# Presentation: 512598

## CONCLUSIONS

- The increase in frequency of crossbreds will make it even more useful to identify genetic background to monitor the population rather than relying on the reported or evaluation breed of an animal.
- As expected, Holsteins are contributing the most genes, but the impact is less among crossbreds.
- Three-way crosses were infrequent. The tendency was to mate F1s to the sire breed, suggesting breed change more than infusion of outside genes for one generation.
- Non-traditional breeds are having little impact, even among crossbreds.
- These results and interpretations are dependent on the data reported and are impacted by any systemic changes in completeness or accuracy of reporting, including characteristics of the production-tested population.

**Mating sire breed for various F1 crosses**

- Crossbreds represent a different mix of breed background than among purebreds: much less Holstein and more of non-traditional breeds. It is disappointing that so many crossbreds trace to animals with an unknown (actually, unreported) breed.
- The percentage of cows in the national database that are crossbred increased from 0.6 for cows born in 1990 to 1.3 in 2000 and 3.0 in 2005.

**Percentages of genes by breed in females born in different years**

- Holsteins continue as the predominant provider of genes.
- Jersey contribution declined from 1990 to 1995, but increased thereafter.
- Ayrshire, Brown Swiss, and Guernsey contribution has declined.
- Milking Shorthorn contribution has been fairly steady as has the total for remaining breeds while unknown background has increased.

- The most frequent sire breed for crossbreds was Holstein through birth year 2000 and Jersey since then.
- Frequency of Guernsey, Ayrshire, Milking Shorthorn, and non-traditional breed sires generally declined, while Brown Swiss was similar in 1990 and 2005.
- Crossbred sires are rare but sires of unknown breed increased markedly in the late 1990’s.

| Breed | All | Purebred | Crossbred |
| --- | --- | --- | --- |
| Holstein-RW |   90.8 |     92.4 |      37.1 |
| Jersey |     6.3 |       5.9 |      17.8 |
| Brown Swiss |     0.9 |       0.8 |        5.8 |
| Guernsey |     0.3 |       0.3 |        0.7 |
| Ayrshire |     0.4 |       0.3 |        1.6 |
| M. Shorthorn |     0.3 |       0.1 |        5.3 |
| Unknown |     0.9 |       0.0 |      30.3 |
| Non-traditional |     0.1 |       0.1 |        1.3 |

**RESULTS**
**Percentages of population attributed to breeds**
**for females born in 2005**

|  | Birth Year |  |  |  |
| --- | --- | --- | --- | --- |
| Breed | 1990 | 1995 | 2000 | 2005 |
| Holstein-RW | 90.5 | 91.7 | 91.5 | 90.8 |
| Jersey | 5.7 | 5.3 | 5.9 | 6.3 |
| Brown Swiss | 1.3 | 1.1 | 1.0 | 0.9 |
| Guernsey | 1.3 | 0.8 | 0.5 | 0.3 |
| Ayrshire | 0.8 | 0.7 | 0.5 | 0.4 |
| M. Shorthorn | 0.2 | 0.2 | 0.2 | 0.3 |
| Unknown | 0.1 | 0.1 | 0.4 | 0.9 |
| Non-traditional | 0.1 | 0.1 | 0.1 | 0.1 |

|  | Birth Year |  |  |  |
| --- | --- | --- | --- | --- |
| Breed | 1990 | 1995 | 2000 | 2005 |
| Holstein-RW | 48.3 | 39.4 | 21.0 | 22.9 |
| Jersey | 12.6 | 10.0 | 20.9 | 24.6 |
| Brown Swiss | 6.8 | 7.4 | 7.7 | 7.3 |
| Guernsey | 4.1 | 1.6 | 0.8 | 0.7 |
| Ayrshire | 3.1 | 3.8 | 1.7 | 1.0 |
| M. Shorthorn | 13.0 | 16.7 | 11.0 | 5.9 |
| Crossbred | 0.6 | 1.0 | 0.5 | 0.4 |
| Unknown | 7.1 | 16.9 | 34.5 | 35.4 |
| Non-traditional | 4.4 | 3.4 | 1.8 | 1.7 |

**Percentages of sire breeds for crossbred females**

|  |  | Percentages |  |  |
| --- | --- | --- | --- | --- |
| Sire | Dam | Sire Breed | Dam Breed | Third Breed |
| Hol | Jer | 80 | 17 | 3 |
| Jer | Hol | 51 | 43 | 6 |
| Hol | BS | 84 | 13 | 3 |
| BS | Hol | 37 | 56 | 7 |
| Hol | Gue | 90 | 7 | 3 |
| Gue | Hol | 53 | 43 | 4 |
| Hol | Ayr | 91 | 5 | 4 |
| Ayr | Hol | 29 | 62 | 9 |

- About 95% of all first-generation crossbred cows were mated to bulls of one of the crossbred’s parental breeds: sire breed 58%, dam breed 37%.
- Use of a third breed was relatively infrequent, ranging from 3 to 9% (average of 5%).