Intensive Animal Research Articles

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Unidirectional animal-to-human transmission of methicillin-resistant Staphylococcus aureus ST398 in pig farming; evidence from a surveillance study in southern Italy

BackgroundLivestock-associated methicillin-resistant Staphylococcus aureus (MRSA) belonging to clonal complex 398 is recognized as an occupational hazard for workers employed in intensive animal husbandry, especially in the swine-breeding chain. In this study, we compared the prevalence and epidemiological type of MRSA isolates from swine and farm workers in a large area of southern Italy.MethodsBetween January and March 2018, 88 workers from 32 farms where we had previously performed a survey for MRSA colonization of farmed pigs, were sampled by nasal swabbing. A follow-up investigation was conducted on seven workers 1 year after primary screening. MRSA isolates were characterized by MLST, spa and SCCmec typing, and tested for susceptibility to 15 antimicrobials. Epidemiological correlations between human and swine MRSA isolates were supported by Rep-MP3 and RAPD PCR fingerprinting, and whole-genome sequencing.ResultsThe overall colonization rate of MRSA in swine farm workers was 21.6%, being significantly higher in intensive farms and in workers with direct animal contact. All human MRSA isolates were multi-drug resistant, belonged to the ST398 livestock clade, and did not carry Panton-Valentine leukocidin and enterotoxin genes. Notably, 94.1% of human MRSA isolates belonged to the same epidemiological type as swine MRSA isolates from the corresponding farm. Persistent MRSA carriage was documented in some workers 1 year after primary sampling.ConclusionsWe report a high prevalence of MRSA among swine farm workers, with higher colonization rates associated with intensive breeding and animal exposure. Our findings suggest unidirectional animal-to-human transmission of LA-MRSA and denote the high zoonotic transmissibility of the ST398 livestock clade.

Preparation of dissociated mouse primary neuronal cultures from long-term cryopreserved brain tissue

BackgroundDissociated primary neuronal cultures are widely used as a model system to investigate the cellular and molecular properties of diverse neuronal populations and mechanisms of action potential generation and synaptic transmission. Typically, rodent primary neuronal cultures are obtained from freshly-dissociated embryonic or postnatal brain tissue, which often requires intense animal husbandry. This can strain resources when working with genetically modified mice. New methodHere we describe an experimental protocol for frozen storage of mouse hippocampi, which allows fully functional dissociated primary neuronal cultures to be prepared from cryopreserved tissue. ResultsWe show that thawed hippocampal neurons have functional properties similar to those of freshly dissociated neurons, including neuronal morphology, excitability, action potential waveform and synaptic neurotransmitter release, even after cryopreservation for several years. Comparison to the existing methodsIn contrast to the existing methods, the protocol described here allows for efficient long-term storage of samples, allowing researchers to perform functional experiments on neuronal cultures from brain tissue collected in other laboratories. ConclusionsWe anticipate that this method will facilitate collaborations among laboratories based at distant locations and will thus optimise the use of genetically modified mouse models, in line with the 3Rs (Replacement, Reduction and Refinement) recommended for scientific use of animals in research.

Bioaccumulation of heavy metals from wastewater through a Typha latifolia and Thelypteris palustris phytoremediation system

Animal production is a source of heavy metals in livestock wastewater and also a key link in the food chain, with negative impacts on human and animal health. In intensive animal production systems, the most critical elements are zinc and copper. In order to development of innovative non-invasive strategies to reduce the environmental impact of livestock, this study assessed the ability of two plants, Typha latifolia and Thelypteris palustris, to bioaccumulate the heavy metals used in animal nutrition, from wastewater. Four mesocosms (width 2.0 m, length 2.0 m, 695 L of water, 210 kg of soil) were assembled outdoors at the Botanical Garden. Two of them were planted with T. latifolia (TL treated, n = 30; TL control, n = 30) and two with T. palustris (TP treated, n = 60; TP control, n = 60). In T0 a solution of a mineral additive premix (Zn 44.02 mg/L; Cu 8.63 mg/L) was dissolved in the treated mesocosms. At T0, d 15 (T1) and d 45 (T2) samples of roots, leaves, stems, soil and water were collected, dried, mineralized and analyzed using ICP-MS in order to obtain HMs content. We found that T. latifolia and T. palustris accumulate and translocate Zn, Cu from contaminated wastewater into plant tissues in a way that is directly related to the exposure time (T2 for Zn: 271.64 ± 17.70, 409.26 ± 17.70 for Cu: 47.54 ± 3.56, 105.58 ± 3.56 mg/kg of DM, respectively). No visual toxicity signs were observed during the experimental period. This phytoremediation approach could be used as an eco-sustainable approach to counteract the output of heavy metals.

