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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 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 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 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 Hereford Charolais Gelbvieh MARC I MARC II MARC III 0.00 4.23 2.72 4.09 1.90 3.68 1.08 Differences between breeds were not significant (P > .05) CHARACTERISTICS OF FIVE SELECTION LINES FOR HIGH (H) VERSUS LOW (L) ANTIBODY PRODUCTION IN MICE (Biozzi et al., 1982) Sel. Antigens used Immunization proc. No. gen. to sel. Diff. limit (H/L) Heritability Est. No. independ. loci I Sheep eryth. Pigeon eryth. Primary response 16 220 fold .20 9-11 II Sheep eryth. Primary 13 103 fold .21 2-8 III Salm. typh. Secondary 16 90 fold .20 4-7 IV Salm. typh. Secondary 12 85 fold .21 2-4 V Bov. Ser. Alb. Heperimmun Rabbit gamma alum precip. globulin antigen 7 310 fold .22 2-4 SUMMARY OF RESULTS ON RESISTANCE OF HIGH (H) AND LOW (l) MICE TO VARIOUS INFECTIONS (Biozzi et al., 1982) Infection F berghei Antibody T. Cruzi dependent immunity N. dubius Rabies virus T Spiralis S typohimurium Macrophage dependent immunity T. pestis B. abortus suis L tropica S. mansoni Degree of resistance Innate resistance Acquired resistance H L H L - - +++ + +++ - - n.d. +++ + ++ + +++ ++ + ++ + + + + + ++ ++ ++ +++ ++ + + ++ n.d. +++ ++++ ++++ ++++ n.d. +++ 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. All types of mild endemic infections macrophage dependent immunity antibody dependent immunity Severe epidemic infections Severe epidemic infections H X L cross F2 hybrids Antibody responsiveness Macrophage activity 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) All types of mild endemic infections antibody dependent Immunity (favors aa genotypes) macrophage dependent Immunity (favors AA genotypes) Severe epidemic infections Severe epidemic infections H X L cross F2 hybrids Antibody responsiveness Macrophage activity 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. Effects of different degrees of dominance on phenotypic value 7 6 5 AA Aa aa 4 3 2 1 0 No Dominance (additive) Complete dominance Partial dominance Overdominance 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.