52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Heritability estimates for milk and solid production in Holstein breed in Paraná State
Henrique Alberto Mulim1, Victor Breno Pedrosa2, Gabrieli de Souza Romano3, Adriana de Souza
Martins2, Pedro Guimarães Ribas Neto4, Silvano Francis Valoto4, Ana Priscila Doria5
1
Graduando em Zootecnia, Universidade Estadual de Ponta Grossa - Bolsista Fund. Araucária - Paraná. [email protected]
Departamento de Zootecnia da Universidade Estadual de Ponta Grossa - Paraná
3
Pós-Graduanda em Zootecnia, Universidade Federal da Bahia – Bolsista FAPESB - Bahia
4
Associação Paranaense do Criadores de Bovinos da Raça Holandesa – Paraná
5
Graduanda em Zootecnia, Universidade Estadual de Ponta Grossa - Paraná
2
Abstract: The objective of this study was to estimate the heritability for milk, fat and protein of 19,756 first
lactation Holstein cows, belonging to the database of the Paraná Association of Holstein Cattle Breeders.
Were estimated variance components and heritability by Restricted Maximum Likelihood (REML) method
using the VCE6.0 program, under animal model. The mean for milk, fat and protein production, in
kilograms, with standard deviation, respectively, were 8910.24 ± 1825.86; 292.91 ± 64.65; 273.85 ± 52.40. The
results of heritabilities were 0.21 ± 0.02; 0.26 ± 0.02 and 0.21 ± 0.018, respectively, for milk, fat and protein, in
kilograms. In front of the estimates, it is recommend the inclusion of the studied traits, as selection criteria in
breeding programs of Paraná state.
Keywords: dairy cattle, fat production, parameter genetic, protein production, variance components
Estimativas de herdabilidade para produção de leite e sólidos em animais da raça Holandesa no
estado do Paraná
Resumo: Objetivou-se com este estudo estimar as herdabilidades para produção de leite, gordura e proteína
de 19.756 vacas primíparas da raça Holandesa, pertencentes ao banco de dados da Associação Paranaense de
Criadores de Bovinos da Raça Holandesa. Foram estimados os componentes de variância e herdabilidade
através do método de Máxima Verossimilhança Restrita (REML) utilizando-se o programa VCE6.0, sob
modelo animal. As médias para produção de leite, gordura e proteína, em quilos, com seus respectivos
desvios padrões foram 8910.24 ± 1825.86; 292.91 ± 64.65; 273.85 ± 52.40. Os resultados das herdabilidades
foram de 0.21 ± 0.02; 0.26 ± 0.02 e 0.21 ± 0.018, respectivamente para produção de leite, gordura e proteína, em
quilos. Diante das estimativas obtidas, recomenda-se a inclusão das características estudadas, como critério
de seleção, de programas de melhoramento genético do estado do Paraná.
Palavras–chave: bovinocultura de leite, componentes de variância, parâmetro genético, produção de
gordura, produção de proteína
Introduction
The Paraná state is nationally recognized as one of the most important producers of milk in Brazil.
The state herd is mostly characterized by Holstein cattle, which produces high milk yields and a large
quantity of solids in comparison to the rest of the country.
Milk production have been the principle criteria for cow culling and sire selection in Brazil. However,
the industry of dairy products have begun to pay premiums for solids production. Changes in pricing systems
have aroused interest in breeding dairy cattle for increase fat and protein yields, but less is known about the
genetics of fat and protein than milk. Thus, most producers are seeking for an evolution of these milk
components through selection methods, expecting to elevate the average production of their population.
Quantify how much of the production is due to genetics, supports the selection of superior animals and, as
consequence, improve the genetic merit of the herd (Abdullahpour et al., 2013).
Know the genetic parameters estimation are essential to conduct an efficient breeding program. For
example, heritability will measure the degree of similarity between the progenies performance compared to
parents performances. If this is high, it is expected that animals with high performance generate progenies
with high performance. If low, parents production will not represent much about the expression of the
offspring production. The aim of this study was to estimate the heritability of milk, fat and protein yields and
evaluate the advantages of include this traits in selection programs of Holstein cattle in Paraná state.
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Material e Methods
In this study were used data of 19,756 first lactation cows belonging to the database of Paraná State
Association of Holstein Cattle Breeders, born between 1990 to 2012 and with 26.84 months average of age
at first calving. The data files were processed at the Ponta Grossa State University, in the laboratory of study
on animal breeding - LeMA.
