Ontario Pork Carcass Appraisal Project Symposium

Appendix 4
Significant Interactions Between Breeds and Sex




Significant breed x sex interactions (based on full model).

Trait
Nature of Interaction
Days to 100 kg (d) Advantage of males over barrows and gilts greatest for Landrace. Difference males - average of (barrow + gilt) = -5.3, -1.6, -4.3 and -5.9 for Duroc, Hampshire, Yorkshire and Landrace.
Average daily gain (kg/d) Hampshire gilts significantly (P < 0.01) faster growing than expected; by 0.038 kg/d.
Backfat at 100 kg (mm) Hampshire and Duroc barrows have lower backfat than expected; by 0.7 and 0.5 mm.
Hot carcass weight (kg) Duroc barrows and gilts lighter than expected; by 1.1 and 1.3 kg.
Dressing %Duroc gilts lower than expected; by 0.83%.
Carcass length (cm) Duroc barrows and gilts longer than expected; by 0.45 and 0.66 cm. Landrace gilts shorter than expected; by 0.38 cm.
Minimum backfat (mm) Duroc and Landrace barrows less fat than expected; by -1.1 and -0.9 mm.
Minimum loin fat (mm) Duroc and Hampshire barrows less fat than expected; by -1.1 and -1.5 mm. Duroc gilts more fat than expected; by 1.4 mm.
Shoulder as % of side Landrace barrows lower % than expected; by -0.3%. Hampshire barrows higher % than expected; by 0.4% (Hampshire gilts higher % than expected; by +0.4%) P = 0.06.
Ham as % of sideHampshire barrows higher % than expected; by 0.4%.
Belly as % of side Duroc barrows and gilts lower % than expected; by -0.3 and ­0.2%.
Estimated lean (new), % Duroc and Landrace barrows higher lean than expected; by 0.8 and 0.8%.
Lean content of ham, % Duroc and Landrace gilts and Landrace barrows less lean than expected; by -0.6, -1.1, -0.9%.
Loin lean as % of 3 primals Duroc barrows more lean than expected; by 0.4%. Hampshire gilts and barrows less lean than expected; by -0.5 and -0.4%.
Drip loss, loin, % Hampshire barrows and gilts less loss than expected; by -0.87 and ­1.13%. Landrace barrows and gilts more loss than expected; by 0.64 and 0.55%. Duroc barrows had less loss than expected; by -0.83%.
Drip loss, ham, %Hampshire barrows and gilts less loss than expected; by -1.36 and ­1.55%.
Belly ratio 1Hampshire barrows and gilts higher ratio than expected, by 0.038 and 0.035.
Belly ratio 3Hampshire barrows and gilts higher ratio than expected, by 0.056 and 0.048.
Marbling score, loin Duroc barrows and gilts, higher score than expected; by 0.25 and 0.21.
Ag. Canada colour, loin Duroc barrows and gilts, and Hampshire barrows and gilts higher colour than expected; by 0.18, 0.11, 0.32 and 0.29 units.
Jap. colour, loinDuroc barrows and Hampshire barrows and gilts higher than expected; by 0.16, 0.26 and 0.14 units.
Ag. Canada structure, loin Hampshire barrows and gilts higher score than expected; by 0.30 and 0.20 units. Duroc gilts and Landrace barrows and gilts lower than expected; by ­0.14, -0.12 and -0.10.
Ag. Canada colour, ham Hampshire barrows and gilts higher than expected; by 0.28 and 0.26 units. Landrace barrows and gilts lower than expected; by 0.16 and 0.22 units.
Ag. Canada structure, ham Hampshire barrows and gilts higher than expected; by 0.25 and 0.18 units. Landrace barrows and gilts lower than expected; by -0.14 and -0.14 units. (Duroc barrows higher than expected; by 0.15 units, P = 0.054).

Notes on Interaction Terms: Statistical analyses use Yorkshire boars, gilts and barrows, as the base to test breed x sex interactions. All deviations quoted are the deviation of the given breed by sex class from the breed + sex deviation. eg. For average daily gain, the Hampshire gilt breed x sex deviation is 0.038 kg/d. This means that the difference between Hampshire and Yorkshire gilts is 0.038 kg/d higher than expected based on the average breed difference between Hampshires and Yorkshires. Put another way, the difference between Hampshire gilts and boars (or barrows) is 0.038 higher than for Yorkshire gilts and boars (or barrows).