World food security, globalisation and animal farming: unlocking dominant paradigms of animal health science.

This paper presents a critical review of intensive animal farming in the light of past and present global crises, reflecting the fragility of its foundations, its unsustainability and its inability to ensure world food security. A central argument of this paper is that intensive animal farming promotes industrial efficiency, commodity production and the availability of cheap food at the expense of farmed animals, the environment and society. This paper begins by briefly examining the history of world food security and explores the role assigned to animal farming, animal health and public health in this context. It then reviews changing perceptions of world food security during various periods of global instability and their implications for animal farming and animal health and welfare. At the same time, the paper seeks to identify what has so far been missing in discourses around world food security and animal farming, and discusses how these gaps shape and are shaped by specific scientific thinking on animal health and well-being. With the recent exponential growth of aquaculture, the authors' objectives are to examine animal health practices in farming and to understand how animal health science could effectively, in the long term, help animal farming, and in particular aquaculture, to contribute to global food security.

Responding to the problem of ‘food security’ in animal cruelty policy debates: building alliances between animal-centred and human-centred work on food system issues

Research on ethical issues within food systems is often human-centric. As a consequence, animal-centric policy debates where regulatory decisions about food are being made tend to be overlooked by food scholars and activists. This absence was notable in the recent debates around Australia’s animal live export industry. Using Foucault’s tools, we explore how ‘food security’ is conceptualised and governed within animal cruelty policy debates about the live export trade. The problem of food security produced in these debates shaped Indonesians as ‘victims’ of food insecurity due to the nation’s inability to produce sufficient quantities of protein. This understanding of the problem reproduced the dominant framing of food security as a problem for developing countries addressed by increasing global food production. The underlying premise uncritically accepted in Australia’s debates on live export trade was that intensive animal agriculture, and Australia’s live export trade specifically, were essential to alleviating global food insecurity. Drawing on our findings, we show how dominant representations of ‘food security’, and related regulatory and technological trajectories, flourish where alliances between animal and food activists, scholarship, and movements are weak. Accordingly, we argue for agri-food scholars to take up opportunities to contribute to the policy discussions about the treatment of animals to effectively expand the kinds of problems, solutions, and strategies of resistance produced in the discourses surrounding food system issues.

Characterization of bacterial isolates from skin lesions of sheep, goat and cattle in different rearing condition

The study was performed to isolate and characterize some selected bacteria from skin lesion of sheep, goat and cattle of different rearing condition. Intensive and semi-intensive housing systems were considered for this study. A total of (n=60) skin wound swab and pus samples were collected for this study during the study period. Among them (n=30) samples were collected from intensive farms and (n=30) samples were collected from semi-intensive farms. Staphylococcus aureus infections were found 70% skin lesion for sheep, 30% for goat and 60% for cattle and Pseudomonas aeruginosa infections were found 5% skin lesion for sheep, 15% for goat and 15% for cattle. Semi-intensive farm animals were more infected by bacteria than intensive farm animals. Staphylococcus aureus affected 53.33% in intensive farm animal and 66.67% in semi-intensive farm animal. Pseudomonas aeruginosa affected 10% animal in intensive housing system and 13.33% in semi-intensive housing system. The organisms were isolated and characterized by morphological, cultural and biochemical characteristics and identified by polymerase chain reaction. Staphylococcus aureus produced yellowish colony in nutrient agar and golden yellow colony in mannitol salt agar. Positive isolates were produced β–hemolysis in blood agar. Pseudomonas aeruginosa produced characteristic colony in nutrient agar but not produce pigment. Pseudomonas aeruginosa produced colorless colony in MaCconkey agar, violet colony in EMB agar and produced hemolysis in blood agar. Staphylococcus aureus showed Gram positive, cocci shaped and grapes like arrangement and Pseudomonas aeruginosa showed Gram negative, short rod shaped. Staphylococcus aureus fermented five basic sugars and produced gas and Pseudomonas aeruginosa fermented dextrose and mannitol. Both organisms were catalase positive, only Pseudomonas aeruginosa was oxidase positive. Pseudomonas aeruginosa isolates were further characterized by PCR amplification of toxA gene primer. Staphylococcus aureus skin infection treatment was noticed more effective by erythromycin and gentamicin and Pseudomonas aeruginosa skin infection treatment more effective by ciprofloxacin and gentamicin. Both the organisms were found to be amoxicillin resistant. This is the first and preliminary report of molecular characterization of Pseudomonas aeruginosa from skin lesion of sheep, goat and cattle associated with a different rearing condition of the animals in Bangladesh.&#x0D; Asian J. Med. Biol. Res. June 2019, 5(2): 117-125

