Still-birth investigation, feeding options and social stressors around the transition period were some of the topics discussed at an SRUC-organised transition cow management event.
Hannah Park reports on the key information covered...
STILL-BIRTH CAUSES AN INVESTIGATION IN THE DAIRY HERD
THE wide ranging implications of still-births should be considered and not ‘pushed down the agenda’.
That was the message from Tim Geraghty of SRUC Veterinary Services who said dairy herd managers needed to examine why still-births were happening.
He said still-birth rate should be calculated and reviewed regularly, and suggested post-mortem investigation when incidence rate for a herd was at more than 2-3 per cent.
He said: “Still-births can be an indicator event of other issues, such as milk fever or infectious placentitis. But as well as the direct financial loss [value of the calf], longer-term there is also the costs incurred as a result of treatment, loss in milk yield and reduced fertility, as well as the loss in potential genetic gain for the herd.”
“In addition to all of this, people who work with stock have a mental health cost to working with dead stock.
“Farmers just do not want to be working in that way when working hard all year to produce a calf.”
On the back of post-mortems he has carried out, Mr Geraghty explained that, on average, two-thirds of still-born calves were perfectly healthy when the cow entered stage two labour (when the feet come into the birth cannel).
“One-third already had an issue, such as iodine deficiency, genetic defect or infectious disease, which would cause the calf to be born dead regardless of any action taken.”
To reduce cases, he advised farmers should focus on ‘modifiable’ risk factors, such as those which could be controlled by an individual rather than circumstance.
Although a practice he said may be more applicable to larger units, Mr Geraghty also encouraged conversations around intervention policy with the farm vet so that all staff, relief included, were on the same page when it came to timings around when to assist with a calving.
“Studies have shown that 75 per cent of cows which are going to calve themselves will do so within 1.5 hours.
“Some suggested timescales include going in to assist if two feet are not be visible in two hours, with additional help in the form of a vet or senior stockperson called after 15 minutes, to factor in waiting time for another party to arrive,” said Mr Geraghty.
“These are all farm specific, but the kinds of conversations which are valuable to herd health.”
■ Sire: Select for calving ease
■ Heifer age: At calving
■ Group changes: Moving a cow when it is in stage one labour can increase the risk of still-birth because it slows the calving down. If a move to a calving or fresh pen is required, do it when the cow is in stage two labour
■ Management: Cows can experience social stressors depending on management style during the transition
■ Nutrition: Feed management and feed space can impact rumen fill
■ Calving technique: There is a high value in having reliable, experienced staff on-hand when it comes to the technique of calving the cow
Non modifiable risks
■ First calving
■ Genetic defect
■ Infectious disease or iodine deficiency
FEEDING THE TRANSITION COW – IS IT WORKING?
VARIOUS options when it came to feeding the transition cow were also discussed at the event, where Lorna MacPherson, of SAC Consulting, highlighted the importance of body condition score (BCS) alongside various nutritional strategies for milk fever prevention.
Ms MacPherson explained the key to a successful calving and transition was getting BCS right at drying off and ensuring cows were getting the right nutrition during the dry period.
She added that condition scoring cows at drying off and again at calving would provide an indicator as to whether cows were losing or gaining weight during the dry period, so that nutrition could be adjusted accordingly.
She said: “The target to dry cows off is a BCS of 2.5-3 which should be maintained until calving.
“There is evidence to suggest over-conditioned cows do not eat as much, leading to lower dry matter intakes and a risk of milk fever.
“They are also more likely to have lower appetites postcalving and lose more weight in early lactation.”
Ms MacPherson said herds should be targeting less than 5 per cent when it came to cases of clinical mastitis, and even when incidence levels were low, sub-clinical cases could exist and manifest as other problems such as retained placenta, metritis or mastitis post-calving.
She outlined several dietary approaches to feeding the dry cow for milk fever prevention (boxed out), but also reiterated the importance of being cautious not to under-feed protein.
“About 70 per cent of foetal growth takes place in the last 60-70 days of gestation, so under-feeding opens-up a host of other problems such as retained placenta, metritis, poorer colostrum quality, less milk and poorer fertility.”
Nutritional strategy approaches
Low calcium: The low calcium approach works by kick-starting the cow’s hormonal mechanism to release calcium from bones to keep blood calcium levels normal.
The goal is to feed no more than 30-50g of calcium per day, with high magnesium supplementation (up to 0.5 per cent dry matter) in conjunction with low potassium forages which are crucial for it to work.
It is typical to have high and also variable levels of calcium in grass silage, meaning achieving a low calcium approach can be difficult to achieve if feeding fresh grass or grass silage in the ration.
Dietary Cation-Anion Balance (DCAB) strategy: DCAB refers to the balance of positively charged potassium and sodium ions in relation to negatively charged sulphur and chloride ions – a partial or full DCAB system can be adopted.
This system makes the blood more acidic and the cow responds to this by releasing calcium from the bones.
This calcium is countering the acidity and acting as a buffer but essentially this is raising blood calcium levels to prevent incidence of milk fever.
Low potassium forages are required for this system to work, either wholecrop or maize silage being preferable to grass silage.
A full DCAB system is recommended during the last three weeks of the dry period, and this involves feeding higher levels of anionic salts.
Remember to beware of palatability and intakes because anionic salts can be bitter and can significantly reduce intakes at a time when we are wanting to maximise rumen fill.
It is essential to monitor urine pH regularly (target 5.5-6.5) to ensure the level of acidity is sufficient but not too acidic. Accurate forage analysis for mineral content is also essential for the DCAB system to work.
Calcium binders: More of these products have become available over last few years, with Nutritional strategy approaches several available on the market.
Essentially, these products will bind calcium in the gut to prevent it from being absorbed into the bloodstream, which causes the cows’ own hormonal mechanism to release calcium from bones.
The type of forage and mineral content is less important on this system, but it is still recommended that energy requirements are met and energy is not overfed in combination.