April 2021 Monthly Management

Managing Butterfat Levels at Grass

Digestive upsets, Sub-Acute Ruminal Acidosis (SARA) and low milk fat are common issues in dairy cows at grass during this time of the year.

Lower milk fat can be due to several reasons. The first being a lack of fibre in the diet. This is often seen during the second-round grazing and short rotations of highly digestible grass being fed. If there is reduced fibre digestion, rumen pH is altered, disrupting the activity of the rumen microflora that produce the precursors of milk fat content. In the vast majority of cases, a prolonged absence of adequate fibre will lead to compromised rumen health and performance. Ultimately this will result in a reduction of milk butterfat percentage.

A second key factor for the occurrence of milk fat depression is an elevated intake of unsaturated fats from young, leafy grass. Unsaturated fats are toxic to rumen microflora and in order to survive, they carry out a process call “biohydrogenation”. This process produces by-products (saturated fatty acids) that in effect switches off the mammary gland from producing butterfat and thus milk fat depression arises. This effect can be exacerbated in the presence of a low rumen pH or if rumen health is poor (fibre availability, feed intakes, etc.).

Assessing the physical characteristics of the herd such as manure consistency is a simple indicator of rumen function. Dung stools should not be loose or watery but consistent like soft porridge.

Aside from butterfat depression, low rumen pH may also result in other significant consequences for the cow. Sub- Acute Ruminal Acidosis (SARA) is a common issue and can be addressed quite easily on-farm. SARA modifies rumen fermentation and less substrate for milk fat synthesis is available. SARA can also affect feed intake and impact on milk protein, yield and fertility. The way grass is managed and fed makes it a highly variable feed for cows. From a grass management point of view the following present increased risk of SARA: new pastures vs old pastures, changes in rotation (1st to 2nd to 3rd), dry matter of grass - wet lush grass is more problematic than dry grass. In addition, the management of grass can increase the risk of SARA. For example, under allocation of grass or grazing light covers that do not have adequate fibre content. Offering hay or straw can help provide some fibre in these scenarios.

Super Graze plus Rumbuff & Yeast

Super Graze is a 15% diet with a high inclusion of maize. It is almost a necessity to have a buffer included in your feed to counter some of the issues discussed in this article. This complimentary feed has Rumbuff and a live yeast as essential ingredients of the formulation. Rumbuff is a unique blend of slow release buffers that neutralise acid and does not change rumen pH. Because of this, rumen pH is maintained in the optimum range for longer periods. The added live yeast promotes rumen stability and digestion of fibre without disruption. Keeping the rumen function properly is key to feed intake, milk yield and optimising milk composition, particularly milk fat. Fertility booster mineral and Cal-Mag are included, balanced for 3kg feeding rates. Contact Sales representatives or Drinagh Mill for more information.

Grass Seed & Weed Control Brochures 2021

The Drinagh Weed Control Guide and the Drinagh Grass Seed brochure for 2021 are included in this month’s statement.

The grass seed brochure gives the varieties that make up the Drinagh grass seed mixes for 2021.

When considering soil type and future use of the reseed it is essential to select the right mix to get the best results for your farm. This information will help you to select the Drinagh grass seed mixture that best suits your needs.

The weed control guide gives information on what weeds each product will target, application rates, water rates and stock withhold periods. For further information on specific weed issues contact Tim/ Darren.

Grass & Grazing

The second round started on the 11th of April – covers are good on the farm with growth picking up now. Yvette does the grass measuring on the farm, with the most recent walk on the 13th of April showing an average farm cover of 821 kg/dm/ha and a growth rate of 41kg/dm/day. We are currently spreading 1.5 bags of 18-6-12 per acre on paddocks as they are being grazed.

Breeding will start on the 24th of April and we will use some sexed semen on heifers. In previous years, we have seen mixed results with sexed semen but recognize how important it could be in the future. Heat detection consists of tail paint applied with a radiator roller – tail paint is topped up weekly.

In terms of calving, we had a very good spring. Last year we had small issues with milk fever and retained cleanings. This is first year we used Dry Cow ration, we started Christmas week fed 2kgs per cow per day until the last cow calved, every cow has access to 2 feet of head feed space. Thankfully, we didn’t see any milk fever or retained cleanings this spring and the condition of cows calving down was excellent. We had a small problem with bloat in some calves on the automatic feeder, it was due to wrong calibration. Once we rectified the calibration we have had no issues since.