Low butterfat in milk is most common at springtime in lush grass, however the problem has continued towards the summer months and into the start of autumn across many Irish dairy farms this year. With milk prices not favourable at the moment, it is crucial improvements in milk quality is maximised.
To understand the background on how the problem manifests, it is worth noting the following: Butterfat deposition is compromised when highly digestible grass is offered with a high sugar content and low effective fibre. As a result, low acetate synthesis is common, leading to lower content of butterfat in the milk. In turn this will most likely lead to sub-acute ruminal acidosis (SARA) where the pH in the rumen is supressed to 5.5-5.6. This will have a major impact on feed intake and feed digestion leading to an overall milk depression together with effects on health. The failure to maintain a consistent rumen pH in high yielding dairy cows will result in a greater likelihood of a metabolic disorder.
In order to offset this problem I make a number of recommendations to farmers. The diet offered is the key for moderate butterfat levels in milk. The overall objective is to maintain a stable pH to have maximum fibre digestion. Careful attention must be directed towards sward quality in the promotion of adequate long fibre that will increase the production of acetic acid in the cow’s rumen. This is critical for rumination and the effect of chewing; producing saliva to maintain a good rumen pH.
High-Energy High Fibre
To increase the likelihood of fibre in lush grazing areas following silage harvesting (particularly relating to second cut at this time of year), it is important high digestible structural fibre is offered in the form of soya hulls, beet pulp, citrus pulp. This can be offered in the milking parlour solely or as a concentrate, paying particular attention to the list of ingredients in descending order. I would recommend either the 14% or 16% high-energy high fibre dairy cube feed from Connolly’s RED MILLS to minimize the depression in milk fat during the autumn period.
Buffer feeds are also an option to maintain a high dry matter intake with high proportions of structural fibre in the form of chopped straw and digestible fibre sources. However careful attention must be directed toward this scenario as the objective is to allow cows consume some buffer feed without compromising grass intensity. The aim here is to limit the effect of SUBSTITUTION of a buffer feed for grazed grass.
The use of rumen conditioners is also a very good tool to maintain volatile fatty acids (VFA) in the rumen together with yeasts which can help maintain the pH of the rumen, limiting the chance of SARA in dairy cows at grass. It is also important to note that protected fats can also lead to an increase in milk butterfat concentration.
Last but not least, it is very important that the body condition of dairy cows is between 2.5-2.75 during lactation. Anything below a body condition of 2.5 will have an impact on milk butterfat together with health and reproductive performance.
In summary I cannot overstate the effect the diet has on milk fat depression, however using the above strategies will help in the promotion of greater butterfat levels of your cows in the autumn period. If you are looking for more advice and information on improving the quality of your milk, you can ask one of our experts for more information.
- Body Condition Scoring