Proceedings, Western Section, American Society of Animal Science.

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Proceedings, Western Section, American Society of Animal Science.

  1. 1. Proceedings, Western Section, American Society of Animal Science. Vol. 53, 2002. ESTIMATES OF GENETIC AND REPRODUCTIVE PARAMETERS IN A HOLSTEIN DAIRY HERD IN THE DESERTIC REGION AT THE NORTHWESTERN OF MEXICO. A.P. Marquez1, A.A. Quintana1, J. Rodríguez 1, J.F. Ponce O. S. Cobos 1, M. Montaño 1, H.G. Gonzalez2 and J.N. Guerrero 3 Universidad Autónoma de Baja California, Mexicali, Mexico1 Universidad Autónoma de Ciudad Juarez2 University of California, Agricultural and Natural Resources, Holtville. 3 ABSTRACT, 398 first lactation records for milk yield of groups and the evaluation be the sum of the estimate of the Holstein cows, daughters of 51 Holstein sires were group and the selection type evaluation of the deviation of analyzed by using least squares. The objective was to the individual sire from this mean. Data used in sire estimate genetic parameters and breeding values. The evaluation research and application, are field collected from environmental correlation (c2=.02) was used to estimate herds in which culling and selection have been practiced. breeding values. Cows were classified in three groups The objective was to estimate genetic parameters and according to the season of parturition. The model included: breeding values for milk yield in a Holstein dairy herd cow, age of dam, and season of parturition as fixed effects: located at north west of México. sire, sire x season of parturition interaction and the residual as random components. The average milk yield 305 d 2x in Materials and Methods first lactation cows was 8, 725.75 ±1,401.89 kg. The projected milk production to mature equivalent ME was 11, Data came from a dairy herd of Holstein cows, located in 012.20± 1,735.62 kg. Open days and services per Mexicali, Baja California, México, close to the international conception were: 148± 103, and 2.84± 2.09 respectively. border to Calexico, California. 398 first lactation records The averages for milk yield by season were: for milk yield of Holstein cows, daughters of 51 Holstein 9,028±1,294.34, 8,232.90±1,163.96 and 8,873±1,602.42 kg sires were analyzed by using least squares. Cows were to October-January, February-May and June to September , classified in three groups according to the season of respectively. A significant difference (P< 0.01) in milk parturition (October to January, February to May, and June yield was found in cows which parturitions occurred among to September). Data was analyzed by SAS Version 6.07 October to January than cows which parturitions occurred (SAS, 1992 ) The model included: cow, age of dam, and into February to May, but no significant differences (P> season of parturition as fixed effects: sire, sire x season of 0.05) were detected for cows which parturitions occurred parturition interaction and the residual as random among June to September. The variance components for components. milk yield due to sire (209,865.28) was highly significant (P<0.01). The estimated value of heritability for milk yield Genetic parameters was (h2= 0.33±0.37). The average predicted milk difference was 65± 113 kg. These estimates were different to the Variance components were obtained for milk yield, by reported values into sires summaries. The phenotypic hierarchization of lactations, nested within sires, to estimate correlation between 305 d milk in first lactation cows and the heritability (h2) value for milk yield through the intra projected milk difference was (rP=0.93). class correlation among half paternal sibs. The standard error of heritability (h2) was estimated by using the equation Key words: Heritability, Breeding values, first lactation by (Baker ,1964). Introduction e.e. (h2)= [ 2(n-1) (1-t) 2( 1-ki-1) ] 1/2 ki2 (n-s) (s-1) Sire evaluation can be structured as a process of prediction of future progeny of a sire produced by mating with where: t = σ2s specified females and making their records in some σ s + σ2w 2 specified environment (Henderson, 1972). Sewall Wright e.e.= standard error (1931) cited by Henderson (1972), suggested three types of s= sire prediction that might be of interest: (1) progeny of a h2= heritability particular mating, (2) future daughters in the same herd ki= number of individuals in each subclass without include a new sample of dams, (3) daughters out of t= intra class correlation a random sample of dams of the breed. Henderson, (1966) σ2 s = variance due to sire suggested that to account for genetic trend and for different σ2w= variance due to error selection polices of AI studs and dairymen ´s choice of sires Breeding values for natural service, bulls to be evaluated be divided into
  2. 2. Breeding values estimates of sires for milk yield were time. It suggest to be cautious to make predictions of the developed as follow: 1.Estimates of the average milk genetic potential of sires. The selection to other traits, the production of daughters of each sire, records were arbitrary genetic groups, the preferential treatment to some standardized to 305- day, two milking (2X), and mature cows, and the techniques of measurement, still being a equivalent (ME). Each record was corrected by year and probable cause of reduction in accuracy of the genetic merit season of parturition. The record of each cow was due to sire (Weigel et al., 1996; Wilder, 1988; Powell et al., expressed as deviation of the corrected average of their herd 1964, and Samuelson, 1995). mates, and breed average. 