During the post-calving period, both inflammation and low blood calcium levels have negative impacts on cow performance and future fertility. So how are these two issues interlinked and what roles do diet and body condition play in helping to manage them?
Inflammation of a cow’s reproductive tract is a natural response post-calving and actively promotes healing. However, if this inflammation doesn’t resolve quickly, a cow will find herself at high risk of clinical and sub-clinical disease.
“We want to see inflammation peaking and then declining rapidly three to seven days post-calving, with the uterus back to its pre-calving state,” explains Dr Bethan Till, Ruminant Specialist at ForFarmers. “If this doesn’t happen, then not only will the uterus risk damage, but the immune system will continue to compete for extra energy – diverting energy away from milk production.”
If farmers fail to manage this post-calving inflammation correctly, not only will they have to deal with the long-term consequences on cow fertility, but also the immediate costs associated with medical issues like metritis and retained cleansings.
“To effectively manage and resolve the inflammation response, the right nutrition is critical, with a focus on supplying a good range of vitamins, high levels of protein and omega 3 fatty acids,” continues Bethan. “However, it’s also important that farmers don’t overlook the role that body condition score (BCS) has on inflammation resolution. Both over-thin and over-fat cows often experience prolonged periods of inflammation after calving, so farmers need to ensure their heifers and cows are at optimal BCS when drying off.”
To understand the link between BCS and inflammation, farmers first need to appreciate the relationship between specific proteins found in a cow’s blood. “Immune cells will produce certain proteins in the blood in response to infection and tissue injury,” explains Bethan.
“One of these is called plasma haptoglobin (Hb), which fuels inflammation. When there’s more Hb in the blood, there is also less albumin in the blood, which – as well as managing good liver function - is a protein that helps resolve inflammation.” Cows going into calving with a BCS above 3.5 will start to mobilise more fat during the post-calving period. This is interpreted internally in the same manner as a physical tissue injury (like muscle damage), stimulating the production of more Hb in the blood, which prolongs and fuels inflammation.
The situation is the same in thin cows, with a BCS below 2.5. It’s therefore crucial that cows are at the optimal BCS as they enter the transition period, with a recommended target of BCS 3 for cows and 3.25 for heifers.
During the calving and post-calving period, cows experience increased demand for calcium to help fuel colostrum and milk production. Managing blood calcium levels of transition cows is a challenge for any farmer but will be exacerbated by poor BCS.
“After calving there’s huge demand for calcium and it needs to be readily available in the blood,” notes Bethan. “If blood calcium levels are too low, calcium will be extracted from a cow’s bones and muscles.
Animals need to be in the best condition leading into and immediately after calving.
“Inflammation will reduce blood calcium levels, so the longer inflammation goes on, the longer it will inhibit the efficient transfer of calcium into the blood stream. This contributes to the likelihood of clinical and sub-clinical milk fever occurring, and can act as the gateway for other metabolic challenges in the future. The consequences are more veterinary interventions, poorer performing animals, and increased culling rates – none of which are good for farm profitability.”
It’s therefore vital that cows and heifers go into the pre-calving period with good levels of blood calcium already in the blood, ready to fuel performance post-calving. “That’s why I recommend dairy producers consider implementing calcium capture or dietary cation-anion balance (DCAB) diets during the pre-calving period.”
At the core of calcium capture is manipulating a cow’s diet to trigger a hormonal response which will make cows release more calcium into their blood. “Translac Advance 28% protein nut contains a binder which actively binds intestinal calcium during the close-up dry period, resulting in decreased blood calcium,” explains Bethan. “This triggers a hormonal response to absorb calcium from the bone, urine and intestines.“
The result is more calcium in the blood, which can immediately be used to help fuel colostrum and milk production. It’s an easy process to manage and can be utilised on a wide range of farming systems. Advance provides a complete diet, is fully mineralised and should be fed at a rate of 3kg/head, per day.”
A full DCAB diet is slightly more difficult to manage and suits systems operating very tight calving blocks – it would not be suitable for flying herds. “The objective of this approach is to manipulate the diet to create low blood pH levels,” explains Bethan. “The lower the blood pH, the increased the muscle tissue responsiveness to parathyroid hormone, which is released in response to low calcium levels. This process ensures that more calcium is reabsorbed from the bones, urine and intestines.
“Trasnlac DCAB and DCAB Zero come in a meal form and it’s important to monitor urine pH to ensure that the diet isn’t taking pH levels too low,” she warns. “A urine pH between 6 and 6.5 is best. Any lower can result in negative consequences for cow health and fertility.”
Both diets offer a viable way to ensure good blood calcium levels post-calving, but getting the right advice to decide which system would work best is essential.
“Animals need to be in the best condition and receiving optimal nutrition leading into and immediately after calving,” says Bethan. Taking advice from a specialist nutritionist will help farmers to fine-tune their transition cow management and diet for optimal results.
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