Animal welfare standards have been incorporated in EU legislation and in farm assurance schemes, based on scientific information and aiming to safeguard the welfare of the species concerned. Recently, emphasis has shifted from resource-based measures of welfare to animal-based measures, which are considered to assess more accurately the welfare status. The data used in this analysis were collected from April 2013 to May 2016 through the ‘Real Welfare’ scheme in order to assess on-farm pig welfare, as required for those finishing pigs under the UK Red Tractor Assurance scheme. The assessment involved five main measures (percentage of pigs requiring hospitalization, percentage of lame pigs, percentage of pigs with severe tail lesions, percentage of pigs with severe body marks and enrichment use ratio) and optional secondary measures (percentage of pigs with mild tail lesions, percentage of pigs with dirty tails, percentage of pigs with mild body marks, percentage of pigs with dirty bodies), with associated information about the environment and the enrichment in the farms. For the complete database, a sample of pens was assessed from 1928 farm units. Repeated measures were taken in the same farm unit over time, giving 112 240 records at pen level. These concerned a total of 13 480 289 pigs present on the farm during the assessments, with 5 463 348 pigs directly assessed using the ‘Real Welfare’ protocol. The three most common enrichment types were straw, chain and plastic objects. The main substrate was straw which was present in 67.9% of the farms. Compared with 2013, a significant increase of pens with undocked-tail pigs, substrates and objects was observed over time (P<0.05). The upper quartile prevalence was <0.2% for all of the four main physical outcomes, and 15% for mild body marks. The percentage of pigs that would benefit from being in a hospital pen was positively correlated to the percentage of lame pigs, and the absence of tail lesions was positively correlated with the absence of body marks (P<0.05, R>0.3). The results from the first 3 years of the scheme demonstrate a reduction of the prevalence of animal-based measures of welfare problems and highlight the value of this initiative.

From 2013-2016, animal-based measures were collected as part of the "Real Welfare" protocol adopted by the Red Tractor Pigs Assurance Scheme to assess the welfare in finisher pig herds in the UK. Trained veterinarians from 89 veterinary practices assessed 112,241 pens (hospital pens excluded) from 1928 farms using a multistage sampling protocol, and collected data about pig welfare, management and farm environment. Multivariable analyses were conducted for five main welfare outcomes: lameness, pigs requiring hospitalization, severe tail lesions, severe body marks and enrichment use ratio (number of active pigs interacting with the enrichment/total number of active pigs). Additionally, a multiple correspondence analysis (MCA) was conducted to analyse systematic patterns of variations of environmental characteristics and improve understanding of the connection between welfare outcomes and environment. The prevalence of the four welfare outcomes and the mean enrichment use ratio differed between pen types (P<0.05), with a higher mean prevalence of lame pigs (0.39%) but lower mean prevalence of pigs requiring hospitalization (0.07%), severe tail lesions (0.07%) and severe body marks (0.12%) in outdoor pens. In&outdoor pens had the highest mean prevalence of the measured outcomes (P<0.05). After adjusting for the farm, date and pen type, lameness, pigs requiring hospitalization and severe tail lesions were less prevalent in large pens (P<0.01), pens with substrates (P≤0.05) and pens fed with meal (P≤0.05), while enrichment use ratio was higher with substrates (P<0.001). Moreover, pigs requiring hospitalization and severe body marks were more prevalent in pens with powered ventilation (P<0.05). On the MCA graph, higher prevalences of lameness and pigs requiring hospitalization (>1, 5 and 10%) were located in the same direction as lower enrichment use ratio, liquid feed, trough feeding, floor feeding, restricted feed and in&outdoor pens. Results suggested that higher prevalences were not specifically connected to a particular system, but that all welfare outcomes were connected to several inappropriate features in the environment. This study highlights individual risk factors which can be considered to improve animal welfare, but also indicates the need to consider the environment as a whole because of potential factor combinations and confounds. Understanding of these requires a large scale database, which can be drawn from assessments carried out as part of farm assurance and support evidence-based advice and future formulation of standards for good practice.

