Autumn breeding within the suckler herd

Date published: 21 October 2022

Many Autumn herds will now be slowing down on calving with the next task in hand being that of the breeding season. No matter whether you are Spring/Summer or Autumn calving, breeding is a critical period for any suckler enterprise. So, what determines reproductive efficiency within the suckler cow?

Herd bull ready for breeding season.


  1. The interval between calving and the return to normal heats
  2. Heat detection efficiency especially where Artificial Insemination (AI) is used
  3. Overall conception rate per service

As seen above, for the breeding season to be a success this Autumn there are many things that must be correct and in order.  These parameters must be monitored to ensure the suckler cow returns to normal heats and so keeping the calving interval of that cow and the overall herd at an acceptable level for your business. 

On average, the time from calving to first heat in suckler cows is 50+ days.  Many factors can influence this time for the better or the worse but ultimately, for everyone we aim to have a cow calving every 365 days where possible.

Body Condition Score (BCS) at calving is one factor which may influence success at calving and a fast return to heat.  Cows at calving need to be fit not fat, as overfat or too thin a cow can in many ways lead to calving difficulties and in response a delayed return to normal heats.  Assess cows according to BCS routinely, aiming to have them in the optimum BCS of 3-3.5 making sure to separate fat cows from thin cows as they will have different feed requirements.  Dependant upon breed and mature weight, 1 BCS could be in the region of 75kgs liveweight.

Mineral feeding to calved cows should remain constant at the rate that they received pre calving, continuing throughout the breeding season.  Depending on the mineral being fed, in most cases 150g/head/day of a quality powdered mineral is suggested according to supplier guidelines.  This will not only have a positive effect on retained placentas and stronger calves but also stronger signs of heat within the cows as well.

Nutrition once calved again is of paramount importance especially where you have 1st calved heifers, older cows or those with multiple births as requirements for maintenance, growth and production of milk will be different for each.  Make sure to have silage analysed.  Silage produced throughout 2022 is of varying quality and autumn calving cows need quality silage.  Aim to feed these cows 70 D Value silage where possible on an adlib basis.  Where this silage quality is not available discuss further with your nutritionist and top up with concentrates on the back of your silage analysis results.  Supplementation depending on silage analysis could be in the region of 1kg to 3kgs/head/day until breeding season has finished to maximise conception rates.

Also, if silage reserves are tight be mindful that feeding 1 kg of concentrate can potentially replace 3-5 of silage depending on quality and overall dry matter percentage (DM%).  Failure to provide a quality diet at this stage could have detrimental effects on not only on the % of cows in calf at scanning but also on calf performance and overall weaning weights.

With reference to heat detection, the concept of restricted suckling for a short period between the dam and the calf twice per day can speed up the onset of heat and decrease the days to service.  If practicing this aim to commence once the cows are approximately 30 days calved and continue for roughly 3 weeks.  This practice can also prove beneficial for later calved cows allowing you to gain back some lost days and tighten up the calving interval.  It is suggested that approximately 85% of these cows will show signs of heat within 2-3 weeks of the 1st separation.  This is due to decreasing the bond between the cow and calf through sight and smell as well as the suckling effect.  In many cases it will also have a positive effect in maintaining BCS while possibly reducing silage intake without having a negative effect on calf performance.

Conception rates in the region of 60-70% are more than possible for suckler cows within both natural service and AI.  This however is all dependent on semen quality, AI technique and bull fertility, so quality control is important.  Aim to have semen tanks topped up regularly with liquid nitrogen and avoid over handling to avoid damage to straws.  Be confident in your AI skills and where you feel you are not capable of the job in hand call in an expert technician to carry out the procedure.  Finally, in the lead up to the calving season, in preparation for breeding, it may be of benefit to ask your local veterinarian to carry out health and semen checks on your herd bull to assess his ability to serve and conceive.

Pregnancy diagnosis can then be carried out effectively from 40 days onwards after last service or insemination, so good record keeping is essential.  This should be something that everyone carries out on farm no matter what period you are calving down in.  It is at this point that you can see whether your efforts to get cows back in calf have been rewarded with a pregnancy.  However, if a pregnancy has not been successful, you can then decide whether other intervention is required such as synchronisation of heat to allow the cow to conceive and stay within her current breeding window with an acceptable calving interval.

In summary:

  • Body Condition Score (BCS) and nutrition are key in determining when a cow will start to show signs of heat post calving with the negative effects of both hard to reverse in some cases. 
  • Be mindful that silage quality needs to be measured if you want to manage feeding it correctly allowing you to target certain quality of silage to different groups of cattle depending on their requirements. 
  • Post breeding and once cows have been diagnosed in calf aim to keep the cows on a settled diet with no major changes to maintain the pregnancy.
  • Artificial Insemination (AI) offers a wide variance of sires allowing you to inseminate your cow to the sire and breed that you feel is best suited with conception rates expected to be 60-70% depending on heat detection efficiency, which you would be aiming to be at >70%.
  • Herd bulls would in most cases have a higher heat detection rate than that of the average stock person in turn catching more heats (target of close to 100%).  However, compactness of both conception and subsequent calving will be determined by the conception rates once the cows are cycling.

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