Higher yielding herds – to graze or not!

Date published: 27 August 2024

Turnout was delayed due to a wet cold spring and for some in the west, unseasonally high rainfall through June, July and August made grazing particularly difficult while for others, predominantly in the east, lack of rain and resultant grass growth through June and July made buffer feeding necessary.

Recent years have seen more and more cows being housed over the summer months. This may have been because herds have outgrown the available grazing area, and for some it may be that grass and grazing is simply no longer seen as fashionable, while for others it may be the perception that grass is no longer a suitable feed for higher yielding cows with its variable quality and dry matter.

In South Down currently (August 2024) a lot of cows are ‘at grass’ and the performance of those who record using the CAFRE MOC recording is shown in Table 1.

Table 1 Current performance of some County Down herds using CAFRE MOC recording

Table 2 Rolling performance of herds in table 1

Many factors must be considered when grazing cows but two of the biggest challenges involve:

1. Achieving the highest possible grazing intakes while at the same time maintaining grass quality throughout the grazing season
2. Setting realistic performance levels (M+) that can be achieved before concentrate supplementation

Maximising intake versus maintaining grass quality

The aim should be to offer cows upright, dense, palatable swards of grass on a consistent basis, constantly balancing grazing pressure and sward growth. Ideally cows will be turned into pre-grazing covers of 3,000 – 3,200kg DM/ha to maximise intake/bite and be taken out at covers of 1,800 – 1,900kg DM/ha (6-8cm). If cows are offered this grass, then intakes of 15-16kg DM/head/day can be achieved and this has the potential to support milk levels of 18 - 20 litres at peak for a spread calving pattern Holstein herd. To ensure cows are allocated the correct amount of grass each day walking and measuring grass covers on the grazing area on a weekly basis is very important. This enables any grass surplus or shortfall to be identified and action to be taken in a timely manner.

Sometimes both grass intakes and quality are overestimated, with the result that cows are underfed concentrates leading to a drop in milk yield and, if left unchecked, body condition. Very often grass will be blamed! In the South Down area, grassland farmers are saying that grass today can maintain (M) the cow and produce 12-14 litres of milk (some will aim higher) and are supplementing cows at a feed rate of 0.45kg/litre for every litre over this. Most will be expecting that heifers will produce 2-3 litres less from grass than mature cows. These levels of performance assume both good grass intakes and quality. As the season progresses and grass quality declines these M+ figures will obviously be scaled back and ending the season at 10 litres or less.

Case study – David and Andrew Murray

Andrew, along with his father David, runs a Holstein/Friesian herd on a grass only farm near Ballyroney , Co. Down. The rolling performance figures of the herd are 8455 litres sold/cow/year with 3498 litres of milk from forage and a concentrate input of 2.2 tonnes/cow/year. Like many herds, turnout was delayed until 28^th April with cows out by day and night a week later. The herd is tight Autumn calving and presently averages 270 days in milk with a third of the herd already dried off. Current performance is 24.5 litres/cow/day, at 4.25% butterfat and 3.60% protein, from 3.75kg of a 16% concentrate meaning 15 litres of milk is being produced from grazed grass. Regular reseeding is carried out to ensure cows are always presented with top quality grass, or in the winter months, grass silage. Andrew finds dry matter intakes are key to achieving high levels of performance and so cows are given access to fresh grass after each milking and normally would be ‘going into’ covers of 3,400 kgDM/ha and ‘coming out’ leaving a residual of 2,000kgDM/ha. Pre mowing is practised to again encourage dry matter intake. It is not just cows which have access to quality grass as 2023 born calves are grazing young leafy swards full time with ½ to ⅔kg of concentrate supplementation. In-calf heifers are likewise grazing full time on a grass only diet. The farm has a rolling replacement rate of 22% with heifers calving in at 24 months and cull cows leaving the herd having achieved an average lifetime performance of 43,150 litres of milk. Andrew feels that in order to have an efficient sustainable dairy business he wants a cow which produces quality milk (high solids), has the ability to consume large amounts of both grazed and conserved forage, has good fertility and lasts in his herd. In recent years some Friesian semen has been introduced with ¾ Holstein: ¼ Friesian heifers and cows currently performing very well in the herd. Bulls such as Westcoast Almamater, Bomaz Fynn, Seagull Bay Applejax and Bomaz Vader have been used recently.

Grazing – is it for me?

Maybe you have read this article and think it all sounds like a lot of hard work when you could simply keep the cows in the house on a consistent diet with every day being the same. The Murray family prove that high yielding herds can be grazed successfully. But just as importantly - what about the cost? Can you afford not to be making use of the best quality feed on your farm which also is the cheapest feed on your farm? A herd of 100 cows at grass full time, could possibly be saving £120/day in diet costs compared to a similarly sized housed herd. Can you afford to miss this opportunity?

If you would like to discuss grazing potential in greater detail, contact your local CAFRE dairying development adviser.