Breeding Program of the Bulgarian Murrah Buffalo

Transcription

1 Breeding Program of the Bulgarian Murrah Buffalo Tzonka PEEVA *, Plamen NIKOLOV, Tania NIKOLOVA, Pencho PENCHEV and Yordanka ILIEVA Bulgarian National Association for Development of Buffalo Breeding, 3 Simeon Veliki Blvd., Shumen 9700, Bulgaria *Corresponding tzonkapeeva@abv.bg ABSTRACT The aim of Bulgarian National Association for Development of Buffalo Breeding (BNADBB) is to work out an effective breeding scheme (BS) for fast genetic progress and improved profitability of production for Bulgarian Murrah (BM) buffalo through application of the latest achievements at the field of breeding and use of modern selections methods. Basic principles for the development of the breeding program is based on the most important phenotypic and genotypic parameters of the selection traits; fixed factors of the breeding policy, selection intensity (I), duration of the generation interval (L), breeding value (BV), optimization of selection by selection index (SI) including age at first calving (AFC), calving interval (CI) and milk yield for first lactation (MYFL); estimation of genetic progress (ΔG). Keywords: AFC, breeding value, Bulgarian Murrah buffalo, genetic gain, MYFL, selection index INTRODUCTION The main objective of the Breeding ptogram of the Bulgarian Murrah (BM) breed, created on the basis of crossing between the native Bulgarian buffalo and the Murrah breed from India, is to work out an effective breeding scheme (BS) for fast genetic gain and improved profitability of the farms through application of modern methods of selection. Selection in buffalobreeding is a more difficult and complex process in comparison with cattle, resulting from the differences between the species. The difficulty of applying these methods of selection originate from the fact that it is to be applied in smallholders in the private sector. The realized genetic progress is lower than the theoretic one because of the various factors reducing the efficiency of theoretical models. These limitations are much more present in buffaloes. Independently of this difficulty our efforts should be directed towards more effective methods of selection and breeding systems to increase the genetic progress in the buffalo population. KEY STEPS IN THE BREEDING PROGRAM Number of buffaloes According to "Agrostatistics" program of the Ministry of Agriculture (2012) dated , the number of buffaloes was 9,900, of which 6,300 dairy Accepted April 10, 2013; Online November 11,

2 buffaloes (Table 1). Compared to the same time in 2010 it increased by 7.6 and 11.7 % for total number and dairy buffaloes, respectivly. Roughly 70% of the total number of buffaloes are reared in herds with more than 20 heads. The average size of the herds is 12.8 heads. The smallest buffalo population in Bulgaria was registered in Genetic Progress ( G) The value of the realized genetic progress determines the selection effectiency in the Bulgarian Murrah breed. Despite of the high phenotypic performance of the trait, in practice it is possible to have a negative progress. This is due to ill-organized selection and inaccurate methods of genotype evaluation. According to Alexiev (1979), Vankov (1980) and Peeva (2000), the predicted genetic progress of milk yield is from to 3.2%. Breeding value Breeding value on the basis of the pedigree. Selection based on pedigree is the earliest evaluation of animals. Selection can be based either on the information about one parent or on the basis of information about the two parents, or the grandparents. In buffalo farms this kind of selection is used very often. Selection of bulls based on their mothers is less effective. Relatively high genetic progress ( G= 1.78%) can be attained when the selection of bulls is based on their fathers. Breeding value on the basis of the phenotypic performance of the selection trait. This selection is too much time consuming. The animal recording is the most important task of the breeding work in the Assotiation. The selection of the buffaloes was done on the basis of the information from milk recording. The application of AI with frozen semen is highly recommended for the genetic improvement of the buffaloes. About 70% of the buffalo cows are under milk recording (A4). Breeding value on the basis of half and full sibs. The coefficients of determination (R²) show that only 6.42 and 7.63% of the expected genotype is formed by the productivity of the half and full sister and and 92.37% by other factors. The analysis of the many our researches shows that the relative accuracy of the selection by using the information from the lateral relatives would not have a significant effect on the magnitude of the genetic progress in the population. Despite of the low accuracy of the method, it allows early prediction of breeding value of the bulls. Proreny testing. Progeny testing has been proposed persistently in the recent three decades as a method to accurately estimate breeding. Progeny testing consists in taking into consideration the performance of the offspring as a criterion for selection among the parents. The principles of the progeny testing come from the sampling nature of inheritance. Sire index is used in the selection of best sires among those subject to testing. In Bulgaria the most commonly used was the daughter-dam comparison representing the difference between the production levels of a sire s offspring and their dams. Another method of evaluating sires is the daughter-herdmate comparison practised in Bulgaria as well. The implementation of AI in buffaloes significantly increased the bulls influence on the creation of the dairy population. This estimation was and remains a basic method of evaluation of the additive genotype. The large size of the farms ( buffalo cows) allowed to accomplish the progeny testing of the bulls. The milk 237

