Hold your nerve and avoid adding silage if possible

In recent weeks it's as if grass growth has lost some momentum as above average growth rates scaled back and are now in many places only sustaining cow demand - if not a little behind in places.
In recent weeks it's as if grass growth has lost some momentum as above average growth rates scaled back and are now in many places only sustaining cow demand - if not a little behind in places.
Danny and Stephen Kane from Kilskyre, Co Meath at the tractor run in Crossakiel, Co Meath in aid of the 'Chloe Standing Tall Charity'. Photo: Seamus Farelly

Mary Kinston

Cows are now fulltime at grass and progressing through, or coming to the end, of the second grazing rotation on grass-based systems.

It's amazing how soon the soul heals when fine weather is upon us, with the woes of poor grazing conditions in March fading into a mere distant memory.

Optimism starts to make you feel that this good weather will last for the rest of the year. Who knows ultimately? Mother Nature always likes to remind you who is boss.

The first grazing rotation saw sustained high grass growth rates and for a while I was concerned that in a few cases farmers were failing to lower covers adequately. This could have resulted in a loss of quality and the need to cut silage from extra-strong paddocks.

However, in recent weeks it's as if grass growth has lost some momentum as above average growth rates scaled back and are now in many places only sustaining cow demand - if not a little behind in places.

I'm sure as the plants' desire to seed kicks in, and where adequate fertiliser is out, grass growth rates will soon forge ahead.

Where grass availability is tight on a farm, this is the time to hold your nerve and avoid introducing silage if at all possible.

A tight second round will provide you with the opportunity to establish good grazing residuals and promote grass quality and productivity for the rest of the year.

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Taking action to introduce forage should only be considered where pre-grazing yields consistently fail to reach greater than 1000kgDM/ha.

On the other hand where grass covers are heavy and grazing failed to get on top of the average farm cover, managing grass quality must be a priority and early cuts of silage may be the best option - otherwise, milk yield in terms of both litres and kgs of solids will suffer. This is especially true for the milk protein percentage.

The fact that March grazing was so challenging, with cows on and off grass, can still be seen in milk test results, with milk protein sitting around 3.3pc for many herds.

Milk protein is affected by genetics, stage of lactation, age, body condition, nutrition, and weather conditions. All of these factors can work independently or by interacting with each other.

The introduction of silage through March saw milk protein levels fall as energy intake was compromised. It's interesting to note that dietary changes will have a greater and quicker impact on milk fat content than milk protein.

Milk fat can be changed by 0.1pc to 1pc, with a depression in milk fat alleviated within seven to 21 days by changing the diet.

However, milk protein alters by no more than 0.4pc and may take three to six weeks, or longer, to recover once depressed.

As we get paid more for protein, higher levels of milk protein is financially beneficial so it's important to promote high quality pasture by good grazing management into mid-lactation. This will be an essential driver of milk protein content and profit over the whole lactation.

Therefore, the weekly farm walk and timely management of grass surpluses and deficits is essential to maximise the yield of milk protein produced.

The stage of lactation affects fat and protein percentages similarly. The highest amount is in colostrum, which falls after calving to reach a minimum level at around two months.


Percentages then increase slowly to a peak at 250 days at the end of lactation as milk production decreases.

Therefore, lower protein percentages recorded recently are in line with the present stage of lactation.

We all know production of milk fat and protein can vary tremendously between herds. Genetics and inheritance account for 55pc of the differences between cows, with protein and fat percentages being more highly heritable than yield of milk.

Milk solids obviously vary with breed. For example, Holsteins have the lowest fat and protein percentages, while Jersey and Guernsey cows have the highest.

Therefore, this year's breeding decisions will have a long-term impact on the herd's constituent levels. Make sure you look over these figures for improvement in solids content when selecting bulls for AI.

Another interesting point is the impact that milk protein has on the herd's fertility. As May draws nearer and the start of mating comes upon us, it's essential that cows are on a rising plane of nutrition in both grass availability and grass quality.

While milk protein does not cause poor fertility, numerous studies have shown that cows with a lower milk protein concentration at AI and during the whole lactation had lower submission rates and lower six-week in-calf rates.

Again, remember the importance of maintaining pasture quality and grass intakes as a means of ensuring cow fertility.

Weekly farm walks will help you manage your grass supply and quality. It is well worth the effort and time.

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

Indo Farming

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