The association of herd performance indicators with dairy cow longevity: An empirical study

Abstract

The associations between reproductive performance, milk yield and health status with the risk of culling, and thus with a cow’s longevity, have been well documented at the individual cow level. Associations at individual cow level may, however, not be valid at herd level due to interrelated herd management aspects and/or policy restrictions. The objective of this study was to explore the association of herd performance indicators with herd-level dairy cow longevity under Dutch production conditions. Longevity was expressed by three different measures, viz. age at culling, lifetime milk production of culled cows and culling rate. The evaluated herd performance indicators included factors on milk production, youngstock rearing, reproduction and health performance as registered on 10 719 Dutch commercial dairy herds during the period 2007–2016. Averaged over herds and the evaluated period, the age of culled milking cows was 2 139 days (5.8 years, SD±298 days), the lifetime milk production of culled cows was 31 238 kg (SD±7,494 kg), and the culling rate was 0.24 (SD±0.08). A mixed linear regression modelling approach was applied to evaluate the association of each of the three longevity measures with the selected herd performance indicators. The results indicated that only four herd performance indictors (herd size, herd expansion, heifer ratio and the proportion of cows with potential subclinical ketosis) shared significant associations with all three longevity variables. Generally, the strength of the associations between each of the evaluated longevity measures and herd performance indicators was only limited. The absence of strong associations between the longevity measures and herd performance indicators reveal that there is potential of extending cattle longevity without affecting the herd performance in terms of milk production, reproduction and health. Moreover, only part of the observed variance in longevity among the herds over time was explained by the herd performance variables, indicating that differences in longevity at herd level may predominantly be determined by other factors, like farmers’ attitude and strategic management.

Dairy cattle replacement under changing agri-environmental policies

“…The total replacement rate was comparable to the national culling rate reported by CRV (CRV, 2021b) of 28% in the year 2020-2021 from which most of the inputs were defined. Similarly, several studies, reported an average culling rate of 25% in the Netherlands in the past two decade which was slightly lower than the results of our base scenario (Han et al, 2022;Nor et al, 2014b) From the sensitivity analyses (Table 5.3), it was clear that the base scenario was sensitive to the economic inputs such as milk prices, carcass value and heifer rearing costs but not to the feed costs. This showed that the consequences of changes in market prices could change the optimal policy for replacement regardless of constrained heifer supply, which agreed with the findings of Demeter et al (2011) and, Kalantari et al (2010.…”

“…and farm-specific characteristics (Alvåsen et al, 2012;Han et al, 2022;Nor et al, 2014a) but these associations did not completely explain the variation in culling magnitudes or reasons for culling between different farms. Nor et al (2014) pointed out that the majority of studies on culling reasons focus on the performance of individual cows whereas the farmer's style, culture and individual herd management might play a role in culling decisions as well.…”

“…Often, dairy cows are culled due to multiple reasons, while only the primary reason gets recorded in the database (De Vries and Marcondes, 2020;Pinedo et al, 2010). Culling reasons on herd level are different and more related to managemental aspects such as strategies of farmers, herd average milk production, structure of herd, style, and behaviour of farmers (Beaudeau et al, 1996;Han et al, 2022;Nor et al, 2014a;Vredenberg et al, 2021). Moreover, it has been shown that culling reasons differ between primiparous (1 st parity cows) and multiparous (> 1 parities) cows (Gussmann et al, 2019).…”

“…Therefore, to improve the longevity of dairy cows, efficient management and culling are important (Schuster et al, 2020). Han et al (2022) discovered that longevity on farms could be improved without impacting herd performances to a large degree. Further research into the perspectives behind the culling strategies of dairy farmers, and their intentions to alter these strategies in near future is needed.…”

“…In the Netherlands, the average annual replacement rate has been varying between 20% and 30% in the first two decades of the 21 st century (CRV, 2019;Nor et al, 2014a). This means that dairy cattle longevity in the Netherlands of 5.8 years is far below the biological potential lifespan (Han et al, 2022). These replacements can be either due to economic reasons (voluntary) or due to health considerations, hence involuntary .…”