1. Applied Beef Cattle Breeding and Selection ------------------- Disease resistance in Cattle Larry V. Cundiff ARS-USDA-U.S. Meat Animal Research Center 2008 Beef Cattle Production Management Series-Module V Great Plains Veterinary Education Center University of Nebraska, Clay Center September 19, 2008

2. Mastitis in dairy cattle Heritability =.10 to.20 ( Miller 1982) Attention given to somatic cell count In selection of dairy cattle. Bovine major histocompatability complex (BOLA) genotype has been associated with incidence of mastitis (Solbu et al., 1982) W2 highly resistant to mastitis W16 susceptable to mastitis

3. Infectious bovine keratoconjunctivitis (IBK), pinkeye Heritability =.22 (Snowder et al., 2005) Incidence fluctuates greatly from year to year ( over 20 year period, < 1% to 25% per year, generally < 10%) Incidence can be greater in Herefords than other breeds (Frisch 1975; Webber and Selby, 1981; Snowder et al., 2005) Incidence may be associated with greater homozygosity in Herefords

4. Bovine Respiratory Disease (BRD) (Snowder et al., 2008) Postweaning (18,112 records) - Incidence ranged from 5 to 42% in 14 year period from 1987 to 2001. Heritability =.08 Incidence post weaning (Snowder et al., 2008) Mean incidence by breed (deviation from Angus) Angus 0.00 Hereford4.23 Charolais2.72 Gelbvieh4.09 MARC I1.90 MARC II3.68 MARC III1.08 Differences between breeds were not significant (P >.05)

5. ISheep eryth.Primary 16220 fold.209-11 Pigeon eryth.response IISheep eryth.Primary 13103 fold.212-8 IIISalm. typh.Secondary1690 fold.204-7 IVSalm. typh.Secondary1285 fold.212-4 VBov. Ser. Alb.Heperimmun7310 fold.22 2-4 Rabbit gammaalum precip. globulinantigen Immuni- No. gen. Est. No. Antigens zation to sel. Diff. Herit- independ. Sel. used proc. limit (H/L) ability loci CHARACTERISTICS OF FIVE SELECTION LINES FOR HIGH (H) VERSUS LOW (L) ANTIBODY PRODUCTION IN MICE (Biozzi et al., 1982)

6. SUMMARY OF RESULTS ON RESISTANCE OF HIGH (H) AND LOW (l) MICE TO VARIOUS INFECTIONS (Biozzi et al., 1982) F berghei --++++ Antibody T. Cruzi +++- n.d. - dependentN. dubius --++++ immunity Rabies virus --++++ T Spiralis +++++++ S typohimurium ++++++++ MacrophageT. pestis++++++++ dependentB. abortus suis+++++++++ immunity L tropica++++n.d.n.d. S. mansoni++++++ +++ Degree of resistance Infection Innate resistance Acquired resistance H L H L

7. Conclusions of Biozzi et al. High response lines were more resistant to infections dependent upon antibody immunity. Low lines were more resistant to infections dependent on macrophage immunity. In most cases the line that was spontaneously more resistant also was protected by vaccination to a higher degree.

8. Antibody responsiveness Macrophage activity Severe epidemic infections Severe epidemic infections macrophage dependent immunity antibody dependent immunity All types of mild endemic infections Theory for evolution of host parasite interaction in genetically heterogeneous populations according to inverse polygenic control of antibody production and macrophage activity (Biozzi et al., 1982) H X L cross F 2 hybrids

9. Severe epidemic infections Severe epidemic infections All types of mild endemic infections Under Severe Epidemic Infection dependent on macrophage immunity – Favors AA genotypes, extreme individuals (aa) would be eliminated and heterozygotes (Aa) would also be susceptible to elimination. H X L cross F 2 hybrids All types of mild endemic infections Severe epidemic infections Antibody responsiveness Macrophage activity macrophage dependent Immunity (favors AA genotypes) antibody dependent Immunity (favors aa genotypes) All types of mild endemic infections

10. Severe epidemic infections Severe epidemic infections All types of mild endemic infections Under severe epidemic infection dependent on antibody immunity – Favors aa genotypes, extreme individuals (AA) would be eliminated and heterozygotes (Aa) would also be susceptible to elimination. H X L cross F 2 hybrids All types of mild endemic infections Severe epidemic infections Antibody responsiveness Macrophage activity macrophage dependent Immunity (favors AA genotypes) antibody dependent Immunity (favors aa genotypes) All types of mild endemic infections

11. Antibody responsiveness Macrophage activity Severe epidemic infections Severe epidemic infections macrophage dependent Immunity (favors AA genotypes) antibody dependent Immunity (favors aa genotypes) All types of mild endemic infections Under mild endemic infection – Favors Aa genotypes, extreme individuals (AA or aa) would be eliminated by susceptability to diseases dependent on macrophage (or antibody) immunity. H X L cross F 2 hybrids

12. No Dominance (additive) Complete dominance Partial dominance Over- dominance Effects of different degrees of dominance on phenotypic value

13. Theory of host parasite interaction Theory is consistent with effects of heterosis and benefits of crossbreeding Unfortunately, selection for resistance to a specific disease may lead to resistance for one group of diseases but susceptibility for another group of diseases. Specialized paternal and maternal lines may be best answer. With aid of vaccination procedures in parental seedstock populations and DNA marker assisted selection, It may be possible to select for one type of disease resistance in paternal lines and another type of disease resistance in maternal lines. Then genetic resistance could be realized with vast majority of cattle produced commercially by mating complementary maternal and sire breeds.