Downer Cows

Every dairy farm will experience some metabolic downer cow cases this spring and most are a relatively quick fix with metabolic treatment and up within a few hours.

But a significant number stay down for long periods. Any cow which has been down for over 24 hours requires good nursing to ensure a full recovery but this can be very labour intensive and time consuming.

It is important to understand that these cows are often not down due to the primary condition (i.e. milk fever) but are down due to secondary complications such as muscle injuries, nerve damage and compartment syndrome. This damage can occur within as little as 3 to 6 hours of going down, especially if the surface is hard and/or the animal is heavy. So, a cow needs to be got back on her feet quickly or managed appropriately to prevent this secondary damage.

Nursing of a downer cow should only be undertaken if the cow has a reasonable chance of recovery and a competent person is on hand, who is prepared to invest the time and energy in the care of the cow. This is an important animal welfare message. If you are unable or unwilling to provide a high level of care then euthanasia should be elected early in the piece.

Inadequate care of down cows is one of the most common animal welfare complaints from members of the public.

Research has shown that over 45% of downer cows can recover with good nursing, while 0% of cows will recover if very poor nursing is given!

• Ideally the down cow is sheltered and on clean, dry and soft bedding. Normally this means putting her in a calf shed. While the majority of down cows are nursed in the paddock, this is not ideal and she should at least have a cow cover put on her.

• Clean water and good feed should always be available. A cow should drink 40 litres a day and have at least 12-15kg of DM. A 1 litre bottle of Calstart or Headstart is equivalent to a kg DM.

• Longer acting anti-inflammatories such as Metacam and Rimadyl will definitely improve cow comfort and prognosis.

• Move the cow from side to side every 3 hours to ensure her weight is not always to one side and flex and extend the hind limbs each time the cow is moved

• Regularly milk the udder out by hand stripping, check she is not developing mastitis.

• Encourage the cow to rise, use hip clamps to get her to her feet only, never leave cows hanging in hip clamps.

• Regularly re-assess her progress and diagnosis. If you have any doubts ask for help.

Preventing Metritis and Endometritis

Last year we saw a number of herds with a high incidence of health alerts picked up in cows during the first 14 days post-calving. This coincided with high rates of metritis and endometritis in these herds. Once we see these alerts kicking off it may be hard to prevent the problem in cows that are already within 10 days of calving (springers). Five common causes are :

1) Cows calving down too fat – these mobilise high levels of NEFA suppressing the immune system

2) Cows calving down too skinny – these are also immune compromised due to energy status

3) Cows having inadequate dietary protein in the final 3-4 weeks of pregnancy – protein is required for production of antibodies and this may be preferentially drawn on by the calf when in short supply

4) Clinical or sub-clinical milk fever – slows the involution of the uterus 5) Selenium deficiency – reduces the immune function and increases the chances of retained membranes.

Optimal dietary protein intakes are regularly compromised in the last weeks of pregnancy when cows remain on Fodder Beet crops with low leaf yield together with low protein supplements. Ensuring that the springer diet is meeting the energetic needs and no more is also vital.

If metritis and endometritis has been a problem in the past – discuss transition cow prevention steps with your prime vet.

Balancing the Winter Diet

Fodder Beet

A cow in the dry period typically requires 10-11% dietary crude protein as a minimum to remain healthy and gain muscle mass as well as body fat. This requirement (for udder development, colostrum production, rapid phase calf growth) starts to rapidly increase in the final 3 weeks of gestation reaching an optimal 16% in the final 10 days before calving. Fodder beet (FB) is usually low to marginal in protein. The leaf yield of the crop is a prime determinant in the total available crude protein. Crops that have low leaf yield or have had minimal nitrogen application/depleted soils will generally be low. Careful consideration needs to me made around the form of supplements to complement a FB diet. Where the CP levels are low, addition of a good quality grass or lucerne silage/bailage will aid in restoring to optimal levels, whereas a poor-quality hay or straw will worsen the situation. Getting crops tested for crude protein is a good place to start when calculating supplement balance.

Fodder beet may be low in Phosphate (but not always) and is commonly low in Calcium. Phosphate levels in beet in the Waitaki area are not as low as those reportedly found in other areas in Canterbury. With Calcium the leaf typically contains 5-7 times the concentration than the bulb. Thus, having a healthy leaf yield is a good way to ensure cows are not deprived. Testing for these two macro-minerals is a good start point to decide on the requirement for supplementation. Lucerne is a good matching supplement for FB as it is generally high in protein and very high in calcium.

Where is it is possible to provide calcium on FB I suggest you do it. 50g/day of DCP plus an additional 50g/day of limeflour will meet most requirements. Some crops are quite low in salt. Mixing salt with limeflour/DCP can encourage intakes. Most Fodder beet ‘loose lick’ type products benefit from an additional calcium boost.

