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Matt Ryan

Management Hints

April 2023


  • Set yourself breeding season targets for April
  • Know the financial cost of not meeting targets
  • Methodically follow a sequence of breeding decisions from April 1
  • Maximise submission rates to overcome poor conception rates
  • Use the six-day synchronisation programme with heifers
  • Every serious-minded dairy farmer should use all sexed semen this year
  • High grazing stocking rate in April-May are key to grassland management


  • Cows
    • Three-week submission rate: 90% of the herd
      (national average = 71%).
    • Repeat intervals (1-17 days) 10% or less (serious issue on some farms).
    • Normal intervals (18-24 days) heat returns: 70%.
    • Prolonged intervals (24 days) and greater heat returns: 20% and lower.
    • Non return rate (NRR) to first service: 70% (national average = 58%).
    • Calving to service interval: 60 days or less.
  • Heifers
    • Three-week submission rate: 100% of heifers (national average = 80%).
    • NRR: 80-85% (national average = 75%).
    • AI one week before main herd.
    • Nationally and individually among ‘very good farmers’ we are a long way off these targets. What are your fertility figures for 2022, and calvings in 2023?
    • How can we make these targets happen? See below.


  • The following losses accrue
    • Six weeks calving rate: For every 1% below target you lose €8.22/cow.
    • Calving interval: For every one day lost, you lose 0.12c/L.
    • Replacement rate: For every 1% over 18% you lose 0.14c/L.
    • Days in milk: For every 30 days short of target, you lose 0.6 c/l.
    • Herd age (lactations): Every one lactation below target 4.5 = loss 1.5c/L.
  • The six-week target and herd age, more or less, embrace all other losses listed.
  • 100-cow farmers on average are losing over €28,000 by not achieving these targets.
    • A serious loss, mainly due to: 
      • National six-week calving rate being 66%.
      • Calving interval is 388 days.
      • National culling rate is 21% (target 18% B&W and 14% Jx).
      • National age of herd being 3.6 lactations (target 4.5+).      
  • As well as the financial losses, farmers are now appreciating the convenience of compact calving from a labour and time-management point of view.


  • Decide on your mating start date (MSD) based on your targeted median calving date for 2024 and the number of days from start of calving to median calving date in 2023.
  • Based on research, the following median calving dates are advised: 
    • South (dry land): February 16 (50% herd in calf by May 9).
    • North (or wet land): February 26 (50% herd in calf by May 20).
  • The target number of days from start of calving to median calving date is 15-20 days for cows and 10 for heifers:
    • The median calving date is that day when 50% (half) of the cows have calved.
    • Look up yours on the calving report on the ICBF site for your herd for 2023.
    • Then, subtract your days from the target median calving date in 2023, to help you decide on the start of mating date.
  • It is best to start recording heats three to four weeks before MSD – early April.
    • This will give you information to identify non-cycling cows.
    • Non-cycling cows may be due to low BCS, lack of iodine, cows that have retained afterbirth, had milk fever, had a left displaced abomasum, etc. – get vet to check them.
    • The following programme is recommended for non-cycling cows or late calvers that calve 35+ days:
      • Day 0 (am): Insert PRID or CIDR and inject GnRH.
      • Day 7 (am): Inject PG and remove the PRID/CIDR.
      • Day 9 (pm): Inject GnRH (56 hrs post PG).
      • Day 10 (am to noon): AI all cows (16-20 hours post GnRH).
      • Of course, you must plan all this with your vet.
  • Decide on the number of dairy AI straws required:
    • For every replacement you need 4.5 conventional straws and 2.4 sexed semen straws (see March Management Hints)
    • In a 100-cow non-expanding herd with 20 R2s (bulling heifers) and using conventional straws, you will require 20 easy-calving straws for the R2s, 70 straws for the cows, and beef straws for the remainder.
    • Late-calving cows, calved less than 30 days before MSD, and genetically not good enough, will complicate this; therefore, use 95 dairy AI straws over four weeks.
    • For larger herds, extrapolate this process to fit the number of cows,
  • A lot of time must be spent in identifying the very best cows and the best bulls to suit your farm.
  • Identifying your best cows: The R2s will have the best genetics.
    • Your best cows will have EBI €160+, fertility €80+, % fat 0.15+ and % protein 0.10+, with positive on health traits and yielding above average kg milk solids (MS) on the milk recording.
  • Identify our ‘ideal’ black and white AI bulls, who must be high EBI, with fertility over €120, with a maintenance of over €20, with PDs for % fat and protein of 0.27 and 0.20, respectively, with a health figure of €7+ or as near as possible to these criteria. I have a list made out with 40 bulls meeting the ‘ideal’ requirement. 
  • Metricheck all cows 20-28 days after calving to make sure no infection is present.
  • Body condition score (BCS) loss, 0.5+ score, from calving to MSD results in 20% lower conception rates; therefore, BCS the whole herd now and early May:
    • Any cow that has lost weight should now be put on once-a-day (OAD) milking so as to be on a rising plane of nutrition for the two weeks before and after mating.
    • Cows under BCS 2.75 should also go on OAD milking.
    • Cows must be on a rising plane of nutrition now with no decrease in energy intakes post-mating – see Table 1 for meal feeding levels for various levels of grass intakes to achieve various levels of milk yields.

