Evaluating sow welfare - Essay Example

In this case, the common systems included tethers, stalls, and other group housing system. Meta-analysis results established that the average level of oral-nasal-facial, productivity and blood cortisol concentrations were similar for sows in stalls and group pens (McGlone et al. 2004). For the review, housing system does not change heart rate, but circulating cortisol concentrations were higher among gestating sows kept in tether than other housing systems. The review also identified that gestation housing system sometimes influences sow behavior, including social behavior, stereotypic ONF, feeding behavior, or postural locomotory (McGlone et al. 2004). In order to validate their review’s results, this paper provides a critical analysis of the meta-analysis and other measures employed to compare the welfare of sows, in these two systems.

This paper further investigates whether the meta-analysis and numbers presented justify the study’s conclusion. Meta-analysis is a statistical method that is used to compare the results of several independent researches that are considered as “combinable”. . Researchers using this method are required to write a detailed research protocol, in advance, and clearly state the study’s objectives, develop the hypothesis to be tested, the subjects of interest, and propose criteria and procedures for identifying and selecting valid studies and obtaining and analyzing data (McGlone et al. 2004). The method for selecting relevant studies should be well delineated with much focus on whether the search will include unpublished studies, whose results may significantly differ from published trials.

It is usually recommended considering unpublished studies, in meta-analysis since one that is restricted to published studies may produce irrelevant results due to biases of such publications. Most researchers usually obtain published studies from electronic databases or Cochrane Controlled Trial Register. The results obtained from different studies must then be expressed in a standardized format to make their comparison easier. This method employs weighted average of the results to compare different research findings.

In this context, larger trials have more effects than the smaller trials. In McGlone et al. review, the authors performed meta-analysis by extracting data from published scientific papers. They used the mean value for treatment in each scientific paper as the experimental unit for performing meta-analysis (McGlone et al. 2004). For instance, if the weighted values from an unreplicated pen were present in the paper, then they were considered for meta-analysis since each study represented a single observation.

It is worth noting that the meta-analysis presented in Table 1 significantly justifies the study’s conclusions. In this