Selecting for Robustness in Pigs

Transcription

1 Selecting for Robustness in Pigs Pramod Mathur, Saskia Bloemhof, Hamed Rashidi, Egbert Knol NSIF: Nov 2012

2 Why robustness? Globalization of pork production Global warming Easier spread of diseases and reduction of antibiotics Feed and Labor shortage and costs Genotype x environment interactions Environmental sensitivity

3 How to define robustness? A number of factors Changes in climate, feed, labor, Variation in production: Within sow Between sows Between weeks / seasons Diseases or health challenges Heat stress.

4 How to measure robustness? Adaptability to stressors Parasite burden Immune parameters Heat load Metabolic rate Productive adaptability to stressors Ability to keep up production in spite of stressors Fitness (reproduction) Production

5 Disease tolerance as an indicator trait for robustness

6 How to identify disease phases? Most farms: No data on: virus load lymphocyte count immune parameters Lots of data Production and reproduction

7 Weekly production Number piglets born alive Number piglets born alive Year-weeks

8 Outbreak detection NBA: Number of piglets born alive

9 Outbreak detection Number piglets born alive Healthy Diseased Year-weeks

10 Outbreak detection Number piglets born alive Healthy Diseased Virus isolation Year-weeks

11 Relationship between performance in healthy and disease phases Variance components Number piglets Born Alive Mummified piglets Still-born piglets Bivar. Reac. Norm Bivar. Reac. Norm Bivar. Reac. Norm Healthy phases Disease phases Correlation Bivariate model: Performance in healthy and disease phases as different traits Reaction norm: Quantification of severity of the disease

12 Disease tolerance Disease outbreaks can be detected using data models Disease leads to higher variance Higher host genetic variation available Opportunities for selection to reduce losses

13 Heat tolerance as an indicator trait for robustness

14 Farrowing rates of two lines 32,631 records from 11,935 sows in Spain Source: Bloemhof et al., JAS 2008

15 Genotype x environment interactions Line Constant UCT Slope D I Source: Bloemhof et al., JAS 2008

16 Selection in a different environment Correlations between performance at different production levels Example: Litter size Reaction norms approach and genomic selection

17 Robustness to heat stress Differences between genetic lines in heat tolerance Significant genotype x environment interactions Selection in a different environment can lead to reduction in performance

18 Robustness: Undisturbed production

19 Problem free finisher production Birth Weaning 1 2 Finishing Problem free finishing = 100% 1. Survival from birth to Weaning = 100% 2. Survival from weaning to finishing = 100%

20 Problem Free Sow Production

21 Merry go round Producers like sows that keep up producing from one cycle to the next without problems

22 Problem Free Sow Producton Problem freeness = 100 when: 1. Interval weaning first insemination <= 7 days 2. Non-return rate = 100 % 3. Farrowing rate = 100 % 4. Selection for next cycle = Yes Else: problem freeness = 0

23 Heritability estimates Trait: Heritability (S.E) Problem free sow production 0.06 ± Timely in heat 0.18 ± Non return to estrus 0.06 ± Farrowing rate 0.08 ± Selected for next cycle 0.04 ±0.01 Total number born 0.10 ±0.01 Born alive 0.08 ±0.01 % Born alive 0.04 ±0.01 Number still born 0.06 ±0.01

24 Genetic correlation Problem free sow production No heat stress Heat stress Heritability 0.05 ± ±0.01 Genetic variance 0.06 ± ±0.02 Phenotypic variance 1.25 ± ±0.02 Genetic correlation 0.93 ±0.07

25 Concluding remarks Robustness in pigs can be measured as productive adaptability to stressors There is evidence for strong genotype x environment interactions Selection in a different environment can lead to reduction in performance Need to consider robustness in breeding goals

26 Health Selection and for Environment robustness Platform Breed pigs with enhanced ability to keep up performance in spite of challenges Thanks..!