3 recording (A4) and the well organized information system in the Bulgarian National Association for Development of Buffalo Breeding are the basis for realizing the progeny testing program. Over 20 recorded daughters per sire were used in order to increase the accuracy of progeny testing. SELECTION METHODS USED IN THE BREEDING PROGRAMME Selection index The method of selection indices, as more effective than the tandem selection and independent culling levels, has been applied during the last decades in the countries with developed cattle breeding. Most of the theories of the quantitative genetics and the selection criteria are based on the individual s phenotype, but a problem appears in their practical application for simultaneous improvement of a couple of traits. In buffaloes the method of selection index is introduced 20 years ago. Some authors (Gajbhiye, 1987; Sharma & Singh, 1988; Gajbhiye & Tripathi, 1991) reported significant effect of multiple selection. For first time in Bulgaria the method of selection indices was used by Peeva (2000) in buffalo breeding. The selection index was expressed by the following equation: I = b 1 P 1 + b 2 P 2 + b n P n = Σb n P n, where: P 1 phenotypic value of the economic traits, included in the index (P = 1...n) b 1 regression coefficient (b = 1...n) Selection indices have been developed combining the traits: milk yield at first lactation (MYFL), fat (F), protein (P), body weight of the buffalo cows (BW), age at first calving (AFC) and calving interval (CI) as most important for the selection in Bulgarian buffalo population. Fifty-seven selection indices are constructed with different combination of the traits. Their relative effectiveness depends on the number of the included selection traits. The index combining milk yield for 305-day first lactation, calving interval, and age at first calving: I = MYFL + (-4.81 CI) + ( AFC) proves to be most efficient. If the selection uses this selection index, the genetic merit for MYFL, CI and AFC will be 36.8 kg, days, and days, respectively. Identification and recording The main objectives of identification and recording are: - identification of high productive animals; - optimization of nutrition and management; - estimation of Breeding Value; - optimization of the genetic progress. The well-organized buffalo farms created good conditions for milk recording, which comprised all buffalo cows on the large farms. Another reason for establishing a well-organized recording system was the implementation of machine milking on buffalo farms and AI. 238

4 Body weight of young animals is: - at 6 months of age 140 kg - at 12 months of age 290 kg - at 22 months of age 400 kg Body weight of breeding animals is given in Table 2. Body measuremens taken at 3, 6, 12, 18, and 24 months Age and body weight at first insemination are: -body weight kg -age months Selection criteria for bull-mothers Average values of the milk production: І- lactation ІІ- lactation ІІІ- lactation Milk yield, min, kg % fat, minimum % protein, minimum Body measurements and body weight height at withers 140 cm body length 146 cm rump width 58 cm chest girth 220 cm body weight kg Type rating In all countries with traditions in buffalo breeding no proper attention is paid to this type of selection, as to the selection on productive and reproductive traits. Only in the recent decades does it attain definite importance. Depending on breed, type of productivity, and region of breeding, clearly are outlined the features of the buffalo that form the ratings of the different traits to determine the overall score. Studies of Bulgarian (Peeva, 1981, Peeva & Alexandrov, 1993) and other authors (Velea, 1991, Velea et al., 1991, Bingzhuang et al., 2002) show that body measures, type and conformation are more substantially affected by the environmental than by the additively determined factors. On the basis of the relationships between the body measures and the milk production traits Peeva (1981) and Saini and Gill (1984) have, independently for Bulgaria and India, developed 100-score cards involving four main groups of traits. Hundred-score cards were used for estimation including four groups of traits general appearance (30 scores), dairy character (20 scores), body capacity (20 scores), mammary system (30 scores) and overall rating in Breeding Programme (Peeva, 1981). OPTIMIZATION OF THE BREEDING PROGRAMME The optimization of the breeding program is based on the most important phenotypic and genetic parameters of productive and reproductive traits (Penchev, 239

