Effect of Lameness on Reproduction

Lame cows continue to be among the three main problems we are seeing on our clients farms together with mastitis and infertility. Lame cows are clearly visible but often not treated promptly.

At this time of year with peak milk production and AB well under way, the economic effect of lame cows can be huge due to lost milk production, lost body weight and the fact that lame cows are less likely to cycle on time.

Lame cows are half as likely to conceive and take on average 40 days longer to conception, compared to their healthy herd mates.

If you need help with lameness contact Andrew, Luke or Ryan at The Veterinary Centre.

Milk Urea Nitrogen

Milk Urea Nitrogen (MUN), provides an indication of dietary crude protein status in a herd. MUN is a by-product of microbial protein/nitrogen breakdown in the rumen. Where there is surplus in dietary crude protein, milk urea will rise. A deficiency will result in a fall in MUN. It is generally considered MUN levels above 15-19mg/dL indicate dietary protein is not limiting for milk production. Above 25-30mg/dL there is a surplus (which will load up nitrogen in the urine).

It is considered in herds where there is no deficit in energy but a restriction in protein, cow production may suffer but weight gain can occur. The exception to this rule will be cows that are genetically programmed to make milk ‘at all cost’ (e.g. overseas Holstein type breeds). These cows will mobilise muscle tissue to support milk production which adversely affects reproduction.

Before the introduction of the 190 Nitrogen cap, we sometimes saw these MUN levels drop below 15mg/dL towards the end of the first grazing round, but then sharply increase as cows enter lusher second round grass that had significant urea application.

This season the average MUN figures to date look like they have fallen further again in a lot of farms. This begs the question – are our pastures/soils becoming more nitrogen deficient - it has been a dry winter/spring so significant nitrogen leaching is unlikely? Is this low MUN really limiting production? Do we need to be more strategic with N application in spring? Many farms have removed more expensive protein supplements from cow diets this year – i.e. DDG which may be adding to the picture.

To answer these questions the Vet Centre has partnered with Dr Jim Gibbs at Lincoln University and will be sampling grass on these low MUN farms through the season starting with end of first round grass.

Metrichecking Cows – How to Optimise the Outcome

Endometritis is an infection of the lining of the uterus. Any cow which has an infection in her uterus will suffer a delay in resumption of cycling activity (one cause of non-cycling cows). If infection is still present at the time of insemination then this will interfere with sperm and embryo survival. Long standing uterine infections will also cause permanent uterine scarring. If the surface of the uterus is scarred, implantation and survival of the embryo is impaired.

Trials have shown that cows treated with a Metricure 7-28 days post calving have far better subsequent reproductive results than cows treated 5-8 weeks post – calving. Checking and treating in calving batches will improve results.

Waiting until early October to do a singular whole herd check is an opportunity cost/lost. Uterine infections (although still present), are harder to detect due to the low volume of discharge from the cervix. This leads to a large proportion of uterine infections being missed. Going to the trouble of Metrichecking a whole herd in October and finding just 2% is probably not an economic exercise.

Cows calved by the 25th of August should have been Metrichecked by now. Cows calving 20th Aug – 10th Sept should be checked mid to late Sept, and cows calving after this date in early October. Use a simple identification such as tailpaint to identify early verse later calvers.

• Dirty cows have ~20% higher empty rates than healthy herd mates

• Untreated dirty cows conceive on average 2-3 weeks later.

Top Tips to Minimise Calving Mastitis and lower BMSCC

70-80% of all cows will calve by the end of August, so what you do to control and manage mastitis this month will have a large bearing on the rest of the season. Aim for the BMSCC in the month of August to never exceed 200,000 and average under 150,000.

• Where possible calve springers on the cleanest ground you can. Back fencing springer cows will likely result in more faecal contamination of the udder as cows are forced to sit down in a smaller area.

• Bolster immune defence at calving. Multimin given pre-calving halved the rate of clinical mastitis in a NZ trial.