Evaluating Ammonia (NH3) Predictions in the NOAA NAQFC for Eastern North Carolina Using Ground Level and Satellite Measurements

AbstractAmmonia (NH3) in the atmosphere contributes to the formation of airborne fine particulate matter (PM2.5), which is associated with adverse human health effects. The emission, transport, reactions, and deposition of NH3 in the atmosphere are modeled using the Community Multiscale Air Quality (CMAQ) model, within the U.S. National Air Quality Forecast Capability (NAQFC). The purpose of this current work is to evaluate the capability of the NAQFC CMAQ model and to identify potential improvements to NH3 emissions estimates and prediction methods. This study focuses on CMAQ predictions of atmospheric NH3 in North Carolina, including a region with intensive animal production and enhanced NH3 emissions. The CMAQ model is run for July 2011 using a version of the 2011 National Emissions Inventory in which agricultural NH3 emissions were adjusted to reflect the lower end of the range of estimates from the current process‐based emissions model. The NAQFC CMAQ model overpredicted atmospheric NH3 at a continuous monitor in Clinton, NC, within the region of intensive animal production. The average concentration measured by the monitor was 6.6 ppbv, while the average predicted by the model was 10.5 ppbv, a 60% overprediction. Outside of the region of intensive animal production, both measured and modeled NH3 concentrations were low, 1.3 ppbv or less. The model underpredicted wet deposition of NH4+ and dry deposition of NH3. It is believed that the overestimation of NH3 at Clinton is attributable at least in part to the underestimation of wet and dry deposition in North Carolina.

Potential benefits of gene editing for the future of poultry farming.

The chicken is an exemplar of efficient intensive animal agriculture and provides two valuable food products, chicken meat and eggs. Only aquaculture is better, by efficiency, but poultry is still top, by mass of animal protein produced as food in the global context. However this efficiency and intensive production comes with a number of challenges. Though the genetics of selective breeding have led to dramatic improvements in yield, efficiency and product quality, traits that relate to disease and welfare outcomes have not been so tractable. These two issues are major impacts to the industry in terms of production and in terms of public perception. Both transgenic technology and genome editing have clear potential for impact in these two important areas. The reproductive biology of birds requires techniques very specific to birds to achieve heritable (germline) edited traits. These are quite involved and, even though they are now well-defined and reliable, there is room for improvement and advances can be expected in the future. Currently the key targets for this technology are modifying chicken genes involved in virus-receptor interactions and cellular response involved in infection. For the egg industry the technology is being applied to the issue of sex-selection for layer hens (and the removal of males), removal of allergens from egg white and the tailoring of eggs system to enhance the yield of influenza vaccine doses. Regulation and trading of the animals generated, and resulting food products, will significantly impact the value and future development of genome editing for poultry.

A promising strategy for nutrient recovery using heterotrophic indigenous microflora from liquid biogas digestate

Nutrient overloading resulting from digestate (effluent of anaerobic digestion process) application has become a major bottleneck for the development of the biogas industry and raised environmental concerns in regions with intensive animal husbandry. Due to this, it is imperative to find low cost and effective alternative to export nutrient from digestate. Among the numerous applications, indigenous microflora has recently been utilized successfully as a biofloc technology in aquatic systems for controlling ammonia and subsequent reduction of feeding cost. Accordingly, performance of the indigenous microflora in undiluted liquid digestate of chicken manure was evaluated in this study to recover nutrients and produce high-value biomass under aerobic heterotrophic mode in batch shaking experiments. The results showed that 68% of phosphate was recovered and 97% of total nitrogen was removed from the liquid digestate. Additionally, >6 g L−1 of dry biomass was simultaneously produced and featured with up to 65% crude protein without pathogens, 10.9% lipids, 10.7% ash and 19.6 MJ kg−1 gross energy. Therefore, the produced biomass could be used either as an alternative sustainable source for animal or fish feeding or as a substrate for energy applications.

