
|1- Murrah, 2- Nili-Ravi, 3- Surti, 4- Murrah crosses, 5- Nili-Ravi crosses, 6- Surti crosses(P<0.05)|
The least square mean for birth weight was 27.7 ± 0.13 kg with co-efficient of variation of 10.84% (Table 12). Misra et al (1970) in India reported similar value of 26.8±1.04 Kg for Murrah buffaloes during the normal breeding season. However, mean slightly higher than the value of present study was reported by Komori et al (1994) (29.6 kg) and Kansana and Sinniah (2012) (30.29 kg) for Nili-Ravi buffaloes in Sri Lanka.
Birth weight was significantly influenced by breed. Current observation is in agreement with the results reported by Misra et al (1970) in India.
Nili-Ravi had the highest birth weight than Surti and Murrah. As far as the crosses were concerned Murrah crosses showed the highest birth weight than the other two crosses and the differences between these crosses were not significant (Table 12).
There was a significant reduction in birth weight from class one to class three of year of calving . The differences among class three to class five were not significant (Table 12). The change in birth weight with year of calving is attributable to change in feeding regimes and management and environmental factors over the years.
Significant effects of year of birth on birth weight of buffaloes were reported by Thevamanoharan et al (2001) and Akhter et al (2012) in Pakistan.
|Table 12. Effect of different factors on birth weight of buffaloes|
|N||LS means + SE||Class
|N||LS means + SE|
|1||76||28.5 ± 0.55a||1||15||30.7 ± 2.48a|
|2||21||31.2 ± 0.84bc||2||81||30.4 ± 1.55ab|
|3||106||28.3 ± 0.46d||3||197||27.4 ± 1.43ac|
|4||99||29.1 ± 0.67de||4||99||27.1 ± 1.97a|
|5||67||27.6 ± 0.67df||5||178||28.1 ± 2.12a|
|6||201||27.8 ± 0.49df|
|1-Murrah, 2- Nili- Ravi, 3- Murrah crosses, 4- Nili-Ravi crosses, 5 - Murrah crosses, 6- Surti crosses (P<0.05)|
The least square mean for age at first calving was 48.2 ± 0.30 months with co-efficient of variation of 16% (Table 9). Age at first calving was significantly influenced by breed and year of calving.
Age at first calving was significantly influenced by breed. Murrah had the significantly longest age at first calving than Surti and Nili Ravi but the differences between Nili- Ravi and Surti were not significant. As far as the crosses were concerned Surti crosses showed the longest age at first calving than the other two crosses and the differences between Murrah crosses and Nili Ravi crosses were not significant (Table 13).
Table 13. Effect of different factors on age at first calving of buffaloes
LS means ±SE
59.8 ± 1.69 a
44.8 ±3.16 b
44.0 ±1.73 bc
45.9 ±0.93 be
47.0 ±1.18 b
49.2 ±0.89 bdf
The least square mean for age at first calving was 48.2 ± 0.30 months was similar to the values reported by Cady et al (1983), Khan et al (1997) (48.8 months) in Pakistan and Kansana and Sinniah (2012) (49.27 months) for Nili-Ravi buffaloes in Sri Lanka.
However, slightly lower mean values were reported by Prakash et al (1988) (43 months) for Egyptian buffaloes, Singh and Rathi (1990) (40 months) in India for Murrah buffaloes and Naqvi and Shami (1999) (43 months) for Nili-Ravi buffaloes in Pakistan.
Higher mean value was observed by Moore et al (1990), for Nili-Ravi buffaloes (55 months), and Shresta and Yazman (1990) for Murrah (52.3 months). The shorter the age at first calving, the longer will be the productive life (Usmani et al 1987). Bhatti et al (2007) stated that selection for higher milk yield is likely to have a favorable impact on age at first calving. Yet, the age at maturity in buffalo can be reduced to 2 years, with better feeding and management.
Age at first calving was significantly influenced by breed. Khan et al (1997) reported that genetic differences among breeds do exist for this trait, but nutritional and managerial factors are also responsible for the breed differences.
The least square mean for dry period was 179 ± 4.43 days with co-efficient of variation of 59.1% (Table 9). Dry period was significantly influenced by lactation length (P<0.05).
Higher dry periods were observed in class 1, 2, 6 and 7 but the differences between these classes were not significant (Table 14). The lowest dry period was observed in class 4 (250-300).
The least square mean for dry period was 179 ± 4.43days. Slightly lower mean value was observed by Verma and Yadav (1989) (120 days) for Nili-Ravi in India.
