Section index:
p54-56 Water matters
Quality and quantity important considerations
p58 On-farm testing
Help with diagnostics and treatment
p60-63 Award winners
Focus on animal health leads to sustainability accolade
Section intro:
This animal health special looks at issues around water quality, youngstock health and on-farm bacteriology and features a farm at the top of its game for animal health.
A change in the calving pattern for Dan Millers herd has meant it is even more important than ever to achieve good heifer growth rates and improvements to youngstock health have been key to this.
By working hard to maximise passive immunity and, at the same time, ensuring acquired immunity is boosted, Mr Miller and his team at Cribhouse Farm, Stalbridge, Dorset, have made huge strides in improving calf health.
While levels of calf pneumonia were certainly not at a critical level, there was a real desire to make improvements to calf health in order to reduce antibiotic use in youngstock and also to make sure calves were achieving good growth rates so heifers were well developed when calving into the herd at two years old.
This was particularly important in 2021, as the herd moved from all-year-round calving to autumn calving, a change driven by a desire to make the most of the 36-hectare (90-acre) grazing block.
Mr Miller says the calving period for the 170-cow herd is not intended to be tight with calving taking place over four to five months so milk is produced all year round.
Mr Miller says: While the calving block is relatively long, we do want to the heifers to calve at the beginning of July and August.
In the past, heifers calved into the herd at an average age of 28 months, which Mr Miller says suited the previous system and meant any surplus stock sold well as strong in-calf heifers.
He says: Now we are aiming to calve them slightly earlier, but we still want them to be strong.
With the knowledge that pneumonia has an impact on growth rates, meaning heifers could potentially be underweight at service at 14-15 months, which also has an impact on puberty and conception, a decision was made to focus on disease prevention.
Mr Miller says much of this was driven by herdsman Louis Sarsfield, who worked closely with the farms vets, Lucy Hepworth and Helen Rogers, and nutritionist Charlie King to develop and stick to a plan for youngstock health.
The approach can be split into two areas: maximising passive and innate immunity; and boosting acquired immunity.
The first area relies on following protocols for optimising colostrum quality and calf colostrum intake.
Working with the Mr King, the dry cow diet was formulated with colostrum quality in mind.
Cows are given a scour vaccine at drying off, which helps boost colostrum antibodies for rota/coronavirus and E.coli. Mr Miller says scour incidence has greatly reduced and is now at a minimal level.
Colostrum quality is tested using a Brix refractometer, with colostrum measuring 22% or more fed to calves. The aim is to give them four litres as quickly as possible after birth.
Total proteins are monitored at the start of the calving block to get an idea of passive transfer levels. At the start of the 2022 calving block, results showed that 80% of calves tested had good levels of antibody absorption.
Mrs Hepworth, of Friars Moor Livestock Health, Dorset, says: Practice data for our autumn calved herds in 2022 showed farms ranged between 50% and 100% for calves having good levels of antibody absorption.
She adds that monitoring total proteins at the start of the calving block is a good idea, as it gives farmers the opportunity to make improvements if results are below target.
Calves are fed transition milk for three days before moving onto milk replacer, with the manufacturers guidelines followed for formulation.
Calves are fed four litres of milk twice a day for six weeks. Milk is then gradually stepped down over a three-week period to weaning.
Mrs Hepworth says there is a gap in immunity at about two to four weeks when passive immunity fades and the calf is developing its acquired immune system.
She says: I always encourage clients to feed high levels of milk powder for the first six weeks to provide the immune system with plenty of energy to help support this period.
The second area is boosting acquired immunity with vaccination and calf environment plays a vital role in this to minimise challenge.
Mrs Hepworth says: Last year the heifers were vaccinated with Bovalto Respi 3 at two and five weeks of age and this means there is full vaccine immunity by eight weeks of age. The vaccine gives six months of protection, so comfortably lasts the length of the housed period.
Vet technicians carried out these vaccinations, meaning calves were vaccinated at the correct age with an appropriate gap between doses.
While the vaccine spend at 1,500 in 2022 was not dissimilar to the cost of treating pneumonia the previous year, this does not take into account the impact good youngstock health has further down the line in terms of longevity and milk yields.
As well as vaccination, the team at Cribhouse also aims to minimise stress and challenges during the rearing period by managing the weaning process and avoiding group changes at stressful times, including weaning and disbudding.
Harry Arnold, who is responsible for feeding the calves, says: Calves are kept in individual pens to start with, before moving to groups of five, then groups of 10, where they stay until after weaning.
There are no group or shed changes for at least a month after weaning to keep stress levels to a minimum.
The management of other diseases, particularly coccidiosis post-weaning, is important.
Mrs Hepworth says: Coccidiosis is common in autumn-born calves and we used a therapeutic drench last year to treat this.
Ahead of the next block, the shed will be disinfected for coccidiosis and alterations to feeding troughs are to be made to reduce coccidiosis challenge.
The calf environment is also an important part of disease prevention and Mr Miller says the calf shed was designed with sloping floors to keep moisture away from the calves and is also well-ventilated with a fan and duct system.
The positive impact this approach to youngstock health and pneumonia prevention has had is clearly evident.
Mr Miller says that around Christmas 2021 there was an outbreak of pneumonia, which meant all the heifer calves had to be treated with antibiotics.
He says: Jump forward to autumn/winter 2022/23 and there has been a vast improvement in calf health and calves grew well as a result.
This improvement is also mirrored in vet and medicine costings, with the cost of drugs used to treat pneumonia, including antibiotics and anti-inflammatories, falling by 94% for the period of July to March, when comparing 2021/22 against 2022/23.
51AV视频facts
170 cows giving an average yield of 9,320 litres at 4.5% butterfat and 3.5% protein
Heifers served at 14-15 months to sexed semen
50 replacement heifers a year are kept
Most milk, about 75%, is sold to Barbers for cheesemaking, with the remainder used in products produced on-farm and marketed under the Dorset Dairy Co brand
