ICBF have recently launched a new and improved version of the HerdPlus Dairy Sire Advice Application. Sire Advice is an application that is available to all dairy HerdPlus users. This application allows farmers to select the bulls they wish to use for the breeding season and match these bulls to the most suitable cows.
| Old Sire Advice | New Sire Advice |
| Restrictions on breeding levels (max allowed 6.25%) | Remains in place |
| Penalty for inbreeding | Penalty applied has been updated to new economic values |
| Balancing milk and fertility sub-indices of the progeny | Remains in place |
| Balancing milk kgs in the herd | Changed to balancing milk sub-index in the herd |
| Balancing fertility sub-index in the herd | |
| Selection on overall udder and overall feet and legs | |
| Select cows/heifer for cross breeding | |
| Select cows/heifer for beef mating | |
| Select cows/heifer for culling |
Key points on Sire Advice
Sire Advice aims to
- Maximise EBI
- Reduce inbreeding
- More balanced herd
Maximise EBI
To increase herd EBI high EBI bulls need to be selected. Sire Advices bull selector helps identify bulls based on different criteria i.e. overall EBI or based on sub-indices. Other criteria can be used as well i.e. breed, pedigree status, or AI company availability. The bulls selected and their usage in the herd drive the EBI of the progeny produced.
Reduce inbreeding
Similarly to the previous version of sire advice a restriction is applied to the amount of expected inbreeding in the progeny of each mating; this levels remains at 6.25%. In addition to the restriction on inbreeding a penalty is applied to inbreeding between 0 and 6.25%. This penalty is calculated as the economic cost (Table 1), taken from the economic values in the EBI, of the reduction in performance associated with each level of inbreeding.
Table 1. Economic cost associated with 1% inbreeding
| Sub-index | Trait | Economic
weight |
Reduction in
performance |
Inbreeding
Cost (€) |
| Production | Milk | -0.09 | -4.9 | 0.441 |
| Fat | 1.04 | -0.4 | -0.416 | |
| Protein | 6.64 | -0.3 | -1.992 | |
| Fertility | Calving Interval | -12.43 | 0.7 | -8.701 |
| Survival | 12.01 | -0.3 | -3.603 | |
| Calving | Direct Calving Difficulty | -3.52 | ||
| Maternal Calving Difficulty | -1.73 | 0.16 | -0.2768 | |
| Gestation Length | -7.49 | 0 | ||
| Calf Mortality | -2.85 | 0.06 | -0.171 | |
| Beef | Cull Cow Weight | 0.15 | ||
| Carcass Weight | 1.38 | |||
| Carcass Conformation | 10.32 | |||
| Carcass Fat | -11.71 | |||
| Maintenance | Cull Cow Weight | -0.165 | ||
| 0.01 | ||||
| Management | Milking Time | -0.25 | ||
| Milking Temperament | 33.69 | |||
| Health | Lameness | -54.26 | ||
| SCS | -43.49 | 0.01 | -0.4349 | |
| Mastitis | -77.1 | |||
| Total cost (€) of
1% inbreeding |
-15.1537 |
More balanced herd
The pervious version of sire advice aimed to have a more balance herd in regards to the females produced i.e. that the milk kg produced are similar as well as minimising the difference between the milk and fertility sub-indices. The new version has removed the emphasis from reducing the difference in milk kg to the milk sub-index and added in reducing the difference in the fertility sub-index. This aims to produce female that are more similar on both the sub-indices to aid in a more uniform management of the herd. Additionally, there is still emphasis on minimising the difference between the milk and fertility sub-indices.
How mating is allotted?
All mating are ranked in the herd based on
- Progeny EBI
- Progeny Milk SI after accounting for difference for herd average
- Progeny Fertility SI after accounting for difference for herd average
- The difference between Milk and Fertility SI
- Overall udder and overall feet and leg type traits
The suggested mating from sire advice are based on a herd level so that the best combination of mating are used where cows are only been mated once and bulls used up to the maximum usage allowed.