Detection of Virulence Genes in Multidrug Resistant Enterococci Isolated from Feedlots Dairy and Beef Cattle: Implications for Human Health and Food Safety.

The misuse/abuse of antibiotics in intensive animal rearing and communities led to the emergence of resistant isolates such as vancomycin-resistant enterococci (VREs) worldwide. This has become a major source of concern for the public health sector. The aim of this study was to report the antibiotic resistance profiles and to highlight the presence of virulence genes in VREs isolated from feedlots cattle of the North-West Province of South Africa. 384 faecal samples, 24 drinking troughs water, and 24 soil samples were collected aseptically from 6 registered feedlots. Biochemical and molecular methods were used to identify and categorise the enterococci isolates. Their antibiotic resistance profiles were assessed and genotypic methods were used to determine their antibiotic resistance and their virulence profiles. 527 presumptive isolates were recovered, out of which 289 isolates were confirmed as Enterococcus sp. Specifically, E. faecalis (9%), E. faecium (10%), E. durans (69%), E. gallinarum (6%), E. casseliflavus (2%), E. mundtii (2%), and E. avium (2%) were screened after molecular assays. VanA (62%), vanB (17%), and vanC (21%) resistance genes were detected in 176 Enterococcus sp., respectively. Moreover, tetK (26), tetL (57), msrA/B (111), and mefA (9) efflux pump genes were detected in 138 VRE isolates. Multiple antibiotic resistances were confirmed in all the VRE isolates of this study; the most common antibiotic resistance phenotype was TETR-AMPR-AMXR-VANR-PENR-LINR-ERYR. CylA, hyl, esp, gelE, and asa1 virulence genes were detected in 86 VREs with the exception of vancomycin-resistant E. mundtii isolates that did not display any virulence factor. Most VRE isolates had more than one virulence genes but the most encountered virulence profile was gelE-hyl. Potentially pathogenic multidrug resistant VREs were detected in this study; this highlights the impact of extensive usage of antimicrobials in intensive animal rearing and its implications on public health cannot be undermined.

Improved management increases carrying capacity of Brazilian pastures

Grazing pasture without appropriate soil conservation and animal management often leads to reduced soil quality and decreased productivity because of trampling induced compaction. Our objective was to evaluate the effect of three conservation-based pasture management strategies on soil physical attributes. The treatments were (1) Brachiaria decumbens + mineral-N fertilization, (2) mixed pasture + legume (forage peanut, Arachis pintoi), and (3) Brachiaria without fertilization were compared with a native grassland reference area without management. The hypothesis is that nitrogen fertilization favors an increase in the animal stocking rate, maintaining the physical quality of the soil. The treatments had no significant effect on soil porosity, bulk density, or water retention. The S-index showed that intense animal trampling in the treatment with nitrogen fertilization resulted in the most intense degradation. Mixed pasture with the intercropped legume and N-fertilization maintained soil physical quality similar to the area without management, reinforcing the importance of appropriate soil management practices in pasture. However, although the N-fertilized area had soil physical quality similar to the others, it could support more animals, suggesting an economic advantage over other soil management practices. To preserve or enhance soil physical quality, mixed pastures and fertilization can be adopted, increasing the soil load-bearing capacity, which represents more animals per area.

The Expansion of Intensive Beef Farming to the Brazilian Amazon

Systems of intensive animal farming, such as the confinement of beef cattle, are widespread in the developed world. Such practices have been under scrutiny since the 1960s for animal welfare and pollution issues. Here, we document the expansion of intensive beef farming to the Brazilian Amazon in order to assess socio-environmental implications. Using a combination of data mining and field surveys, we developed a georeferenced dataset of 201 cattle confinements in the states of Mato Grosso (Cerrado and Amazon biomes), Pará and Rondônia (Amazon biome), collected in 2017. In Mato Grosso, the country’s agribusiness powerhouse, confinements are well established and account for ˜20% of the cattle slaughter. But rapid expansion in Pará and Rondônia remains largely unnoticed due to the absence of data since 2012. We used the new dataset to map cattle confinements across space and time. For the first time, (1) we document an expansion to the Amazon biome; (2) we also show that confinements are associated with substantially higher productivity rates, though intensified pasture-based systems can reach comparable yields; (3) that confinements have crop production levels 2-3 times higher than comparable properties, both in- and out-of-farm; and (4) that confinements tend to slow down on-property deforestation when compared to fattening ranches in the Amazon biome, although off-property effects could be substantial and need further study. Overall, the implications of intensive beef farming for animal welfare and local waste generation in Brazil require attention as pressure to avoid deforestation continues to stimulate the practice.

