Beurteilung der Konstitution von Milchkühen anhand der Ausprägung ihrer wesentlichen arttypischen Eigenschaften

Summary

Over the past 40 years, dairy cow breeding has led to very high yielding cows (more than doubled average annual milk yields in most dairying countries), but also to a deterioration in cow health, fertility and longevity (Pryce et al. (1999)). Consequently, many breeding organizations all over the world are seeking to include functional traits in their breeding programmes (Groen et al. (1997), Christensen et al. (1998)). A great amount of research is done on potential index traits for indirect selection for health traits (Groen et al. (1997)). The whole constitution of the animals is to some extent considered in Scandinavian breeding programmes using the epidemiological data of all herd book animals (Philipsson et al. (2000)) and in breeding for life time dairy performance (Haiger (2000)).
Our working hypothesis is that animal constitution has to do with the intensity of their species-specific character and expression. We propose to develop an evaluation model by comparing the vertebrates’ early embryonic states and their embryonic development: All vertebrates exhibit quite similar early embryonic states. Species-specific differentiation appears during later embryonic development. The specialization of the organ systems occurs with different intensities for each species resulting in different “morphologic valencies” (Portmann (1983)). The “morphologic valency” derives from the degree of differentiation of the organs (Portmann (1983)). It is possible to group the organ systems in a metabolic-limb-system, a rhythmic system (blood circulation and respiration) and a nerve-senses-system (after Schad (1971) and Steiner (1917)). Most animal species develop one of those three organ systems to a great extent. Ruminants develop highly specialized limbs and a highly differentiated digestion system: their four stomachs and their intestinal organs are more complex than those of all other mammals. Their life is dominated by these organs: dairy cows spend at least two thirds of a day eating and ruminating. Animal welfare is strongly influenced by the state of health of those specialized organs. Many cow diseases correlate with imbalances in the digestion system (Lotthammer (1992), Spranger (1998)). To assess animal constitution we propose giving special attention to physiology and behaviour with respect to these highly specialized organs and to the corresponding temperament (most animals with a highly specialized digestion and metabolic system tend to have a calm disposition (Marek et al. (1956)). We are thus looking for links between health, ruminating behaviour, metabolic and digestion parameters and temperament of dairy cows. Such observations need to be done under appropriate animal husbandry conditions.
60 dairy cows on a biodynamic farm in Switzerland were observed in terms of ruminating behaviour (ruminating time per day and per ruminating period, frequency of ruminating periods per day, jaw movements per bolus, chewing time per bolus, ruminating speed), body condition score (BCS after Ferguson et al. (1994)), manure consistency and temperament (nervousness / calmness while being brushed by an unknown person). Most methods for these observations had to be developed (Schneider (2002)). The records thus gained were correlated to the health parameters of the same cows (disease incidence, somatic cell score; methods for this were developed by Silvia Ivemeyer).
The cows exhibited individual differences in all parameters. Multiparous cows chewed less and slower than primiparous cows. High yielding multiparous cows chewed less than lower yielding multiparous cows. Chewing time per bolus correlated negatively with mastitis incidence. Nervous cows exhibited higher somatic cell scores and a tendency to higher disease incidences than calm cows. Standard deviations in BCS correlated with metabolic diseases, claw diseases and reproduction problems. Evaluations are ongoing.