Sire advice produces an index on all potential in the herd and aims to maximise this index in the whole herd. The index is calculated as
Index =
(EBI of calf-15.15*inbreeding of calf)/standard deviation of EBI in active bull list
+
Milk sub-index of calf / standard deviation of milk sub-index in active bull list – difference between milk sub-index of calf and average milk sub-index of all potential progeny/ standard deviation of milk sub-index in the herd
+
Fertility sub-index of calf / standard deviation of fertility sub-index in active bull list – difference between fertility sub-index and average fertility sub-index of all potential progeny/ standard deviation of fertility sub-index in the herd
+
(Overall Udder + Overall feet and legs)/standard deviation of Overall Udder + Overall feet and legs EBI in active bull list
–
Difference between Fertility sub-index and milk sub-index/ standard deviation of difference between Fertility sub-index and milk sub-index in active bull list
All components of the function are divided by the standard deviation of the population of the active bull list to standardise each component and place equal emphasis on each component.
Example of mating allotment
Assuming there was two cows, A and B, to be mated in the herd and two bulls, 1 and 2, were selected to be used equally in the herd, i.e. a bull can only be used on one cow. For simplicity of the example all potential mating will produce offspring with 0% inbreeding and type traits are assumed to be equal.
Calculated average and means values from AI bulls and a sample herd values
| EBI | Milk | Fertility | Milk fertility difference | ||||
| Herd | Average | 145 | 69 | 40 | |||
| Standard deviation | 37 | 29 | 18 | ||||
| Bulls | Average | 24 | 14 | -11 | |||
| Standard deviation | 99 | 33 | 74 | 50 | |||
Information on all potential mating in the herd – Example
| Cows | A | B | ||||||||
| EBI | 190 | 175 | ||||||||
| Milk | 50 | 80 | ||||||||
| Fertility | 90 | 80 | ||||||||
| Bulls | 1 | 2 | 1 | 2 | ||||||
| EBI | 280 | 300 | 280 | 300 | ||||||
| Milk | 115 | 100 | 115 | 100 | ||||||
| Fertility | 115 | 150 | 115 | 150 | ||||||
| Progeny | A1 | A2 | B1 | B2 | Average | |||||
| EBI | 235 | 245 | 227.5 | 237.5 | 236.25 | |||||
| Milk | 82.5 | 75 | 97.5 | 90 | 86.25 | |||||
| Fertility | 102.5 | 120 | 97.5 | 115 | 108.75 | |||||
| difference (Milk SI, Fertility SI) | 20 | 45 | 0 | 25 | ||||||
| Ranking | ||||||||||
| EBI* | 235 | 245 | 227.5 | 237.5 | ||||||
| Sire Advice** | 390 | 372.5 | 400 | 407.5 | ||||||
| Index*** | 5.38 | 4.46 | 5.55 | 5.70 | ||||||
* EBI
** Sire advice index without standardising to population
*** Sire advice index after standardising to population
Based on EBI the best ranked mating is between Cow A and Bull 2 as this will produce the highest EBI calf. By default Cow B will be mated to Bull 1. These mating will produce progeny with an average breeding value of 236.25 with a difference between of 17.50 between the top and bottom calf. However, based on sire advice the highest ranking mating is between Cow B and Bull 2 as this mating produced a calf with a good EBI, minimal difference between milk and fertility and both the milk and fertility sub-indices are closer to the progeny mean. By default Cow A will be mated to Bull 1, which in this situation is also the best ranked mating for that cow. These mating will produce progeny with an average EBI value of 236.25 but with a difference between of 2.50 between the top and bottom calf.
Sire Advice works across the whole herd to produce the best group of progeny based on the cows available the bulls selected and the usage of the bulls in the herd. The resulting mating from Sire Advice will not affect the average EBI of the calves in the herd as this is determined by the bulls selected and the usage in the herd; however, Sire Advice will reduced the difference between the top and bottom progeny.
Credit: Tara Carthy, Teagasc