About 20% of the Marshall herd has been dried off in advance of calving starting in early September. Cows are selectively dried off based on calving date. The policy for dry cow antibiotics is to set a somatic cell count (SCC) threshold of 150,000 cells/ml and if a milk recording result is below this for the last three recordings, the cow only receives a teat sealant.
If SCC is above 150,000 cells/ml in any of the previous three milk recordings, she will get an antibiotic and a teat sealant. Dry cows are out grazing, some on ground away from the farmyard and some behind the milking herd. All have access to dry cow mineral lick buckets and are dosed at drying off.
They also will get scour vaccines at between six and three weeks prior to calving. When a reasonable number are dry, around 30 to 40 cows, a hoof trimmer will be brought in to do their feet. The cows are calving down to either dairy or beef, using a combination of sexed and conventional semen.
Dry cows will be managed as two groups – ‘Far off’ and ‘Close up’ groups. Far off (eight weeks from calving) will remain at grass while the Close up (approximately four weeks before calving) group will be housed and offered second-cut silage plus 2kg of a precalver nut. In-calf/spring-calving heifers will also join this Close up group approximately four weeks before calving.
All the calving pens and calf house have been powerwashed/steamwashed in preparation for calving. Cows will be calved, milked using a mobile milking unit and calves fed colostrum. Calves will then go to the calf house, be fed on a teat bucket and monitored to ensure they are sucking correctly before being moved to the automatic calf feeder. This usually happens when the calves are around seven to 10 days old. Calves are also vaccinated for pneumonia.
This year, there will be an automatic calf feeder in every pen in the relatively new calf house, as recently an additional automatic calf feeder was purchased. Consequently, when a calf is in that pen, it will remain there until weaning. This should reduce the risk of spreading disease through the calves.
Richard Marshall has control to increase/decrease the milk fed to calves to ensure they are achieving calf performance, mainly targeting daily liveweight gain greater than 0.8kg/day. The aim is to hit 100kg by day 100.
Current yield in the milking cows is 21l on 3.5kg concentrate and freshly-grazed grass, no buffer feeding, out day and night. Cows are being offered grass with pre-grazing total cover of 3,000kg DM/ha (1,500kg available) and they are grazing down to 1,800 (300kg) DM/ha.
As cows are dried off, the stocking rate pressure drops, allowing cover to build and grazing round to increase. Currently, one bag/ac of 27% straight nitrogen is being applied after each grazing. Only one field was sprayed for docks on the grazing platform. Graze- out is good, so little or no topping has been completed.
Second-cut silage was ensiled last week, with third cut planned for late August after slurry and 2.5 bags/ac of 24-0-13 have been applied.
Weigh to potentially reduce costs by £44,000
Benchmarking figures collected from Northern Ireland dairy farms shows that the average cost of rearing a replacement heifer from birth to calving is approximately £1,900. However, more importantly, the range varies from £1,500 to £2,600 per heifer.
This means that for those farmers, it costs £2,600 (€3,050) per heifer and assuming the performance (weight and size at calving) is the same and that on average each farmer has 40 heifers, there is £44,000 (€51,600) of a difference in total cost between those farmers hitting targets and costing £1,500 (€1,760) per heifer to rear and those hitting performance targets but costing £2,600 (€3,050) per heifer.
Batch calving in autumn or spring helps manage these costs and aids efficiency. Calves can be reared in groups to hit targets at regular intervals and managed in terms of additional feed and health treatments, which makes the job easier.
The basics are simple – get calf rearing right to weaning, get weight gain at grass right and then try to get as much grass as possible into calves before they are bred at 15 months of age at 60% of mature weight. Doing this as cost effectively as possible means getting lots of high-quality grazed grass into heifers. Visit ifj.ie/webinar to see the short webinar with Dairylink farm adviser Aidan Cushnahan, where he outlines how Dairylink farmers are managing heifer rearing and why weight recording is absolutely crucial to knowing where heifers are for their age and what feed they need.