5 1999; Peeva, 2000; Ilieva, 2006) (Table 3) and fixed factors of the breeding policy (Table 4). The phenotypic parameters of the selection traits, including in Breeding Programme were determined by LS-analysis as follow: Y ijmnp = μ + a i + b j + l m + f n + g p + E ijmnp Where: Y ijmnp observation vector μ - overall mean a i fixed effect of i -th farm in j th season, from m -th line, on n -th lactation, during p th period (i= ) b j fixed effect of j th season in i -th farm from m -th line, on n -th lactation, during p th period (j= 1...4) l m fixed effect of m -th line in i -th farm during j th season for n -th lactation, during p th period (m= 1...6) f n fixed effect of n -th lactation in i -th farm during j th season for m -th line during p th period (f = 1 3) g p fixed effect of p th period в i -th farm during j th season for m -th line of n -th lactation (р= 1...4) E ijmnp residual error Based on the optimization and reporting the impact of various factors on the genetic progress for milk yield, age at first calving and calving interval as optimal, the following criteria and parameters were suggested: Sires per stud for AI 3 Preliminary selected bull mothers 135 Actually selected bull mothers 45 Young tested bulls 15 Tested sires 11 Number of stored doses from a tested sire Number of daughters per bull 15 REFERENCES Alexiev, A A breeding program for improvement of the native Bulgarian buffalo on dairy direction. Thesis, Sofia. Bingrhnang, Y., L. Zhongquan, Z. Guiwen, Z. Qingkun and Q. Jing Present status of cross improvement and utilization of Guanidxi buffalo and proposal for near future. In: Proceedings of the First Buffalo Symposium of America, 1-4 September 2002, Belem, Brazil. pp Gajbhiye, P.U Envolving restricted indices for selection in buffaloes. Ph.D. Thesis. Kurukshetra University, India. Gajbhiy, E.P.U. and N. Tripathi Multiple traits selection for the genetic improvement of Murrah buffaloes. In: Proceedings of the Third World Buffalo Congress, May, Varna, Bulgaria. Vol. 1: 47. Ilieva,Y Optimization of productive life in buffalo cows of the Bulgarian Murrah Breed. Ph.D. Thesis, Sofia. Ministry of Agriculture and Food Agrostatistics. Bulletin

6 Peeva, T.Z Study on type and body-build of the buffalo population raised in Bulgaria. Ph. D. Thesis, Sofia. Peeva T.Z., A. Alexandrov Comparative evaluation of type and build of buffalo cows. Zhivotnovadni Nauki, 30: Peeva, T.Z Optimized selection methods in buffaloes. Dr.Sci. Thesis, Sofia. Penchev, P A study on the phenotypic and genotypic parameters of selection traits in the newly created buffalo population in Bulgaria. Ph.D Thesis, Sofia. Saini A. and R.S. Gill Physical factors affecting scorecard judging and its relationship with yield in buffaloes. In: 7th Workshop of all India Coordinated Research Project on Buffalo Breeding. PAU, Ludhiana, India. pp Sharma, R.C. And B.P. Singh Genetic studies on Murrah buffaloes in livestock farms in Uttar Pradesh. In: Proceedings II -nd World Buffalo Congress December, New Delhi, India. Vol. 2: Vankov, K Establishing phenotypic and genotypic parameters of the selection traits in buffaloes in Bulgaria. D.Sci.Thesis, Sofia. Velea, C The Roumanian breed of buffalo. In: Proceedings of the Third World Buffalo Congress May, 1991, Varna, Bulgaria. 2: Valea, C., I. Bud, Gh. Muressan, V. David, M. Vomir, C. Cristea and L. Lisei The main milk traits of Romanian buffaloes breed. In: Proceedings of the Third World Buffalo Congress May, 1991, Varna, Bulgaria. 2: Table1. Number of buffaloes according to Agrostatistics, Ministry of Agriculture, Years :2010 Total % Buffalo cows % Table 2. Body weight of breeding animals. Age, mo Male Female Body weight kg Daily gain g Body weight kg Daily gain g

7 Table 3. Phenotypic and genetic parameters of the selection traits. Traits Values of parameters day milk yield at 1-st lactation, kg Fat content in milk,% Average number of lactations 4 4. Maximum number of lactations Calving interval, days Inseminations per conception Daily gain of female calves from birth to weaning, kg/day Daily gain of female calves from 6 months to conception, kg/day Daily gain of young bulls, kg/day Age at first calvind, days Proportion of live borne calves of the total number of borne calves Proportion of calves at 6 mo of the total number of borne calves Proportion of calved heifers of the number of female calves at 6 mo, % Proportion of culled calves of the total number of borne calves, % Phenotypic standart deviation for lactation milk yield, kg Heritability of milk yield Heritability of age at first calving Heritability of calving interval Heritability of daily gain Repeatability of milk yield Selection intensity in bull dams Selection intensity in buffalo cows Selection intensity in sires of bulls Phenotypic standart deviation for daily gain (SD), g Numbers of buffalo cows for 1 effective daughter Stored semen doses per year per bull Generation interval in sires of bulls, years Generation interval in dams of bulls, years Live weight of young breeding bulls, kg Live weight of mature bulls, kg

8 Table 4. Fixed factors of the breeding policy. Factors Value 1. Total number of buffaloes (year 2011) Size of active breeding population, heads Number of potential bull mothers Bull mothers per 1 selected young bull 4 5. Proportion of culled bulls after semen production Proportion of culled bulls after sexual activity Proportion of heifers at first calving Sires per stud for AI 3 9. Storing period of frozen semen, years