Evidence map›Paper›PMID 33216226›Full record

ArticleTropical animal health and production2020

Genetic parameter estimates for milkability traits and their relationship with somatic cell score in South African Holstein cattle.

T S Tshilate, E Bhebhe, B Dube, C Rhode, N O Mapholi, O Matika, C B Banga

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Article in Tropical animal health and production, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

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2 citing papers in PubMed.

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5 · Who and what money

Authors and funding

7 authors.

T S TshilateDepartment of Animal Science, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa. tshilates@gmail.com.ORCID https://orcid.org/0000-0002-8248-8921
E BhebheDepartment of Animal Science, University of Venda, Private Bag X5050, Thohoyandou, 0950, South Africa.
B DubeAgricultural Research Council-Animal Production, Private Bag X2, Centurion, 0062, South Africa.
C RhodeDepartment of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa.
N O MapholiDepartment of Life and Consumer Sciences, University of South Africa, Private Bag X6, Florida, 1710, South Africa.
O MatikaCentre for Tropical Livestock Genetics and Health (CTLGH), Roslin Institute, University of Edinburgh, Easter Bush Campus, EH25 9RG, Edinburgh, United Kingdom.
C B BangaAgricultural Research Council-Animal Production, Private Bag X2, Centurion, 0062, South Africa.

Funding

Agricultural Research Council P02000078University of Venda SARDF/16/ANS/04
6 · The paper itself

Abstract

Milkability is an important functional trait, which is directly related to milking costs and udder health. There are no milkability traits incorporated in the South African dairy cattle breeding objectives and genetic parameter estimates for these traits are not available in this population. The main objective of the study was, therefore, to estimate the genetic parameters for milkability traits and its correlation with somatic cell scores in South African Holstein cattle. Data consisted of production and milkability records of 2719 Holstein cows, from ten herds, collected from 2016 to 2018. Genetic parameters were estimated by a multi-trait animal model using the restricted maximum likelihood (REML) procedure. Means for milking time (MT), average milk flow (AMF), maximum milk flow (MMF), and somatic cell score (SCS) were 5.20 min, 1.91 kg/min, 2.99 kg/min, and 2.06, respectively. The heritability estimates were low to moderate from 0.19 ± 0.07, 0.24 ± 0.06, 0.36 ± 0.11, and 0.41 ± 0.12, respectively, for SCS, AMF, MT, and MMF. The genetic correlations were significant (P < 0.05) among the three milkability traits ranged from - 0.31 ± 0.05 between AMF and MT to 0.85 ± 0.02 between AMF and MMF. Positive genetic correlations were observed between AMF and MMF, while the correlations for MT with the remaining milkability traits were negative. Genetic correlations of SCS with AMF, MMF, and MT were - 0.13 ± 0.04, 0.13 ± 0.04, and - 0.25 ± 0.12, respectively. The mean estimated breeding value (EBV) was estimated using cattle birth dates, and there was an increase in AMF of 0.0001 kg/min EBV per year on cattle born during the period 2002 to 2014. Maximum milk flow also showed an increasing genetic trend of 0.0003 kg/min per year over the same period. On the other hand, the genetic trend for MT was undesirable, as it increased by 0.0003 kg/min per year. The moderate to high heritability estimates for milkability traits showed that selection for improvement was possible in South African Holstein cattle. High genetic correlation between AMF and MMF implied that these two may be regarded as the same trait. Milking time can contribute towards improving the accuracy of estimating EBVs for SCS in a multi-trait analysis, and vice versa, due to the moderate correlation between the two traits. The marginal genetic trend in milkability traits may be an interrelated response to selection of other traits already under selection in the population such as SCS. Results of the current study provided a basis for including milkability traits of South African Holstein cattle in the breeding objectives.

Indexed as

AnimalsBreedingCattleCell CountFemaleLactationMilkPhenotypeSouth AfricaAverage milk flowGenetic parametersGenetic trendsMaximum milk flowMilking time

Identifiers

PMID33216226

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