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Spring performance and research findings from the Derrypatrick Herd

06 July 2020
Type Media Article

The Derrypatrick Herd is a suckler beef research herd based at Teagasc Grange. The herd is predominantly Limousin and Simmental crossbreds, with replacement heifers purchased as weanlings the autumn prior to breeding. All heifers and cows are bred to AI with heifers bred to Angus sires and cows bred to a combination of Charolais, Limousin and Simmental sires.

Calving and Breeding Update

Michael McManus, Teagasc Grange

This spring 105 cows calved with 110 live calves, nine sets of twins and four cases of mortality. Average first calving age of heifers in 2020 was 24.1 months of age. Across cows and heifers the calving season for the Derrypatrick Herd in 2020 was just over 11 weeks. The six and nine week calving rates were 84% and 95%, respectively. The level of intervention required at calving was low with 63% calving unassisted, 32% requiring slight assistance and 5% requiring veterinary, with the latter being mostly for malpresentation.

Breeding started on 4th May with 100% of the heifers and 91% of the cows submitted in the first three weeks. Seventy-two per cent of the cows and 58% of the heifers held to their first service. At the time of writing we are in our eighth week of breeding and a breeding scan is due to take place to determine how long the breeding season will last. To aid heat detection all cows and heifers are tail painted every 10 days, and each group has a vasectomised bull which has a chin ball attached.

The yearlings were turned out the last week of March. They were weighed on the 10th June with average live weights and live weight gains since mid-April of 468 kg and 1.25 kg/day for steers, and 440 kg and 1.12 kg/day for heifers. They are currently getting 48 hour allocations of grass and are entering covers of 1400 kg/DM/ha.  Calves were weighed on the 18th June with average live weights of 156 kg for bull calves and 158 kg for heifer calves.

Like much of the eastern part of the country, soil moisture deficits lead to a drastic reduction in grass growth on the farm. With the farm cover falling to 550 kg DM /ha the decision was made to introduce grass silage to the cows with the calves having access to fresh grass in the adjoining paddocks. The replacement heifers and yearling beef animals have remained at grass. With the recent rainfall grass growth rates have returned to normal and grass silage has been removed from the diet.

Genetics Research

Alan Twomey, Teagasc Moorepark

The question often arises whether herds should breed their own replacements or purchase replacement stock. There are many pros and cons to both systems, but one of the perceived drawbacks to breeding your own replacements, is the risk of reducing beef output of the male progeny.

First and foremost, the Replacement Index is designed not only to identify bulls that will breed animals with high merit for maternal traits, like milk and fertility, but also progeny with good beef merit, since at least half the progeny will be for beef production. Therefore 29% of the emphasis of the Replacement Index is based on terminal traits. In other words, it is designed to maintain or improve the beef merit of your herd while improving maternal traits. The current research experiment on the Derrypatrick Herd is comparing the performance of the progeny of sires divergent in maternal traits.

In the Derrypatrick herd, two bull teams have been chosen to compare progeny performance (Table 1). The first bull team were identified from high Replacement Index sires, whilst also ensuring bulls had a high Terminal Index value (i.e. balanced bulls). The second bull team was chosen on the Terminal Index only and so had much lower merit for maternal traits. To ensure a fair breed comparison was carried out, two bulls were selected within the Limousin, Charolais and Simmental breeds for each of the bull teams. For heifers, two Angus sires were used within each bull team.

Table 1

 Balanced TeamTerminal Team
Progeny birth year  2018 2019 2018 2019
Average Replacement index €151 €159 €91 €82
Average Terminal index €129 €133 €132 €129
Bulls used on heifers        
Average Replacement index €145 €138 €96 €119
Average Terminal index €78 €90 €66 €87

Performance to date is very similar between the progeny of the two bull teams (Table 2), although, progeny from the Balanced Team were on average 10kg heavier at weaning compared to progeny from the Terminal Team.  Only progeny from 2018-born animals have been slaughtered to date and results show there is no significant difference in carcass performance between the two groups.

Results from the Derrypatrick Herd show that bulls with a high Replacement Index still have the ability produce progeny with similar output traits to the progeny of bulls selected on Terminal traits only. Advice to herds breeding their own replacements is always select high Replacement Index bulls at breeding. Herds with good fertility and weaning efficiency should aim to use more balanced bulls, bulls which are high on both the Replacement and Terminal index. This will maximise the beef merit of progeny while also retaining heifers with good maternal attributes.

