Farm Ireland

Friday 23 March 2018

Dairy: Surplus grass on grazing ground a Catch 22

Mary Kinston

Showery weather from mid-June to July has seen grass growth continue to forge ahead.

However, grass quality has continually required remedial work as the grass seed head vigorously appeared in pasture.

In certain parts of the country removing surplus bales as a mechanism to manage grass quality has been a significant challenge where there hasn't been two dry days together. If this surplus grass is on the dairy grazing ground it can become a 'catch 22' situation.

Trying to be patient and leaving the grass surplus for good weather reduces bale quality and prolongs a higher grazing demand and risks a potential grass deficit in subsequent weeks. Occasionally you can wait no longer and wet bales just have to be made.

Another issue many farmers have commented on this year is how their milk protein percentage is tracking behind last year by around 0.1pc. Obviously this is financially disappointing when milk price schedules are component based.

A variety of factors such as nutrition, age, genetic merit and breed will affect the shape of the lactation curve, and milk composition achieved.

Personally my gut feel was that the seasonal variation of 2015 may have promoted higher milk protein percentage or on the other hand the tough April of 2016 followed by grass seeding from May onwards may have disfavoured this year's protein percentage. Essentially for a spring calving herd, the stage of lactation on milk yield and milk composition is confounded with the effects of the different seasons.

However, there is nothing like reviewing the facts. Data which is shown in the table, looks at the milk composition of around 80-90 farms per year over the last five years.

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In 2011 and 2012 it seemed as if milk protein was stuck at around 3.5pc, whilst milk fat increased by 0.07pc to 4.16pc. The increase in milk fat percentage continued with a gain of between 0.05 to 0.07pc per year. In 2013, milk protein also jumped by 0.06pc to 3.56pc, and by a further 0.06pc to 3.62pc in 2014. In 2015 the gain was another 0.07pc to 3.69pc.

Maybe my first assessment of the impact of the year is wrong. However, the important thing to note is that for the members of my discussion groups these improvements in both milk protein and fat are substantial. Now there would be a strong focus on improving genetic merit and bull selection for both milk production and fertility which may be driving these figures.

As shown EBI increased from €114 to €166 over the five year period. There is also a degree of cross breeding within some herds, which also would increase milk constituents - especially as the herd ages. However, I would suggest that management improvements have also impacted on these gains in constituents.

Improvements in herd management on many levels - be it herd health, body condition score at drying off and calving, compact calving, spring grazing allocation and feeding, and especially the mid-season management of grass quality - all have their roles to play.

Environmental factors have a large influence in determining milk yield and constituents. Energy intake is the most important factor influencing milk protein. If energy intake is depressed through poor quality pasture or forage, by not allocating sufficient feed or by heat stress, then milk protein content will be depressed.

Therefore, maintaining pasture quality in mid-lactation is an essential driver of milk protein content. So your pursuit to re-establish good quality grazing on the platform, whilst challenging in this showery weather, is worth the effort.

After peak lactation, milk fat and protein will rise slowly with significant rises as the cow becomes heavily pregnant as we draw closer to the end of this year's lactation. So we will have to see what 2016 milk protein percentage will finish up at and whether these increases in constituent levels can be sustained or will tail off.

Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Co Kerry

Indo Farming