While monitoring the feed efficiency of beef production is quite common, dairy farms worldwide have been slower to catch on. Efficiency monitoring stands to gain ground in dairy, particularly with the recent demise of the 31-year-old milk quota system in Europe that promises to unleash significant competitive pressures across the industry.
Delivering dry matter
Efficiency is typically calculated as a ratio of output to input. For dairy, the measure is milk yield over dry matter intake (yield/DMI), where the higher number, the better. For beef the formula is reversed: dry matter intake over average daily gain (DMI/ADG), where a lower figure means greater efficiency. In both cases delivering dry matter for consumption is crucial. On most dairy farms crop feed produced on farm accounts for the majority of the total mixed ration (TMR) while the rest comprises mainly purchased concentrates. The efficiency of turning crop production into taken up feed is often overlooked.
Yet, the difference in effective delivery of dry matter through efficient versus inefficient methods can vary considerably. Figure 1 shows how an initial crop yield of 1000kg dry matter incurs losses at each step in the silage and feeding process before reaching the animal. This example assumes good soil management, which can influence crop yield, as the starting point. Overall, an efficient silage harvest, storage and delivery process will lose 10% of dry matter while an inefficient one will lose more than 50% due to wastage and spoilage. A closer look at the types of losses that occur at each stage reveals strategies to conserve dry matter.
Figure 1. Two scenarios for total dry matter losses.
Types of dry matter losses
Harvesting leads to field losses ranging from 3% to 10% of crops.
Fermentation losses always occur when making silage, though these range from 2% to more than 10%. By providing greater and faster production of lactic acid that lowers the pH value, Biomin® BioStabil prevents spoilage organisms from taking hold and thus improves silage quality. In trials Biomin® BioStabil has been shown to reduce dry matter losses by up to three percentage points (Figure 2).
Figure 2. Biomin® BioStabil reduces fermentation losses.
Once the silage is exposed to oxygen, yeast and mold can become active and cause feed-out losses of up to 30%. Molded silage is easily identified and discarded. Yeast consumes high levels of valuable nutrients such as sugars and lactic acid, withdrawing both dry matter and energy.
Biomin® BioStabil also reduces the yeast and mold count by a factor of 10 to 10,000 (Figure 3). The different heterofermentative bacteria strains in Biomin® BioStabil produce acetic acid and hinder yeast and mold growth.
Figure 3. Reduction in yeast and molds using Biomin® BioStabil.
The number of yeast cells in silage is normally not measured on farms, so on farms increased silage temperature is often the only indication of yeast growth. Aerobic stability – the time it takes for silage temperature to rise two to three degrees Celsius above ambient temperature – is a good way to measure the quality of silage after exposure to air. Figure 4 provides results of trials that show Biomin® BioStabil can extend silage storage life by two days for grass and more than five days for corn (maize).
A number of additional measures can help reduce feed-out losses, including maintaining anaerobic storage, good compaction to lessen the exposure to air, a high feed-out rate (making fast progress into the silo), achieving the optimal dry matter percentage and using appropriate removal techniques.
Getting the feed to the animal relies on accurate feed distribution. A modest level of feeding losses will occur. Lactating dairy cows should always have access to feed, so feed leftovers of 3% to 5% are normal.
Benefits to the animal
The end result of efficient dry matter delivery along these steps is more and better quality feed with higher energy and protein levels and more palatable feed. As a consequence, use of a silage inoculant such as Biomin® BioStabil has been shown to improve dairy feed efficiency in the animal by 1% to 3% (Figure 5).
Figure 5. Feed efficiency gains with Biomin® BioStabil.
Kiwi case study
In New Zealand dairy production often fully relies upon grazing. Because less feed is purchased there the traditional way to measure feed efficiency is calculated as the quantity of milk solids (kg of fat plus protein) per hectare. Interestingly, this is essentially a holistic view of the dry matter delivery and conversion processes.
Feed efficiency is one parameter of gut performance management. As competition in the cattle industry mounts, feed efficiency will play a greater role. The traditional definition looks at conversion of dry matter within the animal. A holistic view of feed efficiency that encompasses all steps from crop production to dry matter conversion can offer broad improvements through less waste and improved output, with both economic and environmental benefits.