Therapeutics of neonatal asphyxia in production animals: a review

The aim of this review is to assess the different treatments and therapeutic protocols used for neonatal asphyxia in animal production. Perinatal asphyxia is considered to be one of the main non-infectious causes of neonatal mortality in the majority of domestic mammals. However, its incidence in intensive animal production is increasing because of a series of implemented strategies aimed at improving and increasing production. For example, through the application of genetics, an increase in size and weight in newly born animals has been achieved. Nevertheless, this has resulted in a larger incidence of dystocia associated with oxygen restriction to thefoetus, which elicits metabolic and respiratory acidosis. Furthermore, aside from immediate financial implications when it comes to production, it also has an impact on the welfare of mother and offspring. Regarding the field of animal perinatology, several therapeutic strategies using respiratory and hormonal stimulants, as well as energetic supplements have been evaluated with the aim of preventing perinatal asphyxia and treating neonates with the condition, and also to diminish the incidence of stillbirths associated with it. However, during the last decades this condition has persisted mainly in porcine, equine, ovine and bovine production; for this reason, it continues to be studied extensively.

Concentrations, fluxes, and potential sources of nitrogen and phosphorus species in atmospheric wet deposition of the Lake Qinghai Watershed, China

Plateau lakes are typically dystrophic and are sensitive to small changes in nutrient deposition. With this assumption, we investigated the concentrations, fluxes, and sources of nitrogen (N) and phosphorus (P) in the atmospheric wet deposition (AWD) of the Lake Qinghai Watershed (LQW), which is the largest inland lake in China, for one year from October 2017 to September 2018. The results showed that the annual volume-weighted mean (VWM) concentrations (mg L−1) in the AWD were 1.97 for NH4+-N, 0.55 for NO3−-N, 0.04 for NO2−-N, 0.77 for dissolved organic N (DON), 3.33 for total dissolved N (TDN), 0.30 for dissolved inorganic P (DIP), 0.07 for dissolved organic P (DOP), 0.36 for total dissolved P (TDP), and 0.99 for reactive sulfur (SO42−-S). The annual AWD fluxes of TDN and TDP were 16.82 and 1.86 kg ha−1 yr−1, respectively. Strong dilution effects in the wet season, a long residency time of nutrient-rich aerosols in the dry season, strong ammonia volatilization in the wet and warm seasons, and moisture sources dominated the seasonal or monthly changing characteristics of N and P concentrations in the AWD, including high in the wet season and low in the dry season for NH4+-N, low in the wet season and high in the dry season for NO3−-N, and generally increasing from April to September for DIP and DOP. Precipitation quantity dominated the monthly changes in the N and P fluxes of the AWD, which gradually increased from April to August and then decreased in September. N and P in the AWD mostly originated from anthropogenic sources. High ammonia volatilization from local intense animal husbandry, alkaline soils and lakes led to a relatively high NH4+-N concentration compared with other sites of the Qinghai-Tibet Plateau, China, and in the world. The N/P molar ratio in the precipitation was higher than 16, which might have effect on the aquatic ecosystems of Lake Qinghai. Ammonia volatilization fluxes and atmospheric dry deposition fluxes of N and P should be further studied to completely understand the geochemical cycles of N and P in the LQW.

From “Meat Culture” to “Cultured Meat”: Critically Evaluating the Contested Ontologies and Transformative Potential of Biofabricated Animal Material on Culture and Law

This article calls into question how different the parallel ontologies of meat are in terms of the realities they enact. It argues that while biofabricated animal material is expected to transform the production and consumption of meat, the material’s ontologies reinforce existing interrelationships between the dominant meat culture and the law. Additionally, the expectations surrounding biofabricated animal material vests the material with transformative power, even though it does not challenge the structural factors, namely law and culture, which underlie the exploitation and commodification of animals. I begin by delineating the co-constituting relationship between law, the realities of meat production and consumption, and meat culture. I then unpack the interface between different ontologies of meat and consider why the contest has taken place in legal terrains. From here, I consider the key expectations that have assigned transformative power to biofabricated animal material. I suggest that these expectations work to reinforce existing meat culture, and the configurations of power that benefit from it, as supported via legal instruments.