Table 2

 Balanced TeamTerminal Team
2018 and 2019 progeny    
Birth weight (kg) 48 48
Weaning weight  (kg) 313 303
Weanling Value (€) 804 767
2018 progeny    
Age at slaughter (days) 639 646
Carcass weight (kg) 358 352
Conformation (1-15) 8.71 (R+) 8.66 (R+)
Fat (1-15)
8.91 (3+)
8.28 (3=)
KO (%) 56 55

Antimicrobial drug usage in calves on commercial beef and dairy farms in Ireland

Bernie Earley, Teagasc Grange

Antimicrobial resistance is the ability of bacteria (or microbes) to resist the effects of an antibiotic. Antimicrobial resistance (AMR) is one of the leading health concerns in human and veterinary medicine worldwide. AMR occurs when bacteria change in a way that reduces the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. A Teagasc study provides the first detailed information relating to on-farm usage of antimicrobials in suckler beef and artificially-reared dairy calves from birth-to-6 months (mo) of age.  A total of 3,204 suckler beef calves and 5,358 dairy calves were included in the study. On beef farms overall, 12.7%, 5.7%, 2.9% and 20.4% of suckler beef calves were treated with antimicrobials for disease from birth-to-1 month, 1-to-3 months, 3-to-6 months, and birth-to-6 months of age, respectively. The corresponding values on dairy farms overall for calves treated with antimicrobials were 10.2%, 5.3%, 1.9% and 14.8%. The highest risk period for disease in the present study was between birth and 1 month of age, with approximately two-thirds of all disease events occurring during this time period.  The Population Correction Unit (PCU) is a measurement developed by the European Medicines Agency (EMA) and takes into account the animal population as well as the estimated weight of each particular animal at the time of treatment with antimicrobials. A value of 45 mg/PCU is indicated as a global estimation for cattle.

In the present study the mg/PCU was 8.03, 2.70, 1.43 and 7.25 for suckler beef calves for the treatment periods from 0-to-1 month, 1-to-3 months, 3-to-6 months, and from birth-to-6 months of age, respectively. The corresponding values for dairy calves were 9.74, 3.72, 0.95, and 7.11 mg/PCU. The values of mg/PCU in the present study are very low. Disease prevention through proper nutrition, vaccination, adequate housing, and limiting stressors that compromise immunity are likely the most effective means of reducing antimicrobial use.

Actions to take to keep antimicrobials working

  • Only give antimicrobials to animals under veterinary supervision
  • Always give the right dose, and the number of treatments, as prescribed by your vet
  • Do not use antimicrobials for growth ‘promotion’ / disease ‘prevention’ in healthy animals
  • Do not use antimicrobials to treat viral disease
  • Do not use a ‘stronger’ antimicrobial as first-line treatment
  • Vaccinate animals to reduce the need for antimicrobials
  • Improve biosecurity on farms and prevent infections through improved hygiene and animal welfare.

Anthelmintic resistance

Orla Keane, Teagasc Grange

Just as AMR refers to the ability of bacteria to avoid killing by antibiotics, anthelmintic resistance refers to the ability of parasitic worms to survive a dose that should kill them. There are currently only 3 classes of anthelmintics licenced in Ireland for the control of gut worms in cattle. These classes are benzimidazole (commonly known as white wormer), levamisole (commonly known as yellow wormer) and macrocyclic lactones (commonly known as clear wormer). Anthelmintics from different classes have different modes of action. However, within the same class all products share the same mode of action and therefore when resistance develops to one product within a class generally other products in the same class are affected. Recent research from Teagasc has demonstrated that anthelmintic resistance is now common on beef farms in Ireland. Therefore, steps need to be taken by suckler farmers to implement sustainable strategies to manage gut worms and to delay the further development of anthelmintic resistance.

Actions to take to slow the further development of anthelmintic resistance

  • Use grazing management to reduce exposure to worms
  • Use anthelmintics only when necessary
  • Use an appropriate product for the worms being targeted
  • Use the correct dose rates and proper dosing technique
  • Have a biosecurity protocol for bought-in stock

Nutritional management of replacement heifers for optimal reproductive efficiency in the suckler herd

David Kenny and Mark McGee, Teagasc Grange

In Ireland, 75% of replacement beef heifers are sourced from the beef herd, either homebred (60%) or purchased (40%). Teagasc data clearly show that rearing heifers to calve at 36 compared with 24 months of age results in a reduction in net margin per hectare on suckler beef farms of 20-30%. This is mainly a consequence of the feed costs associated with maintaining a cohort of ‘unproductive’ animals within the herd for an additional 12 months.

In addition to its obvious economic importance, work by Teagasc indicates that older age at first calving increases the lifetime emissions burden of the cow and, correspondingly, the emissions per kg of beef produced through production and digestion of feed, as well as manure management related emissions.

Early onset of puberty (by 13-14 months of age) is essential to achieving first calving at 24 months of age. The primary drivers of the timing of sexual maturation in cattle are undoubtedly nutritional management and genetics. In particular, there is now overwhelming evidence to support the importance of early-life nutrition (prior to 8 months of age) in regulating the timing of puberty, with pre-weaning live weight gain having a much larger impact than post-weaning gain. Indeed, recent work conducted at Teagasc Grange shows that offering heifer calves a high plane of nutrition between 4 to 8 months of age doubled the number of heifers eligible for breeding at the start of the breeding season.

Currently, research at Grange is investigating the effect of improved nutrition on the genetic and biological processes involved in sexual development in the young heifer. Optimal nutritional regimens can then be formulated to consistently and cost-effectively ensure that a high proportion of replacement heifers reach puberty before the start of the breeding season, a central tenet of economically and environmentally sustainable, seasonal calving, grass-based production systems.