Analysis of lactating cows in commercial Austrian dairy farms: interrelationships between different efficiency and production traits, body condition score and energy balance

摘要

This study examines the relationship between efficiency, energy balance and related traits likemilk yield, feed intake (DMI), body weight and body condition score (BCS). Data was derived inthe project ‘Efficient Cow’ to develop efficiency traits for Austrian cattle breeding (6105 cows,161 farms, one-year data collection). The following efficiency traits were considered: bodyweight efficiency as ratio between energy corrected milk (ECM) to metabolic body weight, feedefficiency (kg ECM per kg DMI) and energy efficiency expressed as ratio between energy in milkto energy intake. The higher the proportion of Red Holstein (RH) in Fleckvieh (FV), the more(efficiently) milk was produced, but also at the expenses of body fat reserves. The negativeenergy state of Holstein Friesian (HF) and the FV groups with highest RH proportion lastedapproximately twice as long as of the least efficient Brown Swiss. All genotypes regained lostbody tissue during whole lactation. The high yielding groups required a higher concentrate proportion in late lactation to regain body condition. In early lactation, high efficiency was accompanied by the loss of body weight and BCS. Body condition stagnated longer on the lowestlevel and was more conform to energy balance than body weight. In conclusion, high efficiencyrequired an increasing partitioning of nutrients to milk yield inclusive mobilisation. Breeding forhigher efficiency would exacerbate catabolic state including problems with health and fertility.This highlights the necessity of a broader definition of efficiency in cattle breeding involvingparameters like BCS, health and fertility traits.