Removing prophylactic antibiotics from pig feed: how does it affect their performance and health?

Alessia Diana,Declan Murphy,Eugene Sheehan,Laura A Boyle,Edgar G Manzanilla,Ciaran Carroll,Finola C Leonard

doi:10.1186/s12917-019-1808-x

Alessia Diana, Declan Murphy + Show 5 more

Open Access

https://doi.org/10.1186/s12917-019-1808-x

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Abstract

BackgroundAntibiotics (AB) are an important tool to tackle infectious disease in pig farms; however some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed. Little is known about the long term consequences of withdrawing prophylactic AB from pig feed; hence we aimed to assess its effects on performance and health of pigs from weaning to slaughter.Six batches of 140 pigs each were monitored on a commercial farm through the weaner and finisher stages to slaughter. In-feed antibiotics were not added to the feed for half of the pigs (NOI) and were added in the other half (ABI) within each batch for the whole weaner stage. Individual pigs in both treatments were treated with parenteral administrations if and when detected as ill or lame. Productive performance, parenteral treatments and mortality were recorded on farm and the presence of respiratory disease was recorded at slaughter. Pen was considered the experimental unit.ResultsABI pigs showed higher growth (P = 0.018) and feed intake (P = 0.048) than NOI pigs in the first weaner stage but feed efficiency was not affected (NOI = 1.48 vs. ABI = 1.52). Despite an initial reduction in performance, NOI pigs had similar performance in finisher stage (ADG: NOI = 865.4 vs. ABI = 882.2) and minimal effects on health compared to ABI pigs. No difference between treatments was found at the abattoir for the percentage of pigs affected by pneumonia, pleurisy, pleuropneumonia and abscesses (P > 0.05). Mortality rate was not affected by treatment during the weaner stage (P = 0.806) although it tended to be slightly higher in NOI than ABI pigs during the finisher stage (P = 0.099). Parenteral treatments were more frequent in NOI pigs during the weaner stage (P < 0.001) while no difference was recorded during the finisher stage (P = 0.406).ConclusionsThese data suggest that the removal of prophylactic in-feed antibiotics is possible with only minor reductions in productive performance and health which can be addressed by improved husbandry and use of parenteral antibiotics.

Highlights

Antibiotics (AB) are an important tool to tackle infectious disease in pig farms; some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed
On farm measurements Production data, mortality and parenteral administration of antibiotics Pigs with in-feed antibiotics (ABI) pigs had higher Average daily gain (ADG) (P = 0.018) and average daily feed intake (ADFI) (P = 0.048) than Pigs without in-feed antibiotics (NOI) pigs during the first weaner stage which led to 2 kg non-significant difference in final body weight between treatments at the end of the second weaner (P = 0.218) and finisher (P = 0.483; Table 1) stages
There was no difference in ADG, ADFI and feed conversion ratio (FCR) between ABI and NOI pigs during the finisher stage (P > 0.05, Table 1)

Summary

Introduction

Antibiotics (AB) are an important tool to tackle infectious disease in pig farms; some research indicates that their frequent mis/over-use may contribute to the development of antibiotic resistance and the WHO has declared that this issue should be addressed. The pig industry uses more medication (mg of active ingredient / population correction unit) than other livestock sectors, especially during the weaning period [7] when pigs face several challenges and stressors including changes in diet, separation from the sow and re-mixing These changes stress the animals and compromise their immune system [8], making them more susceptible to infectious agents [9, 10]. The practice of prophylactic AB administered via the feed is an easy way of avoiding or reducing the risk of disease in weaned pigs As such use is associated with a high likelihood of broad-spectrum usage or misuse [4, 11] it poses a threat for public health [12, 13]. Parenteral administration of AB would still be allowed, ensuring a more limited and targeted approach

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