What does effective dry cow management mean on farm?

Author: Mark Moloney and Sarah Maher

Last year saw many farmers heading into the winter with silage stocks depleted. This meant that feeding silage only to dry cows was not possible in most cases. Bought-in silages, maize silage, wholecrop, straw and meal got a lot of people through the winter. This forced a change in mindset when it came to dry cow management and diet formulation.

In a lot of cases, due to an increase in supplementation throughout the year, cows were dried off in better condition than normal, meaning they needed a maintenance diet for the dry period. If these bought-in forages were analysed for minerals and balanced for energy and protein to support maintenance requirements, cows calved down quite well, with no issues. If not, then there were some metabolic disorders that would be associated with increased body condition, or in simple terms, fat cows. These issues were mainly due to cows being dried off in a body condition score of more than 3.5.

The dry period is fundamental in laying the foundations for the cow to milk to her potential over the lactation. To ensure the dry period is successful, we look at four essential pillars:

1. Body condition score.

2. Management.

3. Nutrition.

4. Minerals.

Body Condition Score (BCS)

The BCS of cows at the different stages of the lactation cycle needs to be monitored and is the most important of the four pillars. The scale of 1–5 is used — 1 being skin and bone and 5 being over-fat. The three most critical stages to monitor BCS are at drying off (BCS 3), calving (BCS 3–3.25) and breeding (minimum of BCS 2.75). If 90% of the herd is within this range at each stage, there should be few issues at calving and high conception rates at breeding.

While the three most critical stages are outlined above, body condition should be monitored throughout the lactation and any significant issues identified at 200–250 days in milk should be dealt with from that stage (late lactation) and not in the dry period.

There are different issues associated with high and low BCS at calving. High BCS can have a negative effect on NEFA (non-esterified fatty acid) levels, BHB (beta-hydroxybutyrate) concentration and blood calcium levels.

NEFA levels are a good measure of negative energy balance post calving leading to metabolic disorders such as ketosis. Studies have shown that the ideal condition post-calving (BCS 3.25) produced less NEFA compared to fatter cows (BCS 4). This meant that cows in ideal condition lost less weight post calving. Further research shows that these cows will have a longer interval from calving to first service and depressed peak milk yield

On the opposite side, cows in low BCS (less than 2.5) are less likely to go back in-calf, milk yield is reduced and more inclined toward lameness.

Management

At farm-level, management can be an issue when implementing a correct dry cow system. Seasonal calving and compact calving are ideal, but not without flaws. In a spring calving system, the blueprint is to have 90% of the herd calving in six weeks. The herd goes completely dry around Christmas week and are all going to get around 60 days dry. This does not happen in most cases, with the average six-week calving at 68%. If the herd is all dried off together, then there will be some cows getting up to 100 days dry. These are the cows which will become over-conditioned and have issues when calving.

Best practice should always be followed where possible and always bear in mind that changes made in the dry period can have a knock-on effect throughout the lactation. Group changes can have a negative impact on dry matter intake. Dry cows should be moved to the calving box no closer than 14 days pre-calving (where possible, as this would require a large amount of space, due to the compact calving system). If movement is required immediately, then pre-calving as late as possible (water bag, feet showing) is the correct procedure.

Dry cows need one cubicle/cow and one feed space and 90% of a stocking rate three weeks pre-calving. A feed space would be considered at around two feet per cow, so 100 dry cows would need 200 feet of feed space. This often seems to be an oversight on farms when deciding how many cows they can house.

Clean water should always be available for dry cows. A rough guideline of five centimetres of trough length should be available. Cleaning troughs is essential, as faecal matter will build up. This should be done weekly.

If cows are at grass then, preferably, they are housed for a month pre-calving and are stocked at 25 cows/ha and given a dry cow diet including minerals. There should be very little grass on this paddock and dry cows should not be used to clean up after milkers.

Management of dry cow feed is important. Pit face and forages used should be monitored carefully for moulds. Moulds can cause many issues in dry cows that might not come to the surface until post-calving, such as abortions or metritis. Mouldy silage should not be fed, and if there is a suspicion of mould, a mycotoxin binder, such as Mycosorb A+®, should be used.

