Paratuberculosis sero-status and milk production, SCC and calving interval in Irish dairy herds

Genetic parameters were estimated for antibody response to paratuberculosis (Mycobacterium avium ssp. paratuberculosis) using milk ELISA test results, collected and analyzed by National Milk Records, from Holstein Friesian cows on UK dairy farms in their first 3 lactations. Milk ELISA test results were obtained from 2007 to 2012 and combined with milk recording data and pedigree information. The reduced data set edited for the purposes of genetic parameter estimation consisted of 148,054 milk ELISA records from 64,645 lactations in 40,142 cows of 908 sires, recorded in 641 herds. Milk ELISA test results were log-transformed and univariate analysis of 3 alternative animal models and equivalent sire models were considered. The most appropriate model included additive genetic and permanent environmental random effects, whereas maternal effects were significant according to likelihood ratio test and Akaike's information criterion but not for Bayesian information criterion. Heritability and repeatability estimates were 0.06 and 0.37, respectively, for the chosen animal model and its equivalent sire model. A subset of the data including herds with greater than 10% positive tests gave a slightly higher heritability of 0.08. Favorable but generally low significant genetic correlations were obtained between antibody response with 305-d milk yield (-0.16), 305-d protein yield (-0.16), log-transformed lactation-average somatic cell count (0.15), and the number of mastitis episodes (0.22). Thus, selection on the antibody response to paratuberculosis, should not be detrimental to production or udder health traits. Testing cattle for paratuberculosis is important for its use in control programs and although the heritability of antibody response was low, breeding against the disease might be a good prospect as a preventative measure to assist together with other approaches in an overall control strategy.

Section: Productionmentioning

confidence: 56%

The genetics of antibody response to paratuberculosis in dairy cattle

Pritchard

Mrode

Coffey

et al. 2017

“…These results suggest the existence of differences in the performance of Portuguese POS and NEG farms independent from MAP status. A higher EBV for milk yield has already been reported for MAP-positive herds in Ireland (Hoogendam et al, 2009), but no significant effect of MAP status at animal, lactation, or herd level on milk yield or lnSCC was found. That might be because only one lactation per cow was evaluated and irrespective of parity number.…”

Section: Milk Productionmentioning

confidence: 71%

Association of paratuberculosis sero-status with milk production and somatic cell counts across 5 lactations, using multilevel mixed models, in dairy cows

Martins

Oliveira

et al. 2018

The aim of this work was to investigate associations between individual cow Mycobacterium avium ssp. paratuberculosis (MAP) seropositivity, 305-d corrected milk production, and somatic cell count during 5 lactations lifespan in Portuguese dairy herds using multilevel mixed models. We used MAP serum ELISA (Idexx MAP Ac, Idexx Laboratories Inc., Westbrook, ME) results (n = 23,960) from all the 20,221 adult cows present in 329 farms and corresponding 47,586 lactation records from the National Dairy Improvement Association. Cows and farms were classified as positive or negative. Multilevel mixed models were used to investigate the association of cow MAP status with variation in milk production and somatic cell count. Cow MAP status, farm status, and lactation number were considered as independent variables. A quadratic function of lactation number was used to mimic the effect of lactation order on milk production. The models considered 3 levels: measurement occasion (level 1) within cow (level 2) and cow within farm (level 3). Four final models were produced, including all herds and cows, to address the effect of farm status (models 1 and 2) or the effect of cow status (models 3 and 4) on the outcome variables. Our results show that MAP status affects milk production. Losses are detectable from third lactation onward. During the first 5 lactations, positive cows accumulated an average loss of 1,284.8 kg of milk when compared with the negative cows. We also observed that somatic cell counts were higher in positive cows and a positive interaction occurs between cow status and lactation number, suggesting a positive association between MAP infection and increased somatic cell counts. Our results are in line with previous studies, suggesting a possible positive relation between cow milk production and susceptibility to MAP infection.

“…During the second phase of eligibility screening, 4 studies were excluded because the data had been published in a subsequent study (Kudahl et al, 2003;Lombard et al, 2005b;Sorge et al, 2007;VanLeeuwen et al, 2002). Fifteen studies were excluded because the required level of detail was not reported regarding the estimate and error term (Whitlock et al, 1985;Wilson et al, 1993;Chaffer et al, 2002;Hoogendam et al, 2009;Sibley et al, 2012), the outcome was not comparable (DeLisle and Milestone, 1989;Nielsen et al, 2009), they did not (or did not appear to) account for herd as a possible confounder (Collins, 1991;Sweeney et al, 1994;Raizman et al, 2007Raizman et al, , 2009Pantoja et al, 2010), parity or age did not appear to be accounted for in the analysis (Rad et al, 2010), or the comparisons were between different lactations within the same animal (Benedictus et al, 1986(Benedictus et al, , 1987. Two studies were unavailable (Dinsmore, 1986;Pavlík et al, 1994).…”

Section: Study Selection: Phasementioning

confidence: 99%

The effect of paratuberculosis on milk yield—A systematic review and meta-analysis

McAloon

Whyte

et al. 2016

Bovine paratuberculosis is a disease characterized by chronic granulomatous enteritis causing protein-losing enteropathy. Adverse effects on animal productivity are key drivers in the attempt to control paratuberculosis at the farm level. Economic models require an accurate estimation of the production effects associated with paratuberculosis. The aim of this study was to conduct a systematic review and meta-analysis to investigate the effect of paratuberculosis on milk production. A total of 20 effect estimates from 15 studies were included in the final meta-analysis. Substantial between-study heterogeneity was observed. Subgroup analysis by case definition and study design was carried out to investigate heterogeneity. The majority of between-study variation was attributed to studies that defined cases on serology. Calculation of a pooled effect estimate was only appropriate for studies that defined cases by organism detection. A reduction in milk yield, corrected for lactation number and herd of origin of 1.87 kg/d, equivalent to 5.9% of yield, was associated with fecal culture or PCR positivity in individual cows.