Can breeding help us reach net zero?
Two new genetic indexes to help farmers breed more environmentally friendly cows have been launched in the August bull proofs: Envirocow and Feed Advantage.
Envirocow combines cow lifespan, milk production, fertility and the new Feed Advantage index - this will be expressed on a -3 to +3 scale where the highest positive figures are achieved by the bulls which transmit the best environmental credentials to their daughters. These will become the cows of your future and should create the least green house gas emissions in their lifetimes for each kilogram of solids corrected milk they produce.
Feed Advantage is used as part of the Envirocow index, but is also available stand alone to identify bulls with the best feed conversion to pass on to their daughters; expressed as kilograms of dry matter intake saved for each lactation. In the original study herd there was a 400kg difference in dry matter intake found per lactation between the most efficient cow and the least.
Some of you will be involved in carbon foot-printing on farm as part of your milk contract and you'll know how important herd fertility and age at first calving is to the overall efficiency of your herd - but next time you're choosing bulls have a look at their Envirocow score and Feed Advantage and make sure your chosen bulls are also ticking the genetic box for minimising your carbon foot-print.
Held cleansings - what should we be doing?
Held cleansings or "Retained Fetal Membranes" RFM, happen on all farms to some degree - but what should happen with the placenta? What causes a placenta to become retained? What treatment should we give? Does it affect her future fertility? How many is too many?
Most cows will "cleanse" and pass the placenta within a couple of hours after calving, but if she hasn't passed them after 12 hours it's then termed a "retained fetal membrane" or RFM.
What should happen with the placenta?
The placenta is a complicated organ that grows throughout pregnancy - it is the attachment between the caruncle of the uterus on the maternal side and the cotyledon of the placenta on the calf side - together these two things form the placentome. At every placentome there are little finger like projections connecting the two sides and allowing oxygen and nutrients to pass through to the calf from the dam.
Although oxygen and nutrients can pass between the calf and mum, don't forget that their blood does not mix and so the calf has no maternal immunity in it's blood when it is born - this is why colostrum is SO important in that first few hours of life.
During the normal calving process there is a loosening of the connections in the placenta due to hormone changes both from the calf and the cow, and once the calf is born the blood supply from the calf side stops which causes the blood vessels to collapse and detach. The contractions of the uterus then help to pass out the detached placenta.
What causes RFM?
- induction with steroid
- calving early
- abortion
- twins
- milk fever
- assisted calvings
- caesarean
- vit E / selenium deficiency
- BVD
- immunosuppression
What treatment should we give?
Unfortunately there are very few effective treatment options for a RFM - choices tend to be based on tradition rather than evidence! Studies show pulling the cleansing out has no beneficial effect at all, in fact it increases the risk of metritis, adds 5 days to her restarting bulling activity, 20 days to her conceiving again and decreases conception rates by up to 12%! The cow only has a finite number of carnucles on her side; if we pull at a cleansing that is still firmly attached the caruncle can become damaged and she needs a minimum number to be able to hold in calf in the future.
There is no evidence that putting antibiotics directly into the uterus as a wash out or a pessary helps a cow with a held cleansing either - to release the placenta or to prevent them going dirty - it only helps if she already has a temperature and metritis.
Cows that hold their cleansing are at a much higher risk of becoming dirty and sick with metritis and this does need treating with injectable antibiotics, anti-inflammatories and possibly fluids - but studies show there is no benefit to treating early - "watchful waiting" and a daily temp check is your best bet so you can time treatment to when it is needed.
Injectable oxytocin is often used to help the uterus contract after a difficult calving, caesarean or in a milk fever case - but only a tiny proportion of RFM are due to the uterus not contracting enough - it is much more likely that it is a detachment problem.
Don't forget, oxytocin receptors only last a few hours in the uterus so oxytocin only has an effect at the point of calving.
Does it affect her future fertility?
Yes!
- 5 days longer to start cycling
- 20 days longer until first serve
- 4-10% reduction in conception rate
These are definitely cows to add to your "exclusion" list for not being served to sexed semen - the priority for these cows is a pregnancy, not to produce a replacement heifer - so use either a bull or a beef straw.
How many is too many?
We should be aiming for less than 5% of calvings resulting in a held cleansing - any more than that, or if you are having a spate of them - we need to look at the underlying cause as a priority.
Lungworm: HIGH RISK ALERT
Lungworm risk peaks in September, and the recent warm wet weather has been perfect conditions for rapid development of infective larvae in cow pats.
What to look out for:
- coughing, especially when moved
- milk drop
- neck outstretched
- mouth breathing
- sudden death
DID YOU KNOW?
Pilobolus or "Dung Canon" is a normal fungi found in dung pats that grows to 2-4cm tall. The lungworm larvae crawl up the fungus to the head which then explode spreading the larvae 2 metres from the pat. It is these larvae which contaminate pasture and infect other cattle.
Lungworm is simple to treat if it is caught early enough, but coughing and clincial disease highlights there are holes in the current worming or vaccine strategy which need to be addressed before next grazing season.
COVID-19
Restrictions may have ended, but the virus is still circulating and the Delta variant is incredibly infectious.
Please make sure you continue to let us know if there is anyone on farm with symptoms or if someone has tested positive so we can keep ourselves, our families and the wider community as safe as possible.
Farmers Weekly Survey
Over the last decade, there have been huge changes in the ownership, structure and delivery of farm veterinary practice across the UK. XL Vets has partnered with Farmers Weekly and one of the corporates, VetPartners, to get a balanced snapshot of farmers opinions to those changes, and how they may filter down and affect service at a farm level.
If you have five mins, please click on the link below to have your say:
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