The traits evaluated, in kilograms, were milk production (MILK), fat production (FAT) and protein
production (PROT), adjusted for 305 days. The effects included in the model were the fixed effects of
contemporary group (CG), and the effect of calving age as covariate. Still, it was considered the genetic
additive and animal permanent environment as random effects. The CG was created considering the
interactions of herd-year-month effects and contemporary groups with less than three observations were
excluded from data file.
For the estimation of variance components was considered a multitrait model, in which all traits were
evaluated together. In matrix format, the model could be represented as follows,
y = Xb + Wp + Za + e
where: y = vector of traits; b = vector of solutions for the fixed effects; p = vector of solutions for the
random effect of permanent environment; a = vector of additive genetic solutions ; X, Z, W = incidence
matrix for fixed effects, additive genetic and permanent environment, respectively; e = vector of residues.
The components of (co)variance and heritability were estimated by REML, using VCE6.0 program
(GROENEVELD, 2008) in an animal model.
Results and Discussion
The table 1 presents the results of descriptive statistics of milk, fat and protein in kilograms, adjusted
for 305 days of lactation.
Table 1– Description of the data set structure, where N is the number of
animals, Mean is the average, S.D. is the standard deviation,
Min is the minimum and Max the maximum.
MILK (kg)
FAT (kg)
PROT (kg)
19756
19674
19526
N
8910.24
292.91
273.85
Mean
1825.86
64.65
52.40
S.D.
4502.00
151.00
151.00
Min
14957.00
599.00
531.00
Max
Lowest averages were found by Paula et al. (2008), 8181.23 ± 1903.51; 270.88 ± 67.58 and 249.01 ±
55.65, respectively for milk, fat and protein yields in a study conducted with the same breed, in the state of
Paraná. This fact may be related to a possible evolution of the production for Holstein cows in the mentioned
state. Similarly, lower values for milk production (7408.14 ± 1847.72) were obtained by Bignardi et al.
(2008) in a study conducted in the Southeastern states of Brazil. This result contributes to emphasize the
high average productivity of dairy cows in Paraná.
The estimates of variance for genetic, permanent environment, residual and phenotypic effects as
well, heritabilities are shown in Table 2.
Table 2 – Estimates of genetic variance (σ2g), permanent environmental variance (σ2pe), residual
variance (σ2e), phenotypic variance (σ2p) and heritability (h2), with their respective standard
errors, for milk, fat and protein yields.
Estimates
MILK
FAT
PROT
451623.85 ± 43496.28
669.86 ± 55.33
359.037 ± 33.386
σ2g
10430.55 ± 12541.67
17.028 ± 14.491
0.03274 ± 0.621
σ2pe
1647650.09 ± 39575.29
1932.96 ± 48.62
1379.72 ± 31.47
σ2e
2
2109704.486
2619.854
1738.787552
σp
0.21 ± 0.02
0.26 ± 0.02
0.21 ± 0.018
h2
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
The heritability found in this study were similar to those obtained by Paula et al. (2008), 0:27 ±
0.0003; 0.28 ± 0.0002; 0:27 ± 0.0002, respectively, for milk, fat and protein, utilizing Bayesian methodology
to calculate the estimates. Similar results were obtained by Zink et al. (2012), (0:20 ± 0:01; 0:23 ± 0:01) and
Abdullahpour et al. (2013) (12:22; 00:23), respectively, for milk and protein production, both for Holstein
cows. These results are consistent with the values obtained in national breed herds, indicating that the
studied population presents heritability coefficients that suggest the use of these traits as selection criteria.
Still, studies conducted in Canada by Loker et al. (2009) showed a higher heritability for milk
production (0.38) when compared to the results presented in this study. Heritability results for milk
production trait, from studies in Canada and the United States, generally have higher coefficients of
heritability, reflecting the long period of selection carried out in these countries.
Conclusions
The heritability estimates obtained for milk, fat and protein yields were moderate and can be
recommended as selection criteria in animal breeding programs implemented by the state of Paraná
producers.
Acknowledgements
We are greatful to Associação Paranaense dos Criadores de Bovinos da Raça Holandesa (APCBRH)
for supplying the data set.
Literature Cited
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de vacas da raça Holandesa – Revista Ciência Rural de Santa Maria 38:1705-1710
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