Fertility is the key to success in the suckler herd and the profitability of your enterprise will depend on every cow producing a calf each year.
Improved fertility performance will have a direct impact on the productivity of your herd. Any factor that prevents a cow from conceiving, carrying a calf to term, delivering a live calf, and rearing it successfully to weaning will have an impact on herd productivity.
Suckler herd productivity improvements will not only increase the profitability of your enterprise but will also reduce carbon emissions and improve environmental outcomes.
To help guide Business Development Group (BDG) farms in this important area of management a series of specialist fertility meetings were developed by CAFRE Adviser Rachel Megarrell and delivered by vets with specialist experience in fertility. These specialist meetings were split into two with Session 1 focused on how to maximise fertility in the suckler cow. This session considered whole herd management, nutrition and animal health issues that affect suckler cow fertility. Use of pelvic measurements as an aid for the selection of suitable heifers for breeding was demonstrated along with the practical steps that are required to achieve heifers calving at 24 months of age. The importance of managing the heifer that calves at 24 months to re-breed again in an acceptable interval was also highlighted as a priority.
The Good Cow
Consider the definition of a ‘good cow’. She should produce a calf for sale every year and achieve a 365-day calving interval. She will calve for the first time at 24 months of age and within your 10–12-week calving season. She will have enough milk and growth potential to drive weaning weight and be easy to maintain, small in stature and produce a weanling 50% of her own weight. It is important to think about Key Performance Indicators (KPI’s) for your suckler herd. As part of session 1 a whole herd fertility assessment was carried out on the host farm and was linked to how they could improve KPI’s for beef fertility.
Each BDG suckler group member receives reports on herd fertility annually. These include:
- Calving interval which is the interval in days for an individual cow between one calving and the next;
- Herd calving index which is the average calving interval of all cows in a herd at any given time expressed in days and;
- Reappearance rate which is a measure of the fertility of a group of cows which have calved within a 12-month period to the start date.
CAFRE Beef and Sheep Adviser Rachel Megarrell urges farmers to examine these reports in detail and look at how many cows are in each traffic light band i.e., green, amber, and red and for any of the cows with a calving interval coloured red (>451 days) identify 1. Any reason for this and 2. Any trend across this group for example if they ran with the same bull.
Correct cow body condition score (BCS) and nutrition are critical during the reproductive and subsequent pregnancy period. BCS is important for calving ease, fertility, and calf performance. Cows will tend to gain condition cheaply at grass and lose it during the winter. Pay attention to thin cows as they are the ones that may experience calving difficulty, poorer colostrum quality, delayed return to oestrus and lower conception rate. If changes need to be made then they should be gradual, one body condition score is equivalent to approximately 13% of the animals liveweight and this cannot be done quickly. Group cows according to their BCS and preferentially graze or feed first calving heifers and thin cows to help them get to target BCS for calving. Ideally a spring calver will calve down at BCS 2.5 and when put to good quality spring grass this will allow them to build condition to achieve a score of 3-3.5 at bulling.
To have a heifer calving down at 24 months of age it is critical to achieve good growth performance especially during her first winter. To bull heifers at 15 months of age they need to be served at a minimum of 60% of their mature bodyweight e.g., a 650kg cow will need to be 390kg at 15 months. To achieve this the heifer over her 15-month growing period needs to attain an average daily liveweight gain (DLWG) of 0.9kg/day. Considerate selection of replacements for the herd is critical and as part of this group members discussed how pelvic measuring can be used to help select heifers that will be more likely to calf unassisted. Vet David McKinstry explained that by using pelvic measurements you can remove heifers with small or bad-shaped pelvises before bulling and therefore breed small pelvises out of your herd. David stressed that you cannot tell pelvic size from the outside and that pelvic measurements are not a guarantee of no problems as calf birth weight will be the biggest factor. Based on this information it is essential that attention is paid to the selection of suitable bulls based on calving ease direct figures and gestation length.
Reducing dystocia (difficult births) will help to have a positive impact on length of return to oestrus. Remember that there is a cost associated with cows not cycling quickly such as the potential revenue from lost calf growth and the cost to feed that empty cow. Difficulties at calving usually come down to poor sire selection, fat cows or abnormal presentations. Refrain from assisting the animal too early but if it is essential gloves should be worn to prevent the introduction of infection and an overall assessment of the situation should be made quickly to determine if veterinary intervention will be required. To have fewer hard calving’s in the herd David advises that you breed replacements from cows that calf themselves. It is also important to complete a pre-breeding check of heifers, ensure that size and weight is appropriate for first calving and pay attention to the pre-calvers diet in terms of energy supply and calcium balance. The cows that will be in the high-risk group for poor fertility performance are thin cows, those that have had twins, a difficult calving or a cesarean section. First or late calvers and any cows with a previous history should be paid special attention.
It is critical that the herd has a comprehensive health plan in place to control infectious diseases that affect fertility. This should be discussed in detail with your vet who can advise the appropriate course of action on an individual herd basis. It should include a vaccination policy for Bovine Viral Diarrhea (BVD) and Leptospirosis as a minimum.
Session 2 of the BDG fertility programme covered ‘Bull assessment and management for fertility’ and was delivered by AI services vet Brian Kennedy. Discussion centered around general bull management including nutrition, handling and assessment of temperament. Brian outlined what a breeding soundness examination should cover and the veterinary issues that can affect bull performance. Your bull should be in ‘fit not fat’ condition prior to running with cows. In an over fat bull, you will see fat deposits in the neck of the scrotum tight to the body wall which will depress semen quality. Overall conformation of the animal is important, pay attention to feet health and mobility of the animal.
Monitoring bull fertility is crucial, Brian advises that you spend time observing and recording services to help detect if there is an issue with the bull. Sub fertility affects 8-18% of bulls, and it is the sub fertile bull that will cause issues within a suckler herd in terms of increased calving spread and calving interval affecting the overall fertility metrics of the herd. If you have concerns over the fertility of your bull, then a pre-breeding check would be important to determine semen quality ahead of the mating season.
In summary when trying to improve herd fertility it is important to take a holistic approach and focus on the areas that are within your control to give your cow the best chance to conceive.
It is planned to roll this two-part suckler fertility programme out across all suckler BDGs in the coming months.
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