Evaluation of the performance of dual-purpose cows in European pasture-based systems

Summary

The demand for organic products in Europe is growing, especially organic products of animal origin. Organic dairy milk production requires grazing of cows, which results in a feed ration that is pasture-based. The breed that is kept by far the most for dairy production in Europe is the Holstein Friesian cow, a high-yielding dairy cow. This cattle breed has been developed in North America and was selected for its high milk yield. The disadvantages of this one-sided selection for production manifest in the health, fertility and longevity of the cow. More important, the high milk yield of the Holstein Friesian is only achieved when the cows are fed a diet of high quality and especially concentrates, which is not always possible in a pasture-based system.
In this study the alternative for the Holstein Friesian breed is considered, namely the dual-purpose cow. Most countries feature indigenous cow breeds which were traditionally kept for both milk and meat. Because of the popularity of the Holstein Friesian breed these local breeds are less used in dairy production systems. An extensive literature study was carried out to compare the popular Holstein Friesian breed to the local dual-purpose cattle breeds. This showed that local dual-purpose breeds display in many traits such as health, fertility, meat quality and longevity an advantage over the Holstein Friesian. Additionally, dual-purpose cows are better able to cope with a harsh environment and a diet of low quality.
Furthermore, the grazing behaviour of one of the Dutch dual-purpose breeds, the Dutch Friesian, was compared in the current study to the Holstein Friesian. For this purpose the monitoring system SensOor (AGIS) was used. SensOor registers the four main conducts of the cows, namely eating, ruminating, resting and other activity (such as walking, standing, etc.). The system expresses the time the cows spend on these conducts in percentages per hour or per day. In this study the SensOor system was validated under grazing conditions for the first time. Before, the SensOor system was only validated indoors or in a dirt pen. The validation under grazing conditions was done by observing the behaviour of the cows on the pasture, and comparing these observations with the SensOor output. The observation of the activity ‘grazing’ corresponded very well with the detection of the activity ‘eating’ (R² = 0.97). As the validation of SensOor under grazing conditions was successful, the output of the system was used to compare the behaviour of the two cattle breeds. In the current study no significant differences in behaviour were found, which can be explained by the differences in size of the cows (HF: 650 kg, DF: 575 kg) which have therefore different energy requirements. Another explanation could be that the high quality of the grassland on the studied farm concealed the ability of dual-purpose cows to cope with low-quality roughages.
Besides the study of the behaviour of the cows, the herbage production on two farms was estimated. This was done by the placement of grass cages on the pastures. The herbage growth under the cages was mown, weighed and analysed.
In conclusion, the monitoring system SensOor is very suitable to monitor the grazing time of cows. The literature study showed that dual-purpose cows have advantages over the Holstein Friesian (especially in milk composition, meat quality, health and longevity). Concerning their grazing behaviour, dual-purpose cows might spend more time on grazing and constitute more grass in their diet. This difference in behaviour was not shown by the output of SensOor. The absence of this difference might be explained by the excellent environment of the Friesian pastures. It is expected that the advantage concerning grass and feed intake of dual-purpose cows are better demonstrated in a harsh environment with pastures of low quality.