Impact of Grow-Finish Performance and Carcass Characteristics in Response to an Increased Apparent Health Challenge

A health challenge can cause significant loss of profit for a production system. The objective of this experiment was to quantify the impact of an apparent health challenge on growth performance and carcass characteristics. Within each of 3 barns, ~900 pigs (13.1 ± 0.2 kg) were split by weight and blocked by sex (16 barrow pens, 16 gilt pens and 4 mixed sex pens). Each barn was categorized based on the apparent health status as low challenge (LC), moderate challenge (MC), or high challenge (HC). Apparent health status was determined based on results from quantitative diagnostic assessments and mortality rates. Over the duration of the study, barns were diagnosed with porcine reproductive and respiratory syndrome virus, influenza and secondary bacterial pathogens varying in combination. Mortality was 4.1%, 7.7%, and 21.2% for LC, MC, and HC, respectively. All barns were marketed at a common weight (~131.5 ± 1.3 kg), in a three cut structure. Data were analyzed using the PROC MIXED procedure of SAS (9.3) with pen as the experimental unit, start weight as a covariate, apparent health status and sex as fixed effects, and block as a random effect. There was a decrease in ADG and ADFI with increased health challenge (P < 0.01). Feed efficiency was greatest in LC but the same in the MC and HC (P < 0.01). The MC and HC barns had greater HCW than the LC barn (P < 0.01). This was similar for percent yield (P < 0.01). However, there was no difference for percent lean or fat depth between the three health statuses (P > 0.05). In conclusion there was a decrease in ADG, ADFI and feed efficiency with an increase in health challenge. There was a difference in percent yield but no difference for percent lean or fat depth.

	Health Status
Item	LC	MC	HC	SEM	P-value
ADG, kg	0.86a	0.79b	0.73c	0.01	< 0.0001
ADFI, kg	2.05a	2.00a	1.82b	0.04	< 0.0001
G:F	0.42a	0.40b	0.40b	0.004	< 0.0001
HCW, kg	93.55b	98.23a	97.60a	0.99	< 0.0001
Yield, %	72.37b	74.13a	73.60a	0.21	< 0.0001
Lean, %	55.05	54.78	54.80	0.29	0.525
Fat, mm	18.05	18.54	18.52	0.39	0.303