Where there are no feed troughs, feed should be pushed in four to five times per day. Weekly cleaning of feed troughs is required, as feed will build up and become mouldy, which will depress intakes. If feeding a TMR to dry cows feed troughs does not guarantee intakes, there can often be sorting which is not observed. If feeding for two days, heating can occur.

Nutrition

Feeding the dry cow is fundamental to InTouch Nutrition, and there is on-going research and many different ways of implementing a dry cow diet, all of which should have the same outcome: The cow calves down by herself with no metabolic issues and reaches her peak yield, maintains this and goes back in-calf as quickly as possible.

The InTouch Dry Cow system is a controlled energy high fibre diet (CEHF). It is a simple system that provides a single TMR diet throughout the dry cow period. The use of a controlled energy dry cow diet is beneficial for peripartum health, DMI and productivity.

To put this into practice, the BCS of the herd is determined, as is her maintenance energy requirement, based on the silage analysis, which is 100MJ or 8.6UFL. DMI should be set and monitored at around 11 kilograms DM and under 12 kilograms DM for Large Holstein herds with adequate protein levels. For further information, contact InTouch. We can advise on best practice and can even monitor DMI.

There has been a lot of silage made this year, and while the temptation is to feed silage only, this will have a detrimental impact on BCS and DMI. Intake will not be controlled, as a dry cow can eat 13–15 kilograms DM from silage alone. Silages are good in general this year, so feeding a 70 DMD silage for 60 days could give more than 130MJ of energy per day. This will result in a high BCS at calving, mentioned above.

To control intakes and dilute quality of silages while maintaining rumen, fill straw is used. This can vary between 2.5–5 kilograms, depending on forage quality. Straw will also help to dilute the potassium, which is common at over 2% in Irish forages. Straw has returned to normal prices this year, so availability should not be an issue. This straw should be chopped from four to five centimetres and care should be taken when processing. Over-processing will promote intakes and under-processing will promote rejection of the ration, sorting and suboptimal intakes.

It is also recommended to include a small amount of protein in the form of soya. This promotes good rumen function, meaning the dungs are not excessively stiff. Studies have also shown that an increase in the protein content of the diet will increase the quality of colostrum. Some form of concentrate is also desired to allow the rumen bacteria to adapt quickly to consume high amounts post-calving.

Survey results from 277 farms and 24,470 cows showed that implementing this diet correctly led to a 60% reduction in metabolic events, such as milk fever, afterbirths and displacements (Colman et al, 2011).

Minerals

Minerals are often overlooked in a dry cow diet in terms of quality and quantity. It’s important to note that the mineral status of our forages can vary significantly. A mineral analysis is the only accurate way to know the mineral status of your forage to allow you to make an informed choice of an appropriate mineral supplement. Mineral labels can be difficult to interpret, and farmers may not be fully aware of what minerals are being supplied. To ensure the cow is getting what she needs, ask your supplier what the daily mineral supply is, as well as what form the minerals are in. 

On many farms throughout the country, producers are using minerals containing inorganic salts of trace minerals, such as sodium selenite and copper sulphate. However, this form of trace mineral is not what the animal has evolved to use. The soil contains inorganic minerals, which are then taken up by the plant (e.g. grass) and converted to organic forms of minerals. The animal then eats the plant containing minerals in this organic form. Inorganic minerals cannot be stored by the animal and, therefore, do not allow mineral reserves to be built up for times of stress, such as calving or disease. Feeding trace minerals in their organic form such as Bioplex copper and zinc and Sel-Plex, an organic form of selenium from Alltech, lead to these minerals being absorbed at higher levels, stored and utilised by the animal. This helps to build the cow’s immune system and offers her greater protection from metabolic diseases during stressful times and helps improves overall cow performance, such as supporting udder health and reproductive function (Figure 1).

Feeding Bioplex and Selplex minerals has also shown to reduce age at calving for first-lactation heifers by 26 days, who’s dams were fed these minerals during the dry cow period compared to dam’s fed a control (Figure 2).