Table 1: Level of meal (kg) required to maintain BCS depending on milk yield and grass intakes.

Gras intake (kg DM)

20kg milk

22kg milk

24kg milk

26kg milk

28kg milk

30kg milk


















































  • This plan will help you achieve the three-week 90% submission target.
    • As an alternative to the aforementioned treatments and where the six-week calving rate is poor on a farm, I recommend the 'why wait programme'.
    • This involves moving cows being served in week two to week one, and from week three to week two, but you need very good pre-mating records.
    • See Table 2 for the date/procedures which must be followed to the letter of the law.
    • You must accurately identify and record cows coming on heat during the last 21 days before MSD – mark them with a special colour or marking, as per Table 2 suggestions.
      • That means for a MSD of May 1, pre-mating heat recording must start on April 5-7 with all calved cows painted red.
      • Cows identified as being on heat in weeks one, two, and three are painted yellow, blue, and green, respectively, leaving the red ones to be seen by the vet. 
  • Be alert to volume and % protein decreases as these are indicators of energy deficits in the cows' diet. It may be due to:
    • Poorer grass quality.
    • Lower intakes due to wet weather or very low covers in dry weather.
    • A lot of bulling activity. 
    • Health issues.
  • Good grass can support 20+ litres/cow/day.
    • Make sure to back-check cows' intakes per day during breeding. 
  • Establish your annual yield by multiplying the peak yield by 215-225;
    • Over-feeding may put you into the high stocking rate band.
  • Mineral issues: If you suspect problems in this area, blood test 10% of your cows, get a composite grass analysis from four to five of the first paddocks being grazed in the second round,
    • A farmer targeting a median calving date of February 20, 2024, should follow this plan:
      April 20 (-10 days); tail paint all cows red and record heats as they occur;
    • April 23 (-7days): MSD for heifers. Put on scratch card and serve for next six days;
    • April 29 (-2 days): PG all heifers not served. AI as they show heat;
    • April 30 (-1 day): Paint blue, all cows that have shown heat;
    • May 1 (0 day): Mating start day (MSD) for cows;
    • May 11 (+11 days): Vet examines all non-cycling cows (red paint).   
  • On the May 7 (or seven days after MSD), cows with yellow paint should get 2cc PG.
  • To move week-two expected heats to week one, all cows with blue paint should get 2cc PG on the MSD.
    • They will come bulling two to four days later (cows rarely come on heat the day after PG).
    • With this programme you will have AI-ed 60% of your cows within seven days and 90% within 14 days of MSD.
    • Many of my clients have successfully done this over the last few years, with very good calving results subsequently.
  • As you will see from Table 2, I am recommending an early scan, 32-39 days post service. It is done only once per week as outlined, scanning cows that have not been served a second time/ are supposed to be pregnant.
    • Whether you do ‘why wait’ or not this early scanning option is very worthwhile, instead of waiting until 30 days after the end of breeding season, which only confirms pregnancy.
    • So, you are confirming pregnancies, achieving early identification of cows you have missed days 18-24, and a good scanner will identify ‘weak’ pregnancies.
    • From this you could PG non-pregnant cows and re-serve again in a few days.

Due to their biological position, heifers take six to seven days longer to go back in calf the second year; hence, the need to calve the heifers six to seven days before the cows.


  • High submission rate, target 90% in three weeks, is the key to deliver the 90% six-week calving rate.
  • Heat detection is difficult as the following facts show:
    • Each standing mount only lasts two to three seconds.
    • The average number of mounts by Holstein-Friesians and heifers is 11.
    • Bulling lasts three to 30 hours, averaging 11 hours.
    • So, you only have a window of 25-40 seconds to see some cows on standing heat.
  • If you miss her, you have lost €140-€180.

