Consider options now to counter impact of late autumn grazing

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Length: 1019 words; 5-6 minutes

Grazing dairy cow

Good weather encouraged many to extend grazing last autumn. But there could be negative effects for spring milk production that need to be considered, states KW’s Charlotte Ward.

An additional 4-6 weeks of autumn grazing helped reduce early winter feed costs for large numbers of milk producers across the country, and provided a welcome lift to margins. But unless the weather this spring is favourable, many could lose half those gains to delayed turnout.

“A typical 200-cow herd requiring another fortnight of winter rations will consume an extra 56t of ration dry matter,” states KW nutritionist Charlotte Ward. “Even using the very best value feed options currently available, that adds up to nearly £9,000 in additional feed costs.”

According to Ms Ward, the challenge is that most herds were pushing hard to maximise production from grass through the summer and autumn, potentially overgrazing in some cases. And with many areas having seen virtually no rain for six weeks when cows were finally housed, and the weather quickly turning cold, there’s been minimal regrowth since.

“It means that winter covers may be significantly lower than normal,” she explains. “A lot depends on the weather, but it could delay spring regrowth by up to 2-3 weeks, and the required grass ‘wedge’ might not be there when the planned turnout date comes around.

“It’s a potential threat to spring feed costs and milk production that needs to be considered now, while there’s still time to adjust winter feeding plans to account for a possible later turnout, or if a more gradual turnout is needed to allow grass covers to build up.”

Autumn sward management

Reducing grass covers in the autumn to minimise ‘winter kill’ is important, but so too is creating the foundation for the spring grass wedge. Sequentially shutting up grazing areas and allowing some regrowth in those fields to be grazed first in the spring is critical, as is removing cows before grass cover gets too low.

“Current recommendations suggest a minimum post-grazing cover of 1,500kg DM/ha – around 4cm sward height – if grass is to respond quickly once temperatures begin to rise,” Ms Ward continues. “Not only were some grazing areas taken below this level, but the lack of regrowth since means that the entire grazing area could still be at, or close to, the same minimum level of cover.

“Particular care should also be taken if using sheep to manage winter cover levels, and they may well need to be managed more carefully this year. The same rules apply as for autumn grazing – shut up grazing areas sequentially to set up the spring grass wedge, and be very careful not to overgraze.”

Low body condition

Adding to the challenge is the impact of cows entering winter with lower than ideal body condition score (BCS). This will limit the extent to which mobilisation of fat reserves can help mitigate any reduction in grass availability following turnout.

“The pressure to reduce feed costs meant that most herds received less supplementary feed during the summer than normal,” Ms Ward adds. “In addition, grass energy levels were below the six-year average for most of the grazing season (figure 1).

Grass Energy Graph
Figure 1 – Grass energy levels during the 2016 grazing season (Source: Trouw Nutrition)

“It’s therefore important to check whether cows are still below target BCS – aim for 2.5 at peak lactation rising to 3.0 at calving – and when planning how to cover a potential delay to turnout build in some extra energy to get BCS back on track if needed.

“It might mean investing in additional feed now, but the alternative is that even greater pressure will be placed on nutrient supply from spring grass as cows look to regain body condition once grazing.”

Assessing silage stocks

Ms Ward’s advice is to start with an assessment of remaining silage stocks, including both estimated volumes and a fresh analysis of quality – if dry matters are lower than expected, for example, stocks can quickly disappear. It’s also important to work out a realistic estimate of when new crop grass silage will be available, based on current grass covers and the six weeks post-clamping needed for silages to stabilise.

“Most farms have plenty of grass silage, even if it has a lower feed value than they’d like, though there has been the occasional report of some being short of maize silage. So work out how much is needed for buffer feeding once cows are turned out, and adjust rations now if necessary.

“Increasing the proportion of grass silage fed and rebalancing the ration as needed is one option, with the confectionery and biscuit meal blends such as SweetStarch and SugaRich Dairy are generally better value than rolled cereals for any extra starch needed.”

If grass silages are acidic, or the ration is already high in starch, Ms Ward recommends considering the more rumen-friendly caustic soda-treated SodaWheat to help control the risk of acidosis. It can also be worthwhile splitting the herd if not already doing so, enabling early and mid-lactation cows to take priority to ensure their nutrient requirements are met, with any cost-saving ration changes limited to later lactation cows.

Additional feed requirements

 “It’s also worth checking contracted volumes for proteins to ensure there’s enough cover,” she continues. “Availability of mid-proteins remains tight, so additional forward contracts could be the best way to secure extra supplies of British wheat distillers’ feed, for example.

“Other options include the high protein liquid feeds like ReguPro 50 or Regumaize 44, with ProtoTec heat-treated rapemeal a more cost-effective alternative to soyabean meal for those needing extra rumen-bypass protein. And don’t overlook the value of moist feeds like Traffordgold as high-energy, mid-protein ration extenders, with Wessex Gold moist blend or apple pomace also worth considering in the south.”

The key is to have a contingency plan in place, claims Ms Ward, and see it as an investment to protect milk production throughout the spring and summer.

“You’ll then have the option to keep cows housed or turn them out for just 2-3 hours a day if that’s what’s needed to build grazing covers. Or bring cows back in if the weather deteriorates and you want to protect swards from poaching.

“Grass growth was slow for nearly everyone during spring 2016, so make sure you’re considering the implications of a repeat this year, particularly if you grazed hard and long during the autumn.” 

 

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