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13th June, 2021

Optimising Reproductive Performance in Your Dairy Herd

Breeding programmes for spring calving dairy herds should now be the primary focus. The financial implications of missed heats at €250 should focus the mind on the importance of a good heat detection programme.
There are a number of elements which will determine the outcome of your heat detection programme culminating in the desired 90 pc submission rate for compact calving next spring.

In the first instance you need to identify “cows at risk”. These include late calvers, cows which had either twins, milk fever, ketosis, retained after birth, lameness pre or post calving, poor body condition score, calving difficulty or a combination of the above.

These “cows at risk” are less likely to present with normal signs of heat and will have a poorer pregnancy rate to first service. Previous research has shown that almost one third of cows in grass based milk production systems have had an “at risk” experience in either the dry cow or early lactation transition periods.

It makes economic sense to get veterinary attention for these cows. Why wait four to six weeks into your breeding programme to identify these” cows at risk” . Reproductive disorders include anoestrus, deep anoestrus, cystic ovarian disease, uterine infection and physical damage to the reproductive tract.

Leaving these “cows at risk” unattended is analogous to running an engine without oil. You are reducing the survival chances of these cows in the herd. Scan these cows now. You can then make an informed decision on the best treatment regime to get these cows bred as quickly as possible. Make sure you present your late calvers when calved two weeks or greater at this scan. These cows have a limited window of opportunity to establish pregnancy and based on previous reproductive performance are more likely to have reproductive disorders.

The temptation currently pertains to reduce all costs associated with milk production. You cannot afford to address the potential €250 cost of each missed breeding opportunity. Remember that there are many cows in your herd which may even look physically fit, but have a reproductive disorder associated with a previous experience in the dry cow or early lactation transition periods.

Having identified and managed your “cows at risk”, your focus has to be the targeted optimisation of submission rate. In my opinion, the best heat detection aids are a combination of tail paint, teaser bulls with a chin ball marker and time spent by you watching the cows for mild signs of heat.

Any form of stress will reduce the signs of heat and indeed the pregnancy rate from those services. With a late spring, grass supply and quality is restricted on many farms. Stock numbers have increased, but the grazing platform has either remained static or cows have to walk greater distances to graze grass. The stressors associated with group size, grass availability and walking distances will increase the risk of “shy bullers”. Therefore, it is essential that you spend time with your cows watching for cows presenting mild signs of heat.

Keep a close eye on your butterfat to protein ratios and any spikes in milk production. These are indicators of stress in your production system, which will reduce the intensity and duration of standing heats with a consequent negative impact on pregnancy rate.

The breeding programme is a cornerstone of your future business. You have to optimise the fitness of your cows to show heat, have a fertile egg for fertilisation on the day after expression of heat, a uterine environment conducive to the growth of the embryo to produce a signal for pregnancy to the mother between day 11 and 14 after breeding. This is a complex biological web hidden from your daily observation of the herd.

However, you have an opportunity now to optimise the outcome for each breeding opportunity by minimising stressors during this critical period. Grazed grass alone is not a balanced diet for cows in peak milk production while attempting to establish pregnancy. Dietary supplementation with minerals, vitamins, yeast and long chain fatty acids have proven to be beneficial to both the demands of milk production and establishing pregnancy.

The primary cause of poor reproductive performance on many farms is “ocras”. Even with poor milk prices you will exacerbate your financial woos if cows are not gaining body condition score during the breeding programme. Dietary supplementation with concentrates contains the essential supplements for “wellbeing” which are an integral requirement to optimise the opportunity to detect heats and the consequent establishment of pregnancy.

In conclusion identify and manage “cows at risk”, use the ”three” primary aids to heat detection and “supplement diets” to avoid stress and optimise pregnancy rate.
Dr. Dan Ryan is a bovine reproductive physiologist and can be contacted at

Article written by Dr. Dan Ryan for the Farming Independent 3rd May 2016.