What challenging times we live in right now? There is so much uncertainty out there right now and who knows what we will and won’t be able to do between now and the end of 2020.
When will schools open again, when will we be able to get back to doing normal things such as going to a match?
Unlike the rest of society now, the farming community is functioning almost as normal. Apart from a different way of getting supplies from merchant stores and not being able to visit a mart, not a lot else has changed.
On dairy farms, May is a very busy month, silage is to be made and following that there will be plenty of slurry to go out, the breeding season continues at full speed, while calves will be heading to grass too.
Milking cows in May have a busy time of it too. They are going back in calf and grass quality can be variable as managing it can be a challenge at this time of year.
In our Irish grass-based production system, keeping the right quality and quantity of grass in front of cows is essential. Balancing this grass according to the cow’s potential will ultimately determine her production and fertility performance.
Avoiding grazing heavy covers is as important as avoiding grazing excessively lower covers.
Cows tell us what they think of their diet
Every time cows are milked and the quality of the milk is tested from the bulk tank, the cows are letting us know how well they are being fed.
Milk protein the main guide, along with lactose to the energy status of your herd and there has proven to be a link between milk protein and fertility.
The lower the milk protein the more days between calving and conception.
What influences milk protein content?
Stage of lactation; early declines post calving followed by later lactation increases as volume dilution diminishes.
Underfeeding of energy, especially when forage quality is poor, results in poor dry matter intakes.
Strong grazing swards will depress overall energy intake. These drops in forage intake will also depress butter fats.
Mid-season grazing is much higher in energy than first rotation and late season grass.
Managing this grass and complementing it correctly will enable cows to utilise more of the energy consumed.
Higher volume cows tend to have reduced protein (and fat) percentages (dilution factor)
Converting litres and percentages to total kilograms of milk solids is the best way to compare individual cow performance and individual herd performance.
The energy status of the herd in early lactation has a significant influence on fertility. The larger the loss of condition between calving and first service the less likely you are to have a successful conception.
When cows drops less than 0.5 body condition score then they have circa 65% conception to 1st service. If cows drops between 0.5 and 1 body condition score then their chance of conception decreases circa 53%.
If more than 1 body condition score is lost, then conception to first service is as low as 17%.
Reducing body condition loss post calving
Energy drives milk production, fertility and body condition, while the protein content of the diet has a big bearing on both milk yield and condition. High-protein diets will increase milk yield by driving total intakes of energy.
Too much protein supplied to milkers will have a detrimental effect on cow condition over time as she must mobilise energy reserves to process and excrete the excess protein.
This is very often the case on top quality grazing pastures at this time of year where sward protein contents can be in excess of 25%.
Complementary feeds fed with grass that are high in starch and sugars will help to increase milk solids and maintain better body condition once they are complemented with sufficient fibre to maintain rumen health.
Obviously every effort must be made in the current climate to produce as much milk as possible from grass, but many herds have cows that require additional energy beyond maximum grass intakes and this feed must not induce digestive upsets while aiming to balance the qualities in grass.
When a cow consumes sufficient energy each day post-calving then a negative energy balance (NEB) is less dramatic and therefore fertility improves.
Balancing grass and complementing its feed value
It is very rare that cows are capable of eating more than 19kg of dry matter at grass alone on a consistent basis. Given that a minimum of 19kg of dry matter is required by most Irish cows to maintain milk production then supplementation is often required.
Grazed grass tends to be very high in crude protein mid-season and if this is balanced incorrectly with high protein concentrates then the cow must as I mentioned earlier mobilise body fat reserves in order to get rid of this surplus.
The excretion of this excess urea has a cost of approximately 2.5 litres of milk per day or 12.5 to 15 MJ of energy, which equates to 0.5kg condition loss.
The effective fibre is also often very low in well managed grazed grass, which will be shown by low butter fats particularly in April and May.
Minerals and vitamins also need to be balanced for grass as in most areas of Ireland the ground is deficient in some vital minerals.
Some will also bolus cows pre breeding if they have identified a particular mineral which has a large deficit on the farm. These would include copper, selenium, iodine, cobalt, and zinc in particular.
Complementing top quality pasture- how does it work?
Buffer feeding is the complementing (not replacing) of grass with a mix of concentrates, minerals and or forages in the yard around one or both killings.
Remember that buffer feeding does not always mean feeding forages in the feed passage and can simply be done in the parlour depending on grass availability.
Watch that you don’t feed excessive protein in the parlour. Once we get in to second rotation and beyond then a low protein 12%-14% is sufficient in the parlour when you are typically balancing 22%-26% protein grazed grass.
Most feed mills now supply excellent low protein blends/nuts which help to balance grass very well.
If your milk buyer tests for milk urea then you have an excellent tool at your disposal to assess protein supply and utilisation.
This can help you to make both feed purchasing and nitrogen application decisions on your farm. Where butter fats are struggling access to straw or good quality grass or maize silage can supply the necessary fibre where appropriate.
Dry cow feeding and management and its influence on herd fertility
Obviously there are little or no dry cows remaining on dairy farms, nonetheless it is worth talking about how they were managed this past winter and spring. Managing your dry cows can have a major role in successful fertility on your farm.
The follicle, which is ovulated during the breeding season, began its development in the last few weeks pre calving.
Therefore, the diet the cow is on in the dry period may determine the subsequent quality of the ovulation 12 to 14 weeks later and thus have a major bearing on the chance of fertilisation.
Dry cow diets should provide sufficient energy and protein for maintenance; cows should be dried off in the condition in which you would like to calve them down.
A well-managed dry cow diet will set cows up for a successful lactation and this includes a less troublesome breeding season. Preventing metabolic disorders post calving is a great start to any cow’s lactation.
Calving is stressful enough without going down with ketosis or milk fever soon after when it can be avoided. Avoiding calving complications serves the farmer and well for their future.
Did you do a pre breeding scan?
If so, have you taken action with problem cows?
Have you a list of cows that you have not seen bulling yet, perhaps they should be scanned now to get them back cycling?
Maximising total dry matter intake post calving and leading up to breeding will drive fertility performance.
Grass quality and balancing it well will lift milk protein. It is important to take action if milk protein or butter fats are falling, sooner rather than later.