• Teatspray springers daily if they are coming to the shed – this will both help to condition the teats (make them smooth and soft) and prevent new infection occurring.

• Collect calves twice daily. Studies have shown that the longer the calf stays on the cow, the greater the risk that she gets mastitis.

• Never make springer or colostrums cows run – this may result in blood in the udder and enable bacteria into the teat through leaking milk - cows may also prematurely loose the teat-sealant. Big walks coming back from the run-off close to calving are also a risk.

• Low pressure wash any dirty/muddy teats before the first milking. Dry with paper towels.

• Strip every quarter at the first milking with gloved hands and be fastidious with hand hygiene. Wash hands in between infected cows.

• During the colostrum period hand teatspray before and after cup removal. This will dramatically speed the conditioning of teats. Teatspray concentration should be not less than 1:5 in this period and should have an overall emollient concentration of 15-20%. Apply teat grease to any cows with cracks or chaps.

• On the 4th day in the colostrum mob, RMT test every cow before she exits into the milkers. Treat any clinicals immediately and retain Grade 2 and 3 cows for retesting in 48hrs. Any cows after 48hrs that remain at or increase to Grade 3/clinical should be treated.

• By being the gate keeper and stopping infected cows entering the miking herd you will set the season up for the best quality milk.

• Use anti-inflammatories (Metacam is best) in cows with significant udder swelling (hard, red, painful), in infected quarters. It is the inflammation that causes a quarter to become light. Early anti-inflammatory treatment in conjunction with antibiotics will give the best results.

• Make sure that all staff are fastidious about hygiene before inserting an intramammary into the teat end. The teat end must be cleaned just the same as you would when teat-sealing a cow to ensure no extra bugs are introduced into the udder. Teatspray after insertion.

• Ensure colostrum cows are not overmilked – cups should be on no longer than 9 minutes.

• Monitor your cows’ teats after cup removal – are they excessively swollen, do they feel thick and meaty? This may indicate either an excessive milking time, too high vacuum, a mismatch of inflation to teat size or faulty pulsation.

• Make sure all your staff know the MRS T rules – Mark, Record, Separate and then Treat.

Spring Cow Management

Around 80% of all cow health issues occur inside the first 30 days of lactation. It is therefore imperative that we prepare a cow so her transition from a dry state to a lactating state goes as smoothly as possible.

When this is done well, the result will be reduced risk of milk fever, mastitis, metritis and ketosis. It will also improve dry matter intakes post calving, early milk production and rate of weight loss.

Ideally the springer cow needs the following:

• She should be on a similar diet to her lactating diet for at least 10-14 days before she calves to allow microbial adaption to occur in the rumen.

• If she has achieved BCS 5.0 or better her total ME intake should not exceed 90% of her total springer ME requirements. For a 500kg cow this is about 105MJME down the throat (very important to build in wastage here). A slight energy restriction in these cows results in modest fat mobilisation which in turn primes the liver for its high demands post-calving.

• For cows under BCS 5.0 they should get 100% of there ME requirements (and not more). This is about 120MJME for a BCS 4.0 or 4.5 cow.

• While calculating a ration to provide adequate ME, also provide another 3kg of cereal straw (or similar) as an effective fibre source.

• Springer cows need higher crude protein requirements than cows in the mid-dry period. To have them in a healthy state they need to be on 15-16% crude protein for about 2 weeks before calving. A springer diet heavily based on fodder beet, maize silage or poor-quality silage/bailage is unlikely to achieve this.

• Magnesium supplementation should begin at least 2-3 weeks before calving.

• In some scenarios supplementing with Anionic Transition salts will greatly reduce the risk of milk fever. Gypsum is a safe calcium salt to give pre-caving (100-150g/cow/day).

• Ensure trace mineral status is adequate before calving. Multimin or Selovin 5 should be given 2-4 weeks before calving.