RZFeedEfficiency: Maximise feed utilisation - reduce costs

Responsible use of scarce resources is also a key component of climate and environmental protection in agriculture. Dairy cows consume more than 20 kg of dry matter silage or grass per day. Even though ruminants eat and utilise a large proportion of plant parts inedible to humans, making the most efficient use of feed can help conserve resources and reduce costs. How well a cow can utilise the feed she consumes and convert it into usable energy also depends on her genetic disposition.

The new RZFeedEfficiency therefore makes an important contribution to conserving resources.

The new RZFeedEfficiency describes how much less or more feed (kg dry matter) a cow consumes for her production compared to what is expected. Productive performance is not only the milk yield as ECM (energy corrected milk), but also the carcass gain which ultimately generates income when the cow is slaughtered. RZFeedEfficiency is averaged over 3 lactations and therefore represents the productive life of the cow.

Expected feed intake is calculated using estimated breeding values for Dry Matter Intake (DMI), Energy Corrected Milk (ECM) and Body Weight Change (BWC). An energetic evaluation of an animal's performance (ECM, BWC) is performed to convert it into feed equivalents or kg dry matter (DM). This is done using key figures from feeding guides and our own calculations. An energy content of 7.0 MJ NEL per kg DM of a TMR was assumed for high yielding Holstein cows. This means that an animal requires 0.4 kg DM to produce 1 kg ECM or 4.5 kg DM to produce 1 kg of body gain. This conversion can then be used to determine the amount of feed saved or overfed for the observed performance of an animal.

Christin Schmidtmann (vit)

The trait feed efficiency is largely independent of other traits, including RZG and RZ€. As a result, there has been no positive development in this trait in recent years. This means that breeding for higher milk yield has led to a corresponding increase in feed intake.

There is, however, a clear correlation with the body traits and therefore the weight of the animals. Due to the slight to moderate negative correlation, slightly smaller and therefore lighter cows are more efficient than large and heavy cows.