Hybrid dairy cattle and systems for maximizing hybrid advantage
Systems for selecting, generating, and breeding hybrid dairy cattle are described, as are methods for maintaining herds of hybrid cattle.
1. A method of maintaining an F1 hybrid crossbreed herd of dairy cattle comprising steps of:
implanting an F1 hybrid crossbreed embryo into each of a plurality of F1 female dairy cattle, wherein each of the F1 female dairy cattle resulted from a first F1-selected crossbreed cross, wherein an F1-selected cross is one that involves fertilization of an F0 female gamete with an F0 male gamete, wherein the F0 male and female gametes are from different breeds; and
one or both of the F0 male and female gametes is from an F0 individual or line selected based on one or more improved performance characteristics of prior F1 progeny generated in crosses of the same individual or line;
wherein each implanted F1 hybrid crossbreed embryo results from a second F1-selected crossbreed cross.
2. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes male F0 gametes from the same individual utilized in the first F1-selected crossbreed cross.
3. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes a male gamete from an individual or line different from that utilized in the first F1-selected crossbreed cross.
4. The method of claim 3 , wherein the different individual is selected based on improved performance of its F1 progeny relative to those of the corresponding F0 individual used in the first F1-progeny selected crossbreed cross.
5. The method of claim 4 , further comprising steps of:
assaying one or more performance characteristics of a plurality of F1 individuals resulting from a plurality of crosses that utilize F0 gametes from one or both of the F0 individuals or lines utilized in the first F1-selected crossbreed cross;
comparing the assayed one or more performance characteristics with those of F1 individuals resulting from a plurality of crosses that utilize F0 gametes from the different F0 individual or line; and
selecting a different individual or line for a breeding stock individual or line.
6. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes male F0 gametes and female F0 gametes from the same individuals utilized in the first F1-selected crossbreed cross.
7. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes male F0 gametes from the same line utilized in the first F1-selected crossbreed cross.
8. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes female F0 gametes from the same line utilized in the first F1-selected crossbreed cross.
9. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes female F0 gametes from the same individual utilized in the first FI-selected crossbreed cross.
10. The method of claim 1 , wherein the second F1-selected crossbreed cross utilizes female gametes from an individual or line different from that utilized in the first F1-selected crossbreed cross.
11. The method of claim 3 , wherein the different line is selected based on improved performance of its F1 progeny relative to those of the corresponding F0 line used in the first F1 progeny selected crossbreed cross.
12. The method of claim 1 , further comprising preparing said hybrid crossbreed embryo by in vitro fertilization and culture.
13. The method of claim 1 , further comprising preparing said hybrid crossbreed embryo by in vivo fertilization and collection.
14. The method of claim 1 , wherein said implanted hybrid crossbreed embryo is a previously frozen embryo.
15. The method of claim 1 , wherein said F1 hybrid cross-breed embryo is a cross-breed embryo selected from the group consisting of a Holstein/Norwegian Red hybrid, a Holstein/Jersey hybrid, a Jersey/Norwegian Red hybrid, a Friesian/Danish Red hybrid, a Brown Swiss/Ayrshire hybrid, a Guernsey/Ayrshire hybrid, a Milking Shorthorn/Ayrshire hybrid, a Brown Swiss/Guernsey hybrid, a Guernsey/Milking Shorthorn hybrid, and a Milking Shorthorn/Brown Swiss hybrid.
16. The method of claim 1 , wherein said F1 hybrid cross-breed embryo is an embryo of a Brahman F0 parent.
17. The method of claim 1 , wherein said performance characteristics comprise: milk production, longevity, semen production, age at first calving, body depth, cell counts, cow conception rate, dairy form, daughter calving ease, daughter pregnancy rate, daughter still birth, fat pounds, fat percent, feet and legs score, fertility, final score, foot angle, fore udder attachment, front teat placement, heifer conception rate, ketosis, lameness rate and/or degree, locomotion, milk productive life, milking speed, protein percent, protein pounds, rear legs rear view, rear legs side view, rear teat placement, rear udder height, reproductive life, resistance to cold, resistance to disease, rump angle, rump width, somatic cell score, sire calving ease, sire still bilih, size, stature, strength, teat length, udder cleft, udder conformation, and udder depth.
18. The method of claim 1 , wherein the F0 female gamete or the F0 male gamete is of a dairy cattle breed selected from the group consisting of Holstein, Friesian, Norwegian Red, Danish Red, Brown Swiss, Guernsey, Ayrshire, Jersey, Red & White, Milking Shorthorn, Lineback, Dutch Belted, Burlina, Belarus Red, Canadienne, Carora, Danish Jersey, Frankeston Red, German Black Pied, Brahman, Illawarra, and Meuse-Rhine-Issel.
19. The method of claim 1 , wherein the performance characteristic for selection is not shared by F0 individuals.
20. The method of claim 1 , wherein the performance characteristic for selection is superior in F1 as compared with both F0 parents or F0 lines.