Keep your dairy calves thriving this Summer
At this stage of the year it is time to review the progress of our replacement heifers (or all dairy bred calves) as they are the future of our milking herd. Here Martin Doyle, Teagasc Advisor, Enniscorthy has advice for management at grass, to ensure calf weights stay on track in late summer
Calves once weaned have been at grass since April or May. Meals may have been supplemented to aid performance on grass. Weather was poor and grass growth curtailed. Calves are selective grazers so quality is a priority – covers of 1000 to 1400 kg dm / ha. Caution is also required when grazing the leafy pastures as in recent years some calves grazing very leafy covers have been hit by illness so access to fibre is required – be it some strong stemmy grass or a forage source.
Offer fresh grass regularly
Calves should be offered fresh grass every 3 to 4 days which gives rise to issues:
- The number of calves and the paddock size – need to be flexible
- Grass growth – bursts of strong growth leads to grass becoming too strong for grazing (covers of more than 1400 kg dm / ha. Paddocks need to be skipped for bales
- Fibre needs to be available when grazing very leafy pasture
Weight recording advised
Now with calves settled at grass weight recording should be carried out to establish if the calves are meeting the required growth rate of 0.7 kg / hd / day. Not meeting this target may require meals to be fed to allow for catch up.
At 6 months of age (July / August for early spring born calves) calves should be at 30% of their mature weight
Faecal Egg counts and Dosing
After the quality of the available grass it is the health of the calf that holds back growth rates. Routine dosing was the choice of management but now we are looking to dose as required. The use of faecal egg counts is the go to tool. A faecal egg sample taken in conjunction with your Vet will determine if a dose is required. The weather (damp) and grazing strategy (being asked to clean out paddocks / paddocks grazed annually by young stock) can have a major influence on the parasite burden.
With Veterinary advice if a dose is required then the type of product is important
- Benzimidazoles (white drenches) - no persistency so they will only kill the stomach / lung worms present in the animal on the day
- Levamisoles (yellow drenches) – no persistency so they will only kill the stomach / lung worms present in the animal on the day
- Macrocyclic lactones (clear drenches) – offer a range of persistency
The use of faecal egg counts as a guide to the worm burden will allow calves build up some level of resistance to the worms pre dosing. Over dosing of calves in the first year of grazing can lead to calves being unable to deal with worm challenges in the 2nd grazing year.
Over-use of drugs will lead to resistance to the mode of actions of the different drug types leading to poor health and ill thrift amongst stock. Very few new drugs are being developed for livestock so it is in our interest to mind the drugs that are currently available.
Current advice is not to move dosed stock to fresh clean pasture immediately post treatment. Stock should be returned to existing paddocks. This is to avoid any resistant worms being deposited in fresh clean pasture where they can further develop unchallenged.
If you liked this article you might also like to read Target weights for replacement heifers
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