2. Weighting factors (ß) were estimated for each sire, by using: the milk yield of their Weigel et al., (1986) outstanding that the extensive daughters and compared to herd mates average, the international interchange of cattle, semen, and embryos heritability value (h2=0.36±.03) estimated in this study, the during the last twenty five years, conducted to the number of daughters by sire, and the environmental development of more accuracy methods to compare the correlation among half paternal sibs (c2=0.02), suggested by genetic merit of sires. Pearson et al., (1994) outstanding the (Dimov, et al., 1995). existence of limitations due to instable of regression equations used in the prediction of the genetic merit of Results and Discussion sires. Additionally the genetic evaluations of sires and variance components residuals must be of populations Least squares means for milk yield 305-day (2x), mature previously selected (Powell, et al., 1994). equivalent (ME) in kg, and services per conception are presented in Table 1. As shown , milk yield 305-day (2X) Implications 8724.50 kg, could be considerate as a reasonable high, due the fact this yield correspond to first lactation cows. Milk Results of this study suggest a reasonable high milk yield in yield 8724.50 kg adjusted to 305-day and (2X) in the herd first lactation cows. Existing evidence suggesting that high under study was 16.67% higher if compared to the average production in first lactation is positively correlated to later milk yield 305-day (2X) 7270 kg obtaining in Holstein lactations. Most decisions on selecting sires must be made cows that have completed four lactations in United States on basis of performance in first lactation of the daughters. (USLGE, 1995). Sires can be ranked on the daughters, first records with little loss in accuracy. First record gives essentially as reliable an Table 1. also shown the projected milk yield to ME. The estimate of a cows, breeding value measured by the value of this estimates 11, 012.28 kg. Henderson et al ., daughters performance, as does an appropriately weighted (1964), analyzed hundreds of thousands of records of combination of multiple records. complete first lactations Holstein cows. The authors estimates a correlation (r=0.80) between milk yield based in complete first lactations records and the prediction to (M E). The estimates of correlation (rp=0.93) based in a limited number of observations between milk yield based in Literature Cited complete first lactations records and the prediction to (ME); the predictive capacity of the used model was (r2=0.86). Dimov, G., L. G. Albuquerque, J. F. Keown, L. D., Van Analysis of Variance Components for milk yield are Vleck and H. D. Norman. 1995. presented in Table 2. As shown the effects of sires resulted highly significant (P<.01) for milk yield. The estimates of Variance of interactin effects of sire and herd for yield traits heritability (h2= 0.36 ±.03) for milk yield in this study was of Holsteins in California, New Cork, and Pennsilvania calculated of the estimates of Variance Components (Table with an Animal Model. J. Dairy Sci. 78:939. 2) through the intra class correlation among half paternal sibs, as four times the variance due sires dived by the total García, E., 1973. Modificaciones al sistema de clasificación phenotypic variance. The estimates of heritability climática de Köpen. Instituto de Geografía, UNAM, (h2=0.36±.03) for milk yield in this study is quite similar to D.F. México. the values (h2=0.29, h2=0.44, h2=0.33 and h2=0.36) estimated for this trait by Hudson et al., 1981; Miztal et al., Henderson, C. R. 1972. Sire evaluation and genetic trends. 1992, and Dimov et al. , 1995), respectively. Proceedings of the Animal Breeding and Genetic Symposium in Honor of Dr. Jay L. Lush. Virginia Breeding values Polytechnic Institute and State University Blacksburg, Virginia. American Society of Animal Science, The estimates of breeding values expressed as the Predicted American Dairy Science Association. Difference for milk yield in this study are different to the reported values of Predicted Difference for this trait into Henderson, C.R and L.D., Van Vleck. 1964. Improvement sire summaries. The genetic potential of a sire is relative in production of New York Holsteins due to artificial and the validity of the estimates must be function of the insemination. J. Dairy Sci. 44: 1328. population where it was estimated. However the publications of sire summaries shown variations through
  3. 3. Henderson, C. R. 1966. A sire evaluation method which accounts for unknown genetic and environmental Samuelson, D. J., Pearson, R. E. 1995. Accuracy of trends, herd differences, season, age effects, predicting genetic merit from pedigree information for differential culling. Proc of Symp. on Estimating bulls entering stud samoling programs. J. Dairy Sci. 78: breeding values of Dairy Sires and Cows. Washington, 2057. D. C. Thatcher, W. W., R. L. Badinga, R. L. Collier, H. H. Head, Hudson, G.F. S. and L.D. Van Vleck. 1981. Relationship and C. J. Wilcox. 1984. Thermal stress effects on the between production and stayability in Holstein cattle. J. bovine conceptus: early and late pregnancy. Dairy Sci. 64:2246. Reproduction of ruminants in zone tropicale. Inst. Natl. Res. Agron Publ (Abstr.). Miztal, I. T., Lawlor, T., Short, and M. Van Raden. 1992. Multiple trait estimation of variance components of U.S. Livestock Genetics Export Inc. 1995. La unica fuente yield and type traits using an Animal Model. J. Dairy genética lechera de calidad superior. Bull No. 12. St. Sci. 75:544. Louis Mo. Powell, R. L., Norman H. D. 1984. Research needs in cow Weigel, K. A. 1996. Impact of second country data of evaluation. National Invitational Workshop on Genetic foreign bulls on international evaluations of dairy bulls. Improvement of Dairy Cattle Milwaukee Wis. USA. J. Dairy Sci. 77:900. Powell, R. L., Wiggans, G. R., and P.M. Van Raden. 1994. Weilder, J. S., Van Vleck, L. D. 1988. Relative economic Factors affecting calculation and use of conversion values assigned to milk, fat Test, and type in pricing of equations for genetic merit of dairy bulls. J. Dairy Sci. bull semen. J. Dairy Sci. 71: 492. 77:2679. Table 1. Least squares means for milk yield 305-day (2X) , mature equivalent, and services per conception of first lactation Holstein heifers mated AI to Holstein sires. Trait Mean values SD Milk yield/cow 305-day (2x) kg 8724.50 kg 1,401.89 Milk yield Mature Equivalent 11,012.28 kg 1,735.62 Services per conception 2.84 2.09 SD= Standard deviations. Table 2.Variance components for milk yield of first lactation Holstein cows mated to Holstein sires. Source Mean Squares (P > F) Sire 2050826.65 .0003 Season of parturition 18935787.15 .0001 Residual 1637826.60

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