Proceedings, Western Section, American Society of Animal Science.
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.
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
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
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
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
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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