Brian Reidy: Changing grass silages and balancing it this winter
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All cows and cattle take an average of 21 days to adjust fully to any new diet formulation or new ingredient introduced. The animal’s rumen bug population needs that time to increase in numbers in order to be capable of breaking down the new nutrient profile of the diet. December is often a time when there is a change of silages on the farm. This year many have been using up available bale silages before opening pits and as a result, many are moving between different silages. Take care when moving over to pit silage as it tends to be lower in dry matter and more finely chopped which can cause temporary digestive upsets. Many farms are reporting loose dungs in stock during this transition over to different silages.
As changes in silage supply occur, nutrient supply changes depending on the profile of the new silage. When you change, it is important to adjust the balance of the diet accordingly. Overfeeding energy or protein will result in excessive costs and possibly poorer animal performance. The overfeeding of animals that are not capable of increased performance is also wasteful. If animals can’t increase performance with extra feeding, then it goes to waste or can be detrimental to performance, depending on what you are trying to achieve. Too much energy in maiden heifers may result in them being more difficult to get in calf, while too much protein may also cause similar issues. In many cases, the bales that were made later in the year will be better quality than the pits, so an increase in supplementation may be needed along with the change in silage. Good silage will always reduce production costs, poor quality will do the opposite- Planning for silage 2025 should start now.
Analysis of silage for minerals is becoming something that many farms now get done yearly. Again this winter we have seen results throw up some interesting and unwelcome trends. Many silages are high in antagonists such as Lead, Aluminium, Iron and Molybdenum. Soil contamination is also a contributory factor. It has been shown that these elements tend to be high in years where water tables may have been high in the winter and into the spring. These antagonists make it more difficult for animals to extract important minerals such as Copper, Selenium, Iodine, Cobalt, Zinc and Manganese from the silages.
Testing for minerals in your silage will identify deficiencies and begin the balancing process for each animal group. If you have had issues with animal performance, with poor growth/gain and or fertility in the past, then minerals should be one of the aspects that you investigate further. This will help to identify deficiencies on your whole farm and will help you to design supplementation which may also include what your soil requires fertiliser and trace element wise.
Silage and grazed grass make up the predominant feed source on almost all Irish farms. If we know what level of minerals and vitamins an animal requires based on, genetics, age, weight and sex then you can get a mineral pack formulated to supply them with any elements deficient in the base feeds grown on your farm.
Particular symptoms may not be an indication of a specific deficiency. Use available science to establish the real story and get the balance right. Different geographical areas and soil types have particular mineral deficiencies.
Minerals help to drive animal performance, some are natural growth promoters, some are antioxidants, others drive an efficient immune response and are involved in many different pathways to insure a healthy and productive animal.
One way to help achieve better animal performance, less animal losses and fewer vet calls may be to concentrate more on mineral supplementation. This may be of considerable use during the dry period for suckler cows and in high-performing finishing stock. One issue which has been highlighted over the last few weeks has been the reporting of a lot of milk fevers and held cleanings in late autumn dairy cows. In almost all cases, these issues were not common in the early calving cows. It has been observed that many of the issues started as bale silage was replaced with 2nd cut silage in particular. These silages will have in many cases received a significant amount of slurry after 1st cut. Many of these silages have come back with lab results showing heightened Potassium levels. This has been in some cases coupled with high sodium levels. This will result in a high DCAD number and is an indicator of potential metabolic problems around calving. If this is an issue and cows are over-conditioned at calving, then trouble is not far away.
In order to optimise finishing performance, minerals must be fed. Don’t be drawn into the notion that they will be slaughtered soon. Minerals will prevent illness, injury and improve performance right up to slaughter.
Those feeding maize silage, whole crop and beet in particular need to make sure that they are supplementing with sufficient phosphorus.
