The quality of feeding in the dry period and early lactation is important in achieving good herd fertility, according to Dr. Joe Patton, a dairy specialist with Teagasc.
Joe said: ”Nutrition plays a vital role in achieving good herd fertility and that the quality of feeding in the dry period and early lactation can affect outcomes.
Therefore many issues cannot be solved by just looking at the diet during the breeding season itself.’
“It remains important to get some key targets right however, such as body condition score (BCS). The target score for cows during the breeding should be 2.75 plus to improve conception rates.”
What can you do if some cows are below target?
Commenting on below target cows, Joe said: ”It will take a couple of months to fix very thin milking cows by feeding 2-3kg extra meal.
”Short-term improvements in conception rate will be minimal. If there are thin or non-cycling cows in the herd that are due for breeding, milking once a day (OAD) for six weeks can boost fertility.”
Joe added: ”High economic breeding index (EBI) cows have been proven to maintain better BCS across a range of diets, explaining in part why their fertility is better.”
Joe recommend that farmers use high EBI bulls to make feeding simpler in the long term.
Dietary requirements for fertility
Energy intake drives milk performance, maintains BCS, and improves fertility. Ensure that the herd is grazing the best quality grass possible (1,400kg covers, three leaf stage).
For herds that are currently grazing Joe recommends that farmers watch residuals (target 4cm) to make sure cows are cleaning paddocks, but not being pinched on intake and ensure supplementation of any deficits of grass in good time.
”High quality pasture contains a high level of crude protein (Nitrogen N) which milking cows use with feed energy to make milk protein,” he said.
Surplus N in the diet may elevate blood and milk urea levels and this may give rise to concerns on fertility.
”Under good management, bulk milk urea does not explain much difference in fertility between herds. Apply fertiliser N small and often during the breeding season; do not overload fertiliser N under drought conditions; and feed high energy 14% crude protein rations at grass to control any risk.
”Trace minerals (copper, cobalt, iodine, selenium, manganese and zinc) can affect fertility, if lacking in the diet. However, feeding these minerals above requirements is expensive and will not boost fertility where no deficiency exists.”
Joe concluded by stating: ”The ‘silver bullet’ of extra minerals will not fix the problems of thin cows, poor heat detection or bad genetics.”