As the breeding season continues, the brunt of the work will be getting cows served and in-calf, after which energy intakes for embryo survival will have to come to the fore.
The breeding season can be hard work – consistently monitoring heats, topping up tails paints, synchronising heifers or late calvers, serving cows, and serving repeats can be long and tiresome but very rewarding.
We often look at targets when we talk about the breeding season, such as a 90% three-week submission rate and over a 60% conception rate – all of which can be meaningless if cows are not managed properly after going in-calf.
Teagasc research has shown that nutrition in early pregnancy is critical to prevent embryo loss in dairy cattle, particularly in replacement heifers.
Fewer and fewer cows each year are carrying replacement stock, as farmers opt for sexed semen followed by dairy-beef straws as their breeding plan.
This has decreased replacement rates on farms in the last number of years, as the number of replacements they carry is not enough to produce their desired number of replacement heifers coming through the parlour in two years’ time.
This has led to shortage of dairy heifers across the country and may become a particular issue in two or three year’s time when there is likely to be very few surplus replacement heifers or cows on the market.
This makes it even more important to protect what you already have and what you have already put in calf to save on potentially spending a lot of money on making up your herd’s numbers in two year’s time.
Embryo survival
The trial conducted by Teagasc looked at the effects of short-term changes in energy intake on embryo survival before and after breeding.
The research showed that keeping the diet constant or even increasing the level of nutrition of resulted in high embryo survival rates and that short-term reductions in energy intakes after breeding reduced embryo survival rates in heifers.
This trial highlights the importance of keeping high quality feed in front of cows and heifers and maximise their dry matter intake (DMI).
To maximise the herd’s DMI, make sure cows are grazing pre-grazing covers of 1,400kg DM/ha when the grass plant is at the three leaf stage and full of energy and protein.
Above this threshold, the plant enters into its reproductive stage, where it begins to stem and grow a seed head, decreasing the digestibility and limiting the herd’s DMI.
Ensuring cows and heifers are allocated enough dry matter is crucial, as a 19-20kg of DM should be allocated to a mature herd to ensure they are eating 17-18kg of grass DM.
For heifers, make sure to have plenty of fresh, lush grass ahead of them and keep them moving once a decent residual is achieved, avoiding any pinch in their intakes as you want to avoid placing any stress on the animal in early pregnancy
Avoid causing any stress or any unnecessary disturbance to cows and heifers during the early stages of pregnancy, as that would negatively impact embryo survival. With the grass growth experienced lately, there should be no need to cause such stress.
Another crucial aspect of this is ensuring cows are grazing allocation of 24-36 hours, preferably 36-hour allocation to allow for optimal intakes and for younger, less dominant cows to fulfil their requirements.
Analyse how much meal you are feeding in the cows diet, as high feeding rates will only displace the amount of grass DM the cow intakes, which will then have an impact on the cow’s energy intake.
As we get further into the summer months and good grass growth continues to prevail, ensure the quality of the grass in front of the cows by potentially cutting paddocks that are too heavy for surplus baled silage.
When growth rates are ranging between 60-70kg of DM/ha/day, farmers need to ensure cows are going through their rotation in 20-21 days in order for them to be back again grazing a cover of 1,400kg DM/ha.
