A new somatic cell count index to more accurately predict milk yield losses
Intramammary infection and clinical mastitis in dairy cows leads to considerable economic losses for farmers. The somatic cell concentration in cow's milk has been shown to be an excellent indicator for the prevalence of subclinical mastitis. In this study, a new somatic cell count index (S...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-10-01
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| Series: | Archives Animal Breeding |
| Online Access: | https://www.arch-anim-breed.net/60/373/2017/aab-60-373-2017.pdf |
| Summary: | Intramammary infection and clinical mastitis in dairy cows leads to
considerable economic losses for farmers. The somatic cell
concentration in cow's milk has been shown to be an excellent
indicator for the prevalence of subclinical mastitis. In this study,
a new somatic cell count index (SCCI) was proposed for the accurate
prediction of milk yield losses caused by elevated somatic cell
count (SCC). In all, 97 238 lactations (55 207 Holstein cows) from
2328 herds were recorded between 2010 and 2014 under different
scenarios (high and low levels of SCC, four lactation stages,
different milk yield intensities, and parities (1, 2, and ≥ 3).
The standard shape of the curve for SCC was determined using
completed standard lactations of healthy cows. The SCCI was defined
as the sum of the differences between the measured interpolated
values of the natural logarithm of SCC (ln(SCC)) and the values for the standard shape of the curve for SCC for a particular period, divided by the total area enclosed by the standard curve and upper limit of ln(SCC) = 10 for SCC. The phenotypic potential of milk yield (305-day milk yield – MY305) was calculated using regression coefficients estimated from
the linear regression model for parity and breeding values of cows
for milk yield. The extent of daily milk yield loss caused by
increased SCC was found to be mainly related to the early stage of
lactation. Depending on the possible scenarios, the estimated milk
yield loss from MY305 for primiparous cows was at least 0.8 to
0.9 kg day<sup>−1</sup> and for multiparous cows it ranged from 1.3 to
4.3 kg day<sup>−1</sup>. Thus, the SCCI was a suitable indicator for
estimating daily milk yield losses associated with increased SCC and
might provide farmers reliable information to take appropriate
measures for ensuring good health of cows and reducing milk yield
losses at the herd level. |
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| ISSN: | 0003-9438 2363-9822 |