# Presentation: 695350

## Comparison of occurrence and yields of daughters of progeny-test and proven bulls in artificial insemination and natural-service bulls(abstr. 1298)

*H.D. Norman,******** R.L. Powell,** **and J.S. Wright *
- Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350

## INTRODUCTION

- Genetic comparison of natural-service (NS), progeny-test (PT), and AI-proven bulls available at the same time depends partly on selection intensity.
- Previous studies have indicated that PT bulls had superior genetic merit to AI-proven bulls for yield, but that advantage may be decreasing.
- Knowledge of current genetic merit expected from the use of PT, AI-proven, and NS bulls would benefit producers in making economic decisions.

## OBJECTIVES

- Characterize AI contribution to US Holstein population across time.
- Compare genetic merit of PT, AI-proven, and NS bulls available at the same time.

## DATA

- Holstein sire PTA and cow yield deviations for milk, fat, and protein available from USDA national dairy database for breedings since 1959.
- Only first-parity records usable for genetic evaluations included.
- Records grouped by AI status of cow's sire:
- AI proven, major AI organization.
- AI proven, minor AI organization.
- PT, major AI organization.
- PT, minor AI organization.
- NS proven, AI marketed.
- NS only.

## DEFINITIONS

- AI organizations:
- Major: Located in US and has a National Association of Animal Breeders (NAAB) controller number between 1 and 222.
- Minor: Markets but does not process semen.
- AI status:
- PT: Daughters born 8-42 mo after bull entered AI.
- AI-proven: Daughters born >42 mo after bull entered AI.
- NS-proven: Daughters born >8 mo after bull entered AI; bull age 30 mo at AI entry.

## RESULTS

- Percentage of US Holstein cows by AI status of sire and year of first calving:

## RESULTS (cont.)

- Mean sire PTA (kg) for US Holstein cows that first calved during 1998 by AI status of sire:

|  | Sire PTA |  |  |
| --- | --- | --- | --- |
| AI status of sire | Milk | Fat | Protein |
| AI proven, major AI | 348 | 9 | 9 |
| AI proven, minor AI | 185 | 6 | 6 |
| PT, major AI | 220 | 10 | 9 |
| PT, minor AI | 142 | 8 | 6 |
| NS proven, AI marketed | 79 | 8 | 6 |
| NS only | -20 | 0 | 0 |

## RESULTS (cont.)

| Trait | Milk | Fat | Protein |
| --- | --- | --- | --- |
| 1988 |  |  |  |
| AI proven, major AI | 390 | 12 | 9 |
| AI proven, minor AI | 106 | 4 | 2 |
| PT, major AI | 276 | 12 | 6 |
| PT, minor AI | 188 | 5 | 4 |
| NS proven, AI marketed | 166 | 6 | 2 |

- RESULTS *(cont.)*

- Superiority for yield deviation (kg) of US Holstein cows by AI status of sire relative to daughters of NS bulls:

## RESULTS (cont.)

| Trait | Milk | Fat | Protein |
| --- | --- | --- | --- |
| 1998 |  |  |  |
| AI proven, major AI | 441 | 11 | 11 |
| AI proven, minor AI | 242 | 7 | 8 |
| PT, major AI | 242 | 11 | 8 |
| PT, minor AI | 158 | 6 | 6 |
| NS proven, AI marketed | 182 | 6 | 8 |

- RESULTS *(cont.)*

- Superiority for yield deviation (kg) of US Holstein cows by AI status of sire relative to daughters of NS bulls:
- 	*(cont.)*

## CONCLUSIONS

- Percentage of cows sired by AI-proven bulls from major AI organizations was relatively constant (64% for 1988, 63% for 1998).
- Percentage of cows sired by AI-proven bulls from minor AI organizations increased (2 to 12%).
- Percentage of cows sired by PT bulls increased (10 to 17%).
- Percentage of cows sired by NS-proven bulls marketed through AI decreased (15 to 2%).
- Percentage of cows sired by NS bulls  decreased (9 to 6%).

## CONCLUSIONS (cont.)

- AI-proven Holstein bulls from major AI organizations were genetically superior for milk yield:
- 128 to 206 kg compared with PT bulls.
- 368 kg compared with NS bulls.
- 	and nearly equal or superior for fat and protein:
- -1 to 3 kg compared with PT bulls.
- 9 kg compared with NS bulls.
- First-parity daughters of NS Holstein bulls were inferior for milk, fat, and protein yields compared with first-parity daughters of other Holstein bulls during 1988 and 1998.

## CONCLUSIONS (cont.)

- First-parity daughters of AI-proven Holstein bulls from major AI organizations outproduced first-parity daughters of NS Holstein bulls in 1998 by:
- 441 kg of milk.
- 11 kg of fat.
- 11 kg protein.
- Results represent only first-parity US Holstein records usable for genetic evaluations and may not characterize the entire US dairy population.
- More extensive use of AI could increase annual income of US dairy producers by approximately $96/cow.