A meta-analysis on the effects of management and animal-based factors on the performance and feed efficiency of growing pigs can provide information on single factor and interaction effects absent in individual studies. This study analysed the effects of such factors on average daily gain (ADG), feed intake (FI) and feed conversion ratio (FCR) of grower and finisher pigs. The multivariate models identified significant effects of: (1) bedding ( P < 0.01), stage of growth ( P < 0.001) and the interaction bedding × lysine ( P < 0.001) on ADG. ADG was higher on straw compared with no bedding (710 v. 605 g/day). (2) FI was significantly affected by stage of growth ( P < 0.01), bedding ( P < 0.01), group composition ( P < 0.05), group size ( P < 0.01), feed CP content ( P < 0.01), ambient temperature ( P < 0.01) and the interaction between floor space and feed energy content ( P < 0.001). Pigs housed on straw had a lower FI in comparison with those without (1.44 v. 2.04 kg/day); a higher FI was seen for pigs separated by gender in comparison with mixed groups (2.05 v. 1.65 kg/day); FI had a negative linear relationship with group size, the CP content of the feed and ambient temperature. (3) Stage of growth ( P < 0.001), feed CP ( P < 0.001) and lysine content ( P < 0.001), ambient temperature ( P < 0.001) and feed crude fibre (CF) content ( P < 0.01) significantly affected FCR; there were no significant interactions between any factors on this trait. There was an improvement in FCR at higher ambient temperatures, increased feed CP and lysine content, but a deterioration of FCR at higher CF contents. For ADG, the interaction of bedding × lysine was caused by pigs housed without bedding (straw) having higher ADG when on a feed lower in lysine, whereas those with bedding had a higher ADG when on a feed higher in lysine. Interaction effects on FI were caused by animals with the least amount of floor space having a higher FI when given a feed with a low metabolisable energy (ME) content, in contrast to all other pigs, which showed a higher FI with increased ME content. The meta-analysis confirmed the significant effect of several well-known factors on the performance and efficiency of grower and finisher pigs, the effects of some less established ones and, importantly, the interactions between such factors.Keywords: efficiency, finishers, growers, meta-analysis, pigs ImplicationsThe effects of management and animal-based factors on daily gain, feed intake (FI) and feed efficiency of grower and finisher pigs were analysed. A number of factors were identified as having significant effects on these traits, including the effects of less well-established ones, such as the effects of grouping by gender on FI. Interactions between factors were also confirmed; for example, the interaction between bedding and feed lysine content on daily gain. The results may contribute towards the improvement of efficiency of pig systems through a better knowledge of the various factors that influence it. IntroductionFeed efficiency is one of the ...

A meta-analysis on the effects of management and animal-based factors on the reproductive efficiency of gestating sows can provide information on single-factor and interaction effects that may not have been detected in individual studies. This study analyzed the effects of such factors on the number of piglets born alive per litter (BA), piglet birth weight (BiW) and weaning weight (WW), and number of piglets born alive per kilogram of sow feed intake during gestation (BA/FI). A total of 51 papers and 7 data sources were identified for the meta-analysis, out of which 23 papers and 5 sets of production data were useable (a total of 121 treatments). The information gathered included the dependent variables as well as information regarding animal, management, and feed characteristics. While a number of factors were individually significant, the multivariate models identified significant effects only of 1) floor type (P=0.003), sow BW at the end of gestation (P=0.002), and housing (stalls vs. loose; P=0.004) on BA; as floor type and housing were confounded, they were included in 2 separate models. The BA was higher on solid (12.1) in comparison to partly slatted (11.4) and fully slatted floors (10.2); 2) sow gestation environment (P=0.017) and gestation feed allowance (P=0.046) on BiW, with BiW of pigs higher for sows kept outdoors rather than indoors (1.75 versus 1.49 kg); 3) parity number (P=0.003) and feed intake during gestation (P=0.017) on WW; in addition there was an interaction between parity number×feed ME and parity number×feed CP content of feed during gestation on WW, with the positive effects of feed ME and CP contents seen during early rather than later parities; and 4) floor type (P=0.019) and feed crude fiber (P=0.003) for BA/FI with a greater number for those kept on solid floors (5.11) versus partially and fully slatted floors (4.07 and 4.05). The meta-analysis confirmed the significant effect of several well-known factors on the efficiency of gestating sows and, importantly, the interactions between these factors. In addition, the effects of some less established factors were noted, such as floor type. The results may contribute towards the improvement of efficiency of gestating sow systems by better understanding of the various factors that influence this.