Selenium levels are always very low, so ensure cows are well supplemented while on crop or going on and coming off. High rates of soil ingestion can deplete liver copper stores so keep this in mind particularly with R1s and R2’s.

Kale/Giant Rape

Generally, kale will have adequate crude protein to support pregnancy - ~15% crude protein, but this is not always the case if it has been nitrogen deprived (it can measure sub 10%). Most of our brassicas are high in Calcium so require no additional supplementation – they can be quite good at replenishing bone stores.

Kale however contains goitrogens which can bind up dietary iodine. Consider supplementing with iodine, particularly with R2’s as deficient heifers are more prone to still births.

Kale diets usually result in the body consuming more Selenium and Vitamin E (vitamin E deficiency is also associated with still births and RFMs). For Vitamin E restoration try to get back onto 5kgDM plus of grass 10 plus days before calving and ensure selenium supplementation pre and post going on the crop.

It is recommended that a maximum of 75% of the diet be kale, the rest silage/hay.

Nitrate Poisoning

Nitrate poisoning is due to a buildup of the compound in plants that cattle are grazing or accidental fertilizer ingestion. The nitrate ion in the plant becomes nitrite in the rumen, enters the blood stream and combines with red blood cells. This causes non oxygen carrying methemoglobin to form instead of hemoglobin. Cows are particularly vulnerable.

Clinical signs can occur within an hour of exposure to the toxic feed and include:

• Salivation and frothing

• Diarrhoea

• Abdominal pain (especially if fertilizer is the cause)

• Laboured breathing

• Staggered walking

• Body tremors

• Blue/grey gums

• Coma and death

Nitrate poisoning cases usually involve multiple animals. The treatment is methylene blue dissolved in saline given intravenously, which replaces methemoglobin with hemoglobin and if given quickly enough will save the animals life. While waiting for your vet to arrive, all animals that seem unaffected should be moved away from the toxic feed and monitored closely.

Eye fluid and blood from deceased animals can be tested for nitrate levels, and the blood usually has a characteristic chocolate brown colour.

Plants use nitrates for growth as a protein source, this process requires energy from photosynthesis. Nitrates build up in plants during periods where photosynthesis is limited such as during prolonged foggy weather, low temperatures and during frosts.

When rain breaks a drought, plants rapidly pick up nitrates and commonly become toxic.

The most affected feeds are annual rye-grasses, some new pastures, oats, kale, rape and brassicas. Suspect feeds can be tested either at your local Veterinary Centre clinic or test kits can be purchased for use on farm. The test turnaround time is approximately 40 minutes and only requires two handfuls of the feed. Toxic feeds should be retested at weekly intervals until safe to feed.

Risk can be managed by feeding suspect pastures or crops in the afternoon during winter, and filling cows up on hay before changing breaks.

Fodder Beet Feeding in Late Lactation

Feeding up to 5-6kg of Fodder Beet (FB) in late lactation has multiple benefits.

• It allows the round to be extended, with a relatively cheap supplement.

• Is very good for encouraging condition gain.

• Cows are partially transitioned before heading off farm for the winter.

Providing that there is still a significant quality grass portion in the diet (9 kg plus), it is unlikely that at 5-6kg/DM of FB that cows will be protein deprived. However, at 5-6kg of FB in the diet, a lactating cow still producing 1.7kg of MS will be in a negative balance for Calcium. She will be drawing on bone stores and have a higher chance of clinical milk fever. Calcium supplementation (~150g lime-flour cow/day) is important to maintain health and production, and reduce bone calcium exhaustion before the next lactation.

One problem that we repeatedly see with FB transition is the creation of space for cows to get onto the crop. Creating a headland in the crop by using a Beet bucket and feeding this in the paddock initially works very well. Once on a crop, a herd needs 1 linear metre/cow on the face and 6 square metres (minimum) of room/cow on the headland.

Cows should start on an allocation of not more than 1-2kg/cow/day. Maintain this for 3 days until all cows are eating and then increase by 1kg every second day. Cows are best to go onto the crop hungry to encourage shy eaters.

Using an ‘increasing time allocation technique’ and using a big, long break (6-7m2/cow) to enter a paddock can be risky. Those that use it usually start with 15 minutes (precisely!) and increase the time by 5 minutes every 3 days. Once a long headland is established (fully eaten), then move to using accurate measured daily allocations. Use a stop-watch and wait with the cows!

When setting an allocation, it is easiest to calculate if the fence is shifted parallel to the rows. Cows will graze 12-18 inches under the wire so will effectively always be eating the next row.

Train the cows to stay and eat their allocation. Even if most is eaten in 20 minutes, cows should stay on the break for 2-3 hours so they all learn that they need to eat.

Never allow beet to build up in a break. You have over allocated and need to pull back. Day 7-10 on crop is where problems often occur when cows will suddenly click and eat the accumulated surplus.

You must accurately measure your crop yield to enable accurate per cow allocation!