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Direct and indirect effects of Johne's disease on farm and animal productivity in an Irish dairy herd.

Richardson E, More S - Ir Vet J (2009)

Bottom Line: In contrast, little effect was noted for sub-clinical infections.These direct effects of JD infections, in combination with increased culling for infertility and increasing replacement rates, had a negative impact on farm production.Results from this study provide preliminary information regarding the effects of JD status on both herd and animal-level performance in Ireland.

View Article: PubMed Central - HTML - PubMed

Affiliation: Moorepark Dairy Production Research Centre, Teagasc, Fermoy, Co, Cork, Ireland. Esther.Richardon@maf.govt.nz.

ABSTRACT
Johne's disease (JD) is caused by infection with the organism Mycobacterium avium spp. paratuberculosis, leading to chronic diarrhoea and ill thrift in adult cattle. JD is considered to adversely affect farm performance and profitability. This retrospective case study was undertaken on a single commercial dairy herd in the south west of Ireland. Animal production records were interrogated to assess the effect of JD on milk yield (total kg per lactation), somatic cell count (the geometric mean over the lactation), reasons for culling, cull price and changes in herd parity structure over time. JD groups were defined using clinical signs and test results. One control animal was matched to each case animal on parity number and year. Specific lactations (clinical, pre-clinical and test-positive only) from 1994 to 2004 were compared between JD case and control cows. A significantly lower milk yield (1259.3 kg/lactation) was noted from cows with clinical JD in comparison to their matched control group. Clinical animals had an average cull price of €516 less than animals culled without signs of clinical disease. In contrast, little effect was noted for sub-clinical infections. These direct effects of JD infections, in combination with increased culling for infertility and increasing replacement rates, had a negative impact on farm production. Results from this study provide preliminary information regarding the effects of JD status on both herd and animal-level performance in Ireland.

No MeSH data available.


Related in: MedlinePlus

The temporal trend in the number of cows in the study herd, by parity.
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Figure 3: The temporal trend in the number of cows in the study herd, by parity.

Mentions: During the study period, infertility and JD culls (which only included animals culled due to the JD control programme from 2002-2004) were the main reasons for culling (Table 1), accounting for 31.3% and 28.3% of culls, respectively. Table 1 displays the influence of all other culling reasons: abortion, accident, bad legs, damaged udder, late calving, low production, mastitis, old age, other reasons, pining, slow milker, surplus and TB. Infertility had a steady influence on culling decisions throughout the study period (Figure 2). However, infertility was a more frequent reason for culling at the start, compared to the end, of the study period (Figure 2). High counts of 'other reasons' seen in 1996, 1997 and 2001 were all due to a high number of animals culled as 'surplus' in these years. The temporal trend in the number of cows by parity (1, 2, 3, 4+) is presented in Figure 3. There is evidence of a steadily increasing replacement rate over the study period, particularly post 1999, when parity one animals make up the largest parity group on the farm. Figure 3 highlights the dramatic switch in parity structure in the herd over the study period.


Direct and indirect effects of Johne's disease on farm and animal productivity in an Irish dairy herd.

Richardson E, More S - Ir Vet J (2009)

The temporal trend in the number of cows in the study herd, by parity.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113779&req=5

Figure 3: The temporal trend in the number of cows in the study herd, by parity.
Mentions: During the study period, infertility and JD culls (which only included animals culled due to the JD control programme from 2002-2004) were the main reasons for culling (Table 1), accounting for 31.3% and 28.3% of culls, respectively. Table 1 displays the influence of all other culling reasons: abortion, accident, bad legs, damaged udder, late calving, low production, mastitis, old age, other reasons, pining, slow milker, surplus and TB. Infertility had a steady influence on culling decisions throughout the study period (Figure 2). However, infertility was a more frequent reason for culling at the start, compared to the end, of the study period (Figure 2). High counts of 'other reasons' seen in 1996, 1997 and 2001 were all due to a high number of animals culled as 'surplus' in these years. The temporal trend in the number of cows by parity (1, 2, 3, 4+) is presented in Figure 3. There is evidence of a steadily increasing replacement rate over the study period, particularly post 1999, when parity one animals make up the largest parity group on the farm. Figure 3 highlights the dramatic switch in parity structure in the herd over the study period.

Bottom Line: In contrast, little effect was noted for sub-clinical infections.These direct effects of JD infections, in combination with increased culling for infertility and increasing replacement rates, had a negative impact on farm production.Results from this study provide preliminary information regarding the effects of JD status on both herd and animal-level performance in Ireland.

View Article: PubMed Central - HTML - PubMed

Affiliation: Moorepark Dairy Production Research Centre, Teagasc, Fermoy, Co, Cork, Ireland. Esther.Richardon@maf.govt.nz.

ABSTRACT
Johne's disease (JD) is caused by infection with the organism Mycobacterium avium spp. paratuberculosis, leading to chronic diarrhoea and ill thrift in adult cattle. JD is considered to adversely affect farm performance and profitability. This retrospective case study was undertaken on a single commercial dairy herd in the south west of Ireland. Animal production records were interrogated to assess the effect of JD on milk yield (total kg per lactation), somatic cell count (the geometric mean over the lactation), reasons for culling, cull price and changes in herd parity structure over time. JD groups were defined using clinical signs and test results. One control animal was matched to each case animal on parity number and year. Specific lactations (clinical, pre-clinical and test-positive only) from 1994 to 2004 were compared between JD case and control cows. A significantly lower milk yield (1259.3 kg/lactation) was noted from cows with clinical JD in comparison to their matched control group. Clinical animals had an average cull price of €516 less than animals culled without signs of clinical disease. In contrast, little effect was noted for sub-clinical infections. These direct effects of JD infections, in combination with increased culling for infertility and increasing replacement rates, had a negative impact on farm production. Results from this study provide preliminary information regarding the effects of JD status on both herd and animal-level performance in Ireland.

No MeSH data available.


Related in: MedlinePlus