Animals Australia and the Challenges of Vegan Stereotyping

Animals Australia and the Challenges of Vegan Stereotyping

Hajj abattoirs in Makkah: risk of zoonotic infections among occupational workers.

At completion of Hajj, the Islamic pilgrimage to Makkah, pilgrims give thanks for the blessing, and acceptance, of Hajj, marking the end of the pilgrimage by sacrificing an animal and distributing the sacrificial meat to the poor. With over two million Muslims making Hajj, each Hajj, more than 1.2 million heads of cattle: sheep, goats and camels are slaughtered. Over 16 000 abattoir workers work around the clock to sacrifice and process the cattle in keeping with Islamic law and public health guidelines. Because of their proximity to high densities of cattle and cattle meat, Makkah's abattoir workers are at risk of zoonosis. This was a longitudinal study aimed at determining the risk of some zoonotic diseases among male permanent abattoir workers during Hajj. Specifically, seroprevalence of antigens for Brucella, Crimean–Congo haemorrhagic fever (CCHF), Alkhurma haemorrhagic fever (AHF) and Rift Valley Fever (RVF) were determined, among the study participants. An enrolment questionnaire, and a follow‐up questionnaire, with provision of 10 mL blood for testing 2 days before intense Hajj animal exposure, up to 20 days after intense animal exposure and between 30 and 42 days after Hajj butchering exposures. While working with livestock, study participants were interrogated on hand hygiene and personal protection. Eighty male permanent abattoir workers participated in the study. Majority, 96.25% (n = 77) declared washing their hands with soap and water, most 98.75% (n = 79) never used eye protection, few occupational workers dressed in personal protective clothing or footwear. All workers tested negative for CCHF and RVF, one was positive for AHF and six for Brucella. The risk of some zoonotic infections like Brucella and AHF is low among permanent occupational workers in the slaughtering house in Makkah during Hajj 2013. No serological evidence for CCHF and RVF viruses, even though workers showed low compliance with use of personnel protective equipment.

Deep learning to map concentrated animal feeding operations

Enforcement of environmental law depends critically on permitting and monitoring intensive animal agricultural facilities, known in the United States as ‘concentrated animal feeding operations’ (CAFOs). The current legal landscape in the United States has made it difficult for government agencies, environmental groups and the public to know where such facilities are located. Numerous groups have, as a result, conducted manual, resource-intensive enumerations based on maps or ground investigation to identify facilities. Here we show that applying a deep convolutional neural network to high-resolution satellite images offers an effective, highly accurate and lower cost approach to detecting CAFO locations. In North Carolina, the algorithm is able to detect 589 additional poultry CAFOs, representing an increase of 15% from the baseline that was detected through manual enumeration. We show how the approach scales over geography and time, and can inform compliance and monitoring priorities. Machine learning and satellite images are used to identify intensive animal agricultural facilities in the United States, which are otherwise difficult to track. This can facilitate monitoring their compliance with environmental law.

Technical Note: Effects of age and confinement on pupillary light reflex in sows1

Pupillary reflex has been used as a method to examine psychological problems in human clinics and mental disease research. Intensive animal farming has been shown to lead to chronic stress resulting in depression; however, comparing with humans we lack an effective clinical method to clinically inspect these psychological problems in animals. The goal of this study was to investigate the effect of age and housing conditions (confined crates vs. group pens) on pupillary light reflex (PLR) of sows to explore whether PLR can be used as an effective way to measure the psychological state of farm animals. In total, 270 pregnant sows were selected for PLR testing and divided into 6 treatments (45 sows per treatment) of 2 different environments (group-housed pen and confined gestation crates) and 3 parities (first, third, and fifth parities). Six selected pupil parameters: 1) latency of the pupil constriction onset (LAT); 2) the percent of the constriction (CON); 3) average constriction velocity (ACV); 4) maximum constriction velocity (MCV); 5) average dilation velocity (ADV); and 6) time of 75% recovery after constriction (T75) were examined. The results showed that there was no difference found in these PLR parameters between the breeds (P > 0.05) but the significant effects were found on LAT, CON, ACV, and MCV by age (P < 0.01). The group-housed sows had significantly higher CON, ACV, and MCV than those in the confined crates (P < 0.05). In conclusion, the pupillary light reflex of the sows was not affected by breed but by age. The results also indicate that some of PLR parameters were sensitive to housing conditions and suggest that ACV and MCV have potential to be sensitive indicators in relation to the psychological problem of sows.