On a dairy farm, the time to conception after calving gets a little longer every year. The number of inseminations is rising, some cows show no heat at all and some do not conceive despite three or four inseminations. The vet reviews hormone programmes and insemination timing. These matter, but the problem often starts earlier, in what the cow eats and how much condition she loses in the first weeks after calving.
The cost of days open
The economic weight of fertility is often underestimated, because the loss does not show on any single invoice. As the time to conception after calving grows, the cow spends longer in the low-yield end of her lactation, and the next calving, with the high-yield start of lactation it brings, is delayed. More inseminations, more hormones and more cows culled add to that cost.
Take an example, with illustrative numbers. Assume each day open beyond the target costs about 100 TRY per cow. On a farm with a hundred cows, cutting average days open by 20 days is worth about 200,000 TRY a year. That figure does not include the cost of cows culled for fertility problems and replaced with heifers.
Energy balance
In the first weeks after calving, the cow cannot meet the energy needed for milk from feed and draws on her body reserves. The depth and length of this negative energy balance have a direct effect on when the ovaries start working again. The bigger the energy gap, the later the first ovulation and the poorer the quality of the egg.
So the first step in improving fertility is to raise feed intake after calving as fast as possible. A cow that is in the right condition at calving, gets through the transition period without trouble and eats well after calving closes the energy gap sooner. Cows that lose more than one point of condition in the first month after calving carry the highest risk of fertility problems.
Excess protein
Protein in the ration causes problems not only when it is short but also when it is in excess. Surplus rumen-degradable protein turns into ammonia and then urea. High urea levels in blood and milk can harm the uterine environment and the development of the embryo. On top of that, getting rid of surplus nitrogen costs the body energy and deepens the energy gap.
Milk urea values are a cheap and practical way to follow the protein balance of the ration. A rise in the milk urea results the milk buyer or lab provides regularly shows that the balance between rumen-degradable protein and fermentable energy in the ration has slipped. Correcting that balance improves both fertility and feed cost, because surplus protein is one of the most expensive items in the ration.
Minerals and vitamins
Some minerals and vitamins matter particularly for fertility. Selenium and vitamin E are linked with retained placenta and uterine infections after calving. Copper, zinc and manganese are needed for the health of reproductive hormones and tissues. Beta-carotene and vitamin A support ovarian function too. Forage quality has a marked effect on how much of these is in the ration. In hay stored for a long time, much of the beta-carotene is lost.
But here too, more is not better. Stacking mineral mixes on top of each other can supply some elements in excess, which can upset the absorption of others. Excess molybdenum and sulphur, for example, reduce the use of copper. Working out the ration's total mineral level, including what comes from forages, prevents excess as well as shortage.
Heat stress
On many farms fertility falls clearly in summer. A cow under heat stress eats less, the energy gap deepens, signs of heat weaken and the embryo's chance of survival falls. Shade, sprinklers and good ventilation reduce the effect. On the ration side, it matters to hold energy density while keeping an eye on fibre and rumen health, to feed in the cooler hours and to keep clean water plentiful. Planning the breeding programme with the hot periods in mind improves results as well.
Heifers and first calving
Fertility is also shaped during the heifer's growing period. A heifer that reaches the target weight at breeding age conceives earlier and calves for the first time earlier. Lowering the age at first calving shortens the time the heifer eats feed without giving milk and reduces the herd's total feed cost. But growing a heifer too fast and letting her get fat can harm milk yield and ease of calving in the first lactation. The aim is balanced, monitored growth.
Thinking about the ration together with fertility
OptiFormula TMR calculates separate requirements for fresh, milking, dry and heifer groups with models such as NASEM 2021 and lets you prepare a separate ration for each group. Because forage analyses are kept together with the feed library, the ration's energy, protein and mineral balance is built on real forage values. The ration's nitrogen outputs are calculated as well, which makes it easier to spot surplus protein.
A cow that does not conceive is often the end of a story that started in the ration weeks earlier. Shrinking the energy gap after calving, keeping protein and minerals at the level needed and growing heifers in a balanced way is the route to better fertility that comes before hormones and is usually cheaper.
