Ten years evolution of dairy cattle herds: fertility, production and management

Abstract

This study described the productive data evolution from 71 dairy herds over ten years (2008 to 2017). During this period, two global management strategies changed: timed Artificial Insemination (AI) programs since 2011 onwards and composting bedding systems since 2014. The results showed an increase of total cows/ herd (293±299 in 2008 vs 498±558 cattle in 2017), and maximal herd size (980 in 2008 vs 2,505 cattle in 2017). The percentage of heifers (based on the total of animals) was 69.0% without a tendency of change over the years. Regarding production, average daily milk yield per lactating cow increased with time (30.3±2.5 in 2008 vs 33.5±2.2 l/cow in 2017). While calving to first AI interval and estrous detection rate remained stable (91 days and 51.2%, respectively), average days in milk decreased with time (204±14d in 2008 vs 195±16d in 2017). Similarly, the total of AIs per pregnancy decreased from 4.4±1.2 in 2008 to 3.6±1.1 AI/P in 2017. Accordingly to these data, conception and pregnancy rates increased (CR=28.7±5.0% and PR=15.0±3.5% in 2008 vs CR=32.0±5.6% and PR=16.4±4.3 in 2017). Age at first AI decreased from 16.1±1.4 m of age in 2008 to 14.8±51.5 m in 2017, with a reduced age at first calving from 26±1.7 m to 25.1±1.6 m of age in 2017. Neonatal mortality was 8.5%/year during the whole period, with a minimum of 7.2% in 2013 and a maximum of 13.4% in 2008. The annual percentage of culled cows remained stable (29.1±6.8 in 2008 vs 29.8±7.2% in 2017). Dry period length decreased from 64±10 in 2008 to 62±9d in 2017, without an apparent decreasing tendency over the period. In conclusion, the increase in the size of farms is confirmed during this ‘after milk quota period’. The historically impaired fertility with an increasing individual production could not be observed. Moreover, cow’s fertility and heifers reproductive efficiency (age at first calving) improved during this period.