Higher mean values were observed by Jain and Kothari (1983) (221 days), Govindaiah and Rai (1987) (288 days) for Surti buffaloes in India. Dry period is most essential as rest period while longer dry period affects the economics of the dairying as the animal is practically unproductive during this period (Kalyankar and Gujar 2002). Appropriate measures should be taken to restrict the dry period below sixty by improved management practices including controlled breeding or through rigorous culling for unrealistically longer dry period.
|Table 14. Effect of different factors on dry period of buffaloes|
|N||LS means +SE|
|1||24||269 ± 25.4a|
|2||75||249 ± 17.3c|
|3||119||196 ± 15.3bde|
|4||175||180 ± 14.4bdg|
|5||121||187 ± 15.4bdi|
|7||16||234 ± 29.6|
|LL- lactation length, N- Number of observations|
Authors express their sincere thanks to the Chairman and General Manager of NLDB, Sri Lanka for granting permission them to collect data from Melsiripura farm. They also express their sincere gratitude to Assistant Manager, Dairy supervisor and staff of the Melsiripura farm for their assistance during the process of data collection.
Afzal M, Anwar M, and Mirza M A 2007 Some factors affecting milk yield and lactation length in Nili-Ravi buffaloes. Pakistan Veterinary Journal 27(3), 113- 117.
Akhtar P, Kalsoom U, Ali S, Yaqoob M, Javed K, Babar M E, Mustafa M I and Sultan, J I 2012 Genetic and phenotypic parameters for growth traits of Nili-Ravi buffalo heifers in Pakistan. The Journal of Animal and Plant Sciences 22(3), 347- 352.
Banik S and Tomar S S 2003 Total determination of calving interval by path analysis in Murrah buffaloes. Indian Journal of Animal Research 37 (1), 19 – 23.
Bhatti S A, Sarwar M, Khani M S and Hussain S M I 2007 Reducing the age at first calving through nutritional manipulation in dairy buffaloes and cows: A review. Pakistan Veterinary Journal 27(1), 42-47.
Bhat P N, Bhat P P, Khan B U, Goswami O B and Singh B 1980 Proc. SABRAO Workshop of Animal Genetic Resources in Asia and Oceania. TARC, Japan pp. 119-199.
Cady R A, Shah S K, Schermerhorn E C and McDowell R E 1983 Factors affecting performance of Nili-Ravi buffaloes in Pakistan Journal of Animal Science 66: 578-586.
Central Bank of Sri Lanka 2012 Annual Report Central Bank of Sri Lanka, Colombo. http://www.cbsl.gov.lk/pics_n_docs/10_pub/_docs/efr/annual_report/AR2012/English/6_Chapter_02.pdf
Chaudhry M A 1992 Factors affecting the lactation length and milk yield in Nili-Ravi buffaloes. Asian-Australian Journal of Animal Science 5, 375-382.
Cheng P 1984 Livestock breeds of China. FAO Animal Production and Health Paper No. 46. FAO, Rome.
Dass G and Sadana D K 2000 Factors affecting some economic traits in Murrah buffaloes. Indian Journal of Animal Research 34, 43-45.
Department of Census and Sattiatics 2012 Sri Lanka. http://www.statistics.gov.lk/agriculture/Livestock/LivestockPopulationSubnational.html
Dhar Y M and Deshpande 1995 Genetic studies on lactation milk yield and lactation length in Murrah buffaloes. Indian Journal of Dairy Science 48(2), 164-166.
Govindaiah M G and Raj A V 1987 Effect of month of calving on lactation parameters in Surti buffaloes. Indian Journal of Dairy Science 39, 226.
Gurnani M, Nagarcenkar R, Gupta S K and Singh A 1976 Seasonality of calving and its influence on economic characters of Murrah buffaloes, Indian Journal of Dairy Science 29, 173-178.
Hussain Z, Javed K, Hussainn S M I and Kiyani G S 2006 Productive performance of Nili-Ravi buffaloes in Azad Kashmir, Pakistan Journal of Animal and Plant Science 16,1-2.
Jain L S and Kothari M S 1983 Factors affecting the production traits in medium sized buffaloes. Indian Journal of Dairy Science 53 (10), 1159-1161.
Jawarkar K V and Johar K S 1975 A genetic study on milk yield of Murrah buffaloes. Indian Veterinary Journal 52, 426-430.
Kalyankar S D and Gujar B V 2002 Some characteristics of buffalo production- A review, Agriculture Review, 23(3)185-193.
Kansana H and Sinniah J 2012 Productive and Reproductive Performance of Nili Ravi Buffaloes at the Nikawaratiya Farm in the Intermediate Zone of Sri Lanka. In: Proceedings of the 2012 Jaffna University International Research Conference (JUICE) (Abstr.).
Keshary K R and Shrestha N P 1980 Proc. SABRAO Workshop in Animal Genetic Resources in Asia and Oceania. TARC, Japan, pp. 423-433.
Khan M S, Shook G E, Asghar A A, Chaudhary M A and Mcdowell R E 1997 Genetic Parameters of milk yield and Adjustment for age at calving in Nili-Ravi buffaloes. American Journal of Applied Sciences 10(5), 505-509.
Komori M, Perera E R K, Perera A N F, and Rajaguru A S B 1994 Productive and reproductive performances of Nili-Ravi Buffaloes in Sri Lanka. J. National Science Council of Sri Lanka 22(2), 201- 211.
Lundstrom K, Abeygunawardena H, Dei Slva L N A and Perera B M A O 1982 Environmental influence on calving interval and estimates of its repeatability in the Murrah buffalo in Sri Lanka, Animal Reproductive Science 5(2), 99-109.
Madan M L 1988 Status of reproduction in female buffalo. In: Buffalo Production and Health: a compendium of latest research information based on Indian studies. ICAR Publication, New Delhi, India pp 89-100.
Misra B S, Raizada B C and Tewari R B L 1970 Gestation length, birth weight of calves and body weight changes during pregnancy in buffaloes bred during summer. Indian Journal of Animal Science 40, 103-109.
Moore R K, Kennedy B W, Schaeffer L H and Moxley J E 1990 Relationship between reproduction traits, age and body weight at calving and days dry in first lactation Ayrshires and Holsteins. Journal of Dairy Science 73 , 835-842.
Naqvi A N and Shami S A 1999 Age at first calving in Nili-Ravi buffalo. Pakistan Journal of biological science 2(2), 438- 441.
Pasha T N and Hayat Z 2012 Present Situation and Future Perspective of Buffalo Production in Asian Journal of Animal and Plant Science 22(3), 250-256.
Prakash A, Tripathi V N and Tomar S S 1988 Relative importance of age and weight at calving on milk production in Murrah buffalioes, Indian Journal of Dairy Science, 41:129.
Rao M K and Nagarcenkar R 1977 Potentialities of the buffalo. World Review of Animal Production 13: 53-62.
Sastry N S R and Tripathi V N 1998 Modern management innovations for optimizing buffalo production. Buffalo production and health, A compendium of latest research information based on Indian studies. 2nd World Buffalo congress, New Delhi 1988, Indian Council of Agricultural Research New Delhi, 38- 62.
Shafique P and Usmani R H 1996 Reproductive performance and milk production of Nili-Ravi buffaloes maintained under Barani (Rain-fed) Areas of Punjab. Pakistan Veterinary Journal 6(4), 168 - 171.
Shrestha N P and Yazman J A 1990 Performance of Murrah and native X Murrah crossbred buffaloes in Nepal, proceeding. Second World Buffalo congress India 2 , 28-33.
Shrinivas J, Govindaiah M G and Jayashankar M R 1997 Genetic studies on first lactation performance of Surti Buffaloes. Buffalo Bulletin, 16 :3.
Singh S and Rathi S S 1990 Relationship among the various reproduction and production efficiency traits in Murrah buffaloes. International Journal of Tropical Agriculture 8, 93.
Tailor S P, Jain L S and Tusavara 1992 Genetic studies on lactation length and dry period in Surti buffaloes. International Journal of Animal Science 7(1), 115-117.
Tajane K R and Siddiquee G M 1985 Adjustment for effects due to parity and year of calving on lactation production in Mehsana buffaloes. Indian Journal of Animal Science 55(1), 71-72.
Thevamanoharan K 2002 Genetic analysis of performance traits of swamp and Riverine buffalo, Ph. D Thesis, Katholieke University Leuven, Belgium.
Thevamanoharan K, Vandepitte W, Mohiuddin G and Chatalakhana C 2001 Environmental factor affecting various growth traits of Swamp buffalo calves. Pakistan Journal of Agricultural Science 38, 5-10.
Usmani R H, Lewis G S and Naz N A 1987 Factors affecting length of gastation and birth weight of Nili-Ravi buffaloes. Animal Reproduction Science 14, 195-203.
Verma K and Yadav M C 1989 Genetic studies on dry period in Nili-Ravi buffaloes. Indian Journal of Dairy Science 42, 627-629.
Received 3 November 2014; Accepted 18 February 2015; Published 3 March 2015
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