I’m about to start feeding my summer crops, what do I need to remember?

I’m about to start feeding my summer crops, what do I need to remember?
By Katrina Roberts, Herd Health Veterinarian

As with any forage crop underfeeding due to overestimation of intakes is the most common cause of poor performance. Just like 80% of New Zealanders think they are above average drivers; I know you all believe your turnip crop is 12 tonne/ha and your chicory is growing at 120kgDM/day every day! Underestimation of yield (not as much there as you thought) and underestimation of wastage (you think they’ve cleaned up better than they have) both contribute to this situation.

Animals take time to adjust to a new feed in their diet, sure most of the summer forages aren’t as risky to the rumen as Fodder Beet, but you still need some time for the animals to get accustomed to the new routine and feed. Therefore simple steps like;
  • Weaning out the supplement (over 3-5days) you are trying to replace while starting the crop
  • Allowing or budgeting for high residuals or poor utilisation for the first few days
  • Not changing everything at once (e.g. extending the round, starting the crop, removing the minerals all at once is a recipe for poor performance)
You need to take special care of the first lactation animals when you start a forage crop. Be aware of competition i.e. not getting to the face of the crop (long and thin breaks work best to allow every animal access), not acclimatising to the routine, not liking the new feed, not eating as fast as the mature cows and with bulb crops teething is a major issue i.e. will only eat the tops not the bulbs. All of these factors mean that heifers will often lose body condition score while on forage crops, that you will have to put back on in a couple of months’ time.

Animal health issues

Chicory normally doesn’t have too many health issues. However, we have seen nitrate poisoning in chicory when hungry cows grazed a chicory crop heavily infested with the red root weed, and if calves are grazing chicory then bloat is a potential concern if climatic conditions are right.

Photosensitivity (sunburn) can occur on bulb turnips and rape; the risks being stressed crops, rapid transitions, and too much in the diet (high percentage of their total daily intake is brassica).

If you use fodder beet for the lactating cows, I am sure you are aware of the potential animal health risks (acidosis) and mineral deficiencies (low calcium and phosphate). Teaching late lactation cows to eat fodder beet for the first time is extremely challenging, and it is recommended that they have eaten it previously (obviously heifers become an issue here). Training cows and heifers on a paddock of turnips first can work well.

Facial eczema - just because you are grazing a forage crop doesn’t mean you can avoid normal facial eczema prevention strategies, as any amount of grass will have spores in the dead litter over the summer and 3-5kgDM of forage crop does not ‘dilute the spore intake’.

Milk components will often change when grazing a forage crop, but this depends on what you are feeding, your milking frequency and of course composition of the rest of their diet.

Turnips and plantain are ideally fed after morning milking to reduce the risk of milk taint, but also the milk companies recommend you keep these crops to less than 1/3 of the total diet.

Calves do extremely well on either a mixed-pasture sward with chicory or plantain sown into it, or break fed on a crop of these herbs. Chicory or plantain boost the protein and energy content of the diet, which are both often lacking for the spring and autumn R1s when grazed on summer pasture. Ensure you allow (offer) 3.5-4% of body weight (in high quality feed) for the R1s at this time.

If you need any help optimising your summer forage crops from a cow perspective please have a chat to your vet.


Date Added: Thursday, 5th December 2019


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