<p>  </p> <p>Environmental enrichments have been investigated to determine impacts on turkey health and welfare; however, there is limited data to determine the impact of these enrichments on fresh or processed turkey meat quality. One hundred and forty-four turkeys were randomly assigned to six enrichment treatments: control (C), pecking block (PB), platform (P), platform + straw bale (PSB), straw bale (SB), and tunnel (T). Each treatment was replicated within two rooms in the same barn, with 24 pens total (n = 4 pens/treatment). At 19 weeks of age, turkeys were weighed (live weight, kg), and harvested over two days, with three birds from each pen per day (n=144). A subset of 96 turkeys were fabricated into wings, boneless thighs, drumsticks, and boneless breasts at 24 h postmortem in order to determine carcass cutting yields. From the breast and thigh, three, 1.25 cm samples were taken for pH, proximate analysis, and drip loss. From the breast, three, 2.54 cm samples were taken for instrumental color and sensory analysis, with all remaining breast sample used for further processed boneless turkey breast. Breast portions were pumped with a commercial brine (water, salt, brown sugar, sodium phosphate, sodium erythorbate, and sodium nitrite) to 110% by weight. Brined breast was then vacuum sealed and vacuum tumbled (9 rpm for 90 min, stopping every 15 min for 10 min). Tumbled breast was stuffed into a cellulose casing, thermally processed (internal temperature 68.3oC), and smoked to produce boneless turkey logs. From each log, eight, 1.25 cm slices were taken for packaged purge loss, expressed moisture, instrumental color, and texture and sensory analysis. All treatment levels were analyzed using PROC GLM (SAS 9.4, SAS Institute, Cary, NC). Statistical significance level was set at <em>P≤</em>0.05. For fresh turkey, results showed significant differences in live weight by treatment. SB turkeys weighed the least, PB turkeys weighed the most, and T, PSB, C, and P were intermediate in weight (<em>P=</em>0.008). Treatment did not impact the cut-out values for breasts (<em>P=</em>0.387), thighs (<em>P=</em>0.985), wings (<em>P=</em>0.211), and drumsticks (<em>P=</em>0.575). Treatment did not impact breast L* (<em>P=</em>0.777), a* (<em>P=</em>0.247), or b* (<em>P=</em>0.366) or thigh L* (<em>P=</em>0.936) and a* (<em>P=</em>0.067), but PSB thighs displayed the highest b* values and PB thighs displayed the lowest (<em>P=</em>0.037). Finally, for fresh turkey, treatment did not impact breast drip loss (<em>P=</em>0.766), thigh drip loss (<em>P=</em> 0.933), breast pH (<em>P=</em>0.197), or thigh pH (<em>P=</em>0.385). For processed turkey quality, treatment had no effect on a* (<em>P=</em>0.498) or b* (<em>P=</em>0.831) but was significant for L*. SB, T, P, and PSB had lighter color values, C had darker color values, and PB had intermediate values (<em>P=</em>0.024). Finally, for processed turkey quality, treatment did not impact processing yield (<em>P=</em>0.058) or packaged purge loss (<em>P=</em>0.581), but treatment impacted expressed moisture (<em>P=</em>0.041). PB, PSB, C, and T had higher expressed moisture loss, P had the lowest, and SB had intermediate expressed moisture loss (<em>P=</em>0.041).</p>

<p>    Injurious pecking, aggression, footpad dermatitis and leg abnormalities have been identified as major welfare issues in commercial turkey production, which lead to culling and mortality, downgraded carcass value and economic losses due to decreased productivity and carcass damage. Injurious pecking includes aggressive pecking (head pecking), feather pecking, and cannibalism. Aggressive pecking is related to aggression and is more prevalent in males than females. Feather pecking consists of non-damaging gentle feather pecking and severe feather pecking that can cause feather, skin and tissue damage, and even death in extreme cases. Common methods to control injurious pecking include infrared beak treatment and reduced light intensity, but those methods can result in inconsistent effects on feather condition and negative affect eye development. Footpad dermatitis and leg abnormalities can lead to lameness and an inability of turkeys to access feed and water. </p> <p>    Environmental enrichment, which is the modification of the environment of captive animals to improve their biological functioning, is one alternative way of reducing injurious pecking and potentially improving turkeys’ walking ability. In meat-type poultry production, five types of environmental enrichment are usually used, which include social enrichment, occupational enrichment, physical enrichment, sensory enrichment and nutritional enrichment. For turkeys, some types of physical enrichment such as foraging and pecking enrichment have been found to be most effective in reducing injuries caused by injurious pecking and elevated structures (e.g. platform or straw bale) were effective in promoting locomotive exercise. </p> <p>    To address some of the gaps in the knowledge regarding the effects of environmental enrichment on turkey behavior, welfare and walking ability, this study examined 1) age-related changes in welfare and gait when turkeys are provided with different types of environmental enrichment; 2) the effects of different types of environmental enrichment on enrichment usage and injurious pecking behavior; 3) specific behaviors and relative location of turkeys when they interact with different types of environmental enrichment.</p> <p>    Data were collected from a total of 420 beak-trimmed tom turkeys housed in 24 littered pens located in two rooms within the same barn. Birds were randomly assigned to six treatment groups with 4 replicate pens per treatment group, including five enrichment groups (straw bale, platform, platform + straw bale, pecking block and tunnel) and a control group (no additional enrichment provided). Welfare measures (wounds on the head, neck, snood, back and tail; beak abnormalities; feather quality; feather cleanliness; and footpad condition) and walking ability (gait) were assessed at 8, 12, 16 and 19 wk. Postmortem footpad condition was assessed at 19 wk. Behavior of turkeys was video recorded at 8, 12 and 16 wk and analyzed using scan sampling. The proportions of turkeys performing target behaviors were determined every 15 min (07:00 h - 22:00 h). Welfare and gait data were analyzed using PROC LOGISTIC with Firth bias-correction. Behavior data were analyzed using PROC GLIMMIX.</p> <p>    Better wing feather quality with age was observed in turkeys in the straw bale and tunnel groups. Footpad condition worsened with age for turkeys in all treatment groups except for the straw bale group. Gait worsened with age in all treatment groups while earlier onset of gait problem was observed in turkeys provided with a tunnel or no enrichment (control group). The average proportion of turkeys using the enrichments declined with age. Turkeys provided with a platform + straw bale had the highest levels of enrichment usage, followed by the platform group. Preening and severe feather pecking behavior did not change with age and were unaffected by the type of enrichment provided. Aggressive pecking and gentle feather pecking were not influenced by the type of enrichment provided. Higher average proportions of turkeys were observed performing environmental pecking in the control group than in the platform + straw bale group. Turkeys’ usage