Dry off is under way, and SealesWinslow’s Nutrition Extension Specialist Simon Butler says the dry period is harder on cow condition than most feeding plans are accounting for.

He says the target at calving is a body condition score (BCS) of five for mixed-age cows and 5.5 for heifers. Getting light cows to those targets once they are dried off is an uphill battle.

“We have impaired dry matter intake capacity from this growing foetus that’s encroaching on the rumen,” he says.

“We might have poor winter forage quality, we’ve got growing foetal demands for energy, cold weather that’s increasing maintenance energy requirement — and we actually have a reduced metabolic efficiency in our dry cows as well.

“So it costs more dry matter to actually put condition on the cows.”

That makes the period before dry-off the better window to act. For herds running light, Butler says buying in high-energy concentrate feed at this point is one of the highest return on investment periods for supplementary feeding.

He says how cows are dried off matters too, as conventional methods, including feed and water restriction, can cause a sharp drop in BCS post-dry-off and raise mastitis risk. The better approach is to manipulate protein levels in the diet a couple of weeks before dry-off.

“What we really want to do is gradually dry cows off, by actually manipulating the protein levels in the diet a couple weeks before to really wind the cows down without reducing body condition score.”

Mineral and trace element management through winter is another area Butler says is often ‘undercooked’. Dry cows moved onto crops can face phosphorus deficiencies, copper bound up by iron ingestion in wet conditions and increased metabolic stress.

“Magnesium obviously is a really big one.

“Cows need a really robust magnesium supply to actually mobilise calcium to avoid milk fever, and magnesium can be in short supply in winter conditions.”

Crop-specific molasses blocks are becoming more popular as a lower-labour option for delivering those minerals, Butler says. For fodder beet or brassica crops, he says to find a block specific to that crop to balance the deficiencies.

The rumen itself requires preparation before calving. During the dry period, the rumen papillae degenerate, resulting in a shrinking microbial population that reduces the cow’s ability to ferment feed.

“We can start actually firing that rumen back up prior to calving using the right feeds, fermentable carbohydrates… to the point where those cows actually get onto their milking cow diet earlier.

“Dry matter intakes increase earlier, which is important when you’re feeding things like lime and magnesium through feeds to colostrum cows to avoid milk fever.”

He says it is a case-by-case situation — a SealesWinslow nutrition specialist on farm looking at feed availability, cow condition and farm goals is where the right plan starts.

Get in touch with your local SealesWinslow Nutrition Specialist for tailored on farm support. sealeswinslow.co.nz

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