Table 2: ‘Why wait programme’ for May 1 MSD* or any MSD*  MSD = Mating start date


Heat in
the period
pre-MSD (*)

Colour paint on cows back

Expected period

post MSD* (days)

PG date to achieve 2 to 1, and 3 to 2

Colour paint


period post MSD        



The recommended weekly scan day will be this day post MSD*

Actual scan date for a May 1 MSD*


-21 to -14 days


0 to 7 days



32 to 39 days


+39 days

June 8


- 14 to - 7days


7 to14 days

May 1 or MSD


32 to 39 days


+ 39 days

(week two to week
one cows)

June 8


- 7 to 0 days


14 to 21 days

May 7 or MSD +7 days 


39 to 46 days


+46 days

(week 3 to week 2 cows)

June 15

  • What heat detection aids are available?
    • Tail paint with non drip household emulsion at a cost of 20-25c/cow for the season. But be careful to keep strip only two inches wide.
      • Clip hair prior to ‘painting’ as paint will come off easier and layering will be minimised.
    • Specialised tail paints with brush on bottle costing €1/cow for the season.
    • Aerosol sprays, costing 30-80c/cow.
    • Kamars, costing €1.50-€1.80 each.
    • Paint sticks, costing 15c/cow, or so, every time it is put on.
    • Scratch cards, recommended for heifers.
    • Vasectomise bull, but do not use him until five to six weeks into the breeding season as he will be ‘murdered’. You still have time to get the vet to ‘fix up’ an uncastrated yearling. You need one for every 30 expected bulling cows.
    • Computerised systems, but they made need back up with tail paint.
    • Five observations per day, but this is very demanding.
  • To convince you to use paint, the following research data is worth remembering: 
    • If 90-100% of the paint is removed, then there is a 95% chance the cow is bulling.
    • Even if 50% of the paint is removed there is a 70% chance she is bulling.
    • So, you should bull cows when paint is gone.
  • To avoid confusion, it is essential to put on the paint correctly:
    • A nine-inch long and only two-inch-wide strip from the top of tail head forward to the highest point. Simple, but this is key!
    • If it is wider or longer than this, you will be confused if some paint is removed.
    • Use scratch cards for heifers – don’t use paint.
  • When is the best time to AI?
    • The optimum time is 12-24 hours after heat onset. And 14-20 hours for sexed semen.
    • Poorer results arise if served earlier than eight hours or greater than 28 hours. 
  • The AI technician needs a suitable crush to be accurate. The ideal service crush is free standing and 1.75m x 0.71m with a 1.37m chain at the back to hold her in – no steps. 
    • As they will be working on their own this year, have a good communication system for them on the day. With the sire advice the technician will know, in advance, which AI bull goes on which cow.


  • Or you could go to Sire Advice Plus where, effectively, you identify your best cows for mating to the best AI bull; your cows for culling; your cows for beef AI/bull and cows for cross breeding. Farmers with very high cow genetics MUST use this option, even if time-consuming, it will be worth it.
  • Click on Menu > Applications > Sire Advice > Manually enter Bulls > Add (green on right hand side) > add the AI bull that you have previously identified > Straw Allocation > Run Sire Advice > Save > send to AI.
    • I am amazed how few farmers use this wonderful facility.
      • It is more important than ever this year so that the AI technician has a clear message without you being there looking over their shoulder.
    • Use ICBF Sire Advice to match your AI chosen bulls with your cows. Follow these steps:
  • In Table 3, I outline my selected B&W bull list for 2023 – it may be incomplete, but it gives farmers with a preference to B&W bulls an opportunity to choose what I consider to be the ideal or near ideal B&W bull:
    • EBI ranges from €274-€387; fertility ranges from €108-€209; maintenance ranges from €15-€28; kg MS ranges from 17.5-36; PD for % fat ranges from 0.15-0.48; while the PD for % protein ranges from 0.11-0.29.
    • Health, carbon, calving and management also need to be taken into account.

Table 3: My Suggested 2023 B&W AI bull list (incomplete). Source: Various catalogues and active bull list.

Bull code

Bull code

Bull code

  Bull code

Sexed/easy calving

ot easy calving

easy calving

not easy calving








FR 8466





















































Use a stock bull if you wish to reduce profit by €100 per year for every cow in your herd.


  • In relation to the male dairy calf, dairy farmers are very conscious of their responsibilities. One of the ways they can act on this responsibility is to minimise the number of dairy bull calves being born.
    • That is achieved by using sexed semen, which delivers nine heifer calves for every 10 dairy AI calves born.
    • My March Management Hints outlines Stephen Butler’s suggestions for making this new practice a success.
    • Contrary to the past, there are 200,000 sexed semen straws available from the very best AI bulls.
    • As maiden heifers are a major focus, I have listed the easy-calving sexed semen bulls in Table 3 that I consider will add to gain to every B&W herd.
    • Farmers that, for whatever reason, are not ready to adopt sexed semen should consider a ‘contract mating’ agreement with a very high EBI herd as outlined below.


  • Anyone who tells you they don’t do this is telling you they don’t believe research, as this is essential if you want compact calving next year,
    • As a result, 50% of heifers will calve within 10 days and all will calve in February.
  • Everyone is familiar with the seven-day synchronisation programme but as most farmers using sexed semen will be doing FTAI (fixed time AI) I will outline it.
    • FTAI for heifers – planned with your vet who supplies the drugs.
    • Day 0: Insert PRID/CIDR.
    • Day 5: Inject PG.
    • Day 6: Inject PG and remove the PRID/CIDR.
    • Day 8: FTAI, 48 hours after PRID/CIDR removal and inject GnRH
  • This is very successful but R2s must be above target weight, on their third cycle, and on a suitable plane of nutrition (not a bare paddock near the farmyard!)
  • If 30% of the heifers have not been mated on day six, do not proceed with the seven-day synchronisation programme as something is wrong.
  • There are other options – talk to your vet or adviser.
  • It is imperative that you have made your VET and AI technician fully aware of your plans.
  • It is almost certain that in most parts of the country, iodine is deficient or marginal, therefore, put 1cc/hd/day of iodine in the water trough for heifers from April 1-June 1.


  • Aim for the following grazing stocking rates, which will free up the remainder of the farm for silage and you can calculate if those acres delivers enough silage for next winter: 

Animals/hectare                      April-May                            June-July

Cows                                                4.7                                            3.6

Cattle (wt/ha)                             2,500kg                                 2,200kg

Calves/ha                                      22                                             14

  • If these high stocking rates result in grass being tight you can graze some of the silage ground. But you must make this plan because silage ground will get 70 units N/acre whereas if you depend on taking out surpluses off grazing paddocks, they will only get less than 40 units/acre.
  • This plan ensures a large first cut which is the cheapest silage.


  • Short of grass leading into the second rotation.
    • Establish the average farm cover (AFC) by measuring it immediately.
    • You need an AFC of 600-700 in early April with the following AFC per cow:
      • Most of country: 180-200.
      • Wet/cold land: 200-210.

Pre-grazing covers (PGC) of 1,200-1,300 and a PGC of 1,500-1,600 for the start of third rotation.

  • Meal will need to be fed as per Table 1.
      • So as to feed 800-900kg/cow this year, you should not average more than 3kg meal this month but the preferable amount will be 1-2kg per day.
    • 35-45 units of protected urea + S per acre will need to be spread on most farms while good clover swards will need none. Two bags of 18:6:12 will have merit on some farms.
  • Make sure to apply all your slurry now (for a lot lower losses) on your silage ground but not exceeding 3,000 gallons per acre.
    • Use 60-70 units/acre of urea, discounting for slurry N and residual N from grazing.
  • Graze silage ground a second time before closing mid-April. This will alleviate grazing grass shortages and reduce spending by three to four times the cost of grass on meal.
  • Contract mate with a high EBI farmer if you have a low EBI herd and you are worried about selling dairy male calves. 
  • This is a great system and should be adopted because if the high EBI farmers have any sense, they should plan to have the minimum of dairy heifers being born – less than 25% of the cow numbers.
  • What I'm talking about above is a legal agreement whereby the low EBI herd farmer agrees to buy X number of dairy heifer calves next February at an agreed price for an agreed genetic merit animal.
  • In two years’ time you could have €260 + EBI heifers and fertility over €120 capable of giving you 9% fat and protein.
  • The low EBI farmer can put all his cows in-calf to easy calving beef AI bulls – the advantages are obvious.

Did you know?
It takes eight litres of water to produce one litre of milk. 
It takes 158 litres of water to produce one litre of almond milk.