Friday, March 29, 2024

Avoid back pocket pain

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Feeding supplements to extend the lactation of cull cows in a low payout year “will only hit farmers in the back pocket”, AbacusBio farm consultant Kevin Wilson of Dunedin says.
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“Culls should be dropped out of the system as soon as they can no longer be sustained by pasture alone.”

He said whether a farm was low- or high-input, feeding supplements always needed to be questioned and should always only be fed during a genuine pasture deficit to improve potential milksolids (MS) response (Table 1), improve body condition score (BCS) or to fill genuine short-term feed gaps.

Milk production response to supplements when residuals were less than 1500kg DM/ha was consistently 6g to 8g MS for every megajoule of metabolisable energy (ME) fed.

“With good quality silage (ME >11) this means you would expect about 75g MS/kg supplement, resulting in a return of $0.38/kg MS at a $5 payout.

“This silage is costing $0.47/kg DM after allowing for 20% wastage (Table 2), which gives a $0.09 loss per kg DM offered and this provides no allowance for the cost of feeding the supplement ($0.05-$0.10/kg DM). In a low payout season it doesn’t stack up feeding supplements to culls.”

Instead, he advocated offloading culls early to maintain pasture covers for those cows which will calve in the next spring.

“There are significant indirect benefits from culling early as this will allow more feed available to put on BCS for the animals which are being retained for the following season,” Wilson said.

“Studies from New Zealand and overseas consistently show that BCS has an important role in influencing cow reproduction, with BCS at calving being the most important BCS measure relating to fertility.

“Also Roche (2007) indicates that milk yield increases linearly with increasing calving BCS (up to BCS 5).

“This would suggest farmers need to focus on improving average BCS during autumn to help meet industry target BCS at calving. Cows calving at less than BCS 5 will also have an extended postpartum anoestrus period, reduced potential number of breeding events, reduced milk production and increased vet and AI costs.

“Therefore, autumn management of your herd will have a strong influence on next year’s seasonal production and fertility.

“By identifying and offloading culls when pasture alone can no longer support intakes in late summer or autumn, you will make this season a more profitable one, as well as the next.”

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