Genetic Selection for Health Traits Using Producer-Recorded Data. II. Genetic Correlations, Disease Probabilities, and Relationships with Existing Traits

Abstract

The objectives of this study were to calculate genetic correlations between health traits that were recorded in on-farm herd management software programs and to assess relationships between these traits and other traits that are routinely evaluated in US dairy sires. Data consisted of 272,576 lactation incidence records for displaced abomasum (DA), ketosis (KET), mastitis (MAST), lameness (LAME), cystic ovaries (CYST), and metritis (MET) from 161,622 cows in 646 herds. These data were collected between January 1, 2001 and December 31, 2003 in herds using the Dairy Comp 305, DHI-Plus, or PCDART herd management software programs. Binary incidence data for all disorders were analyzed simultaneously using a multiple-trait threshold sire model that included random sire and herd-year-season of calving effects. Although data from multiple lactations were available for some animals, our genetic analysis included only first parity records due to concerns about selection bias and improper modeling of the covariance structure. Heritability estimates for the presence or absence of each disorder during first lactation were 0.14 for DA, 0.06 for KET, 0.09 for MAST, 0.03 for LAME, 0.04 for CYST, and 0.06 for MET. Estimated genetic correlations were 0.45 between DA and KET, 0.42 between KET and CYST, 0.20 between MAST and LAME, 0.19 between KET and LAME, 0.17 between DA and CYST, 0.17 between KET and LAME, 0.17 between KET and MET, and 0.16 between LAME and CYST. All other correlations were negligible. Correlations between predicted transmitting abilities for the aforementioned health traits and existing production, type, and fitness traits were low, though it must be noted that these estimates may have been biased by low reliability of the health trait evaluations. Based on results of this study, it appears that genetic selection for health disorders recorded in on-farm software programs can be effective. These traits can be incorporated into selection indices directly, or they can be combined into composite traits, such as "reproductive disorders", "metabolic disorders", or "early lactation disorders".

Genetic parameters for producer-recorded health data in Canadian Holstein cattle

“…Zwald et al (2004b) found a similar result. Cows with KET have a high probability of getting LDA (Stengä rde and Pehrson, 2002); therefore, the phenotypic correlation should also be high.…”

“…Therefore, the accuracy of diagnosis is higher than for other traits. Heritability for COD (0.05) was consistent with results based on veterinarian reports (Distl et al, 1991;Mä ntysaari et al, 1993) and more recent estimates with threshold models (Hooijer et al, 2001;Zwald et al, 2004a and2004b;Heringstad, 2010;Koeck et al, 2010). The low heritability for COD seems to be caused by the large influence of the producer on the observation of the trait.…”

“…Heritability of LAME was very low (0.04), but was comparable with other results from the threshold model (Zwald et al, 2004a and2004b). The phenotypic variance of this trait was also lower than that for the other two traits evaluated with single-trait models.…”

“…Some health data analyses have already applied threshold model methodology (e.g. Uribe et al, 1995;Zwald et al, 2004a and2004b;Heringstad, 2010;Koeck et al, 2010) whereas a linear model approach (although not optimal) is also used.…”

Produção de leite de vacas da raça Holandesa de pequeno, médio e grande porte

“…(DONKER et al, 1983), (DICKINSON et al, 1969;LAMB et al, 1977;YEREX et al, 1988), além de apresentarem maior vida útil e menos problemas sanitários. Dessa forma, a estratégia de elevar a produção de leite e o tamanho dos animais é inadequada, considerando sua associação com problemas reprodutivos e problemas de saúde (MAHONEY et al, 1986: ZWALD et al, 2004, com destaque para mastite (HERINGSTAD et al, 2003). Esses problemas têm crescido também no rebanho brasileiro (MADALENA, 2008), especialmente em vacas da raça Holandesa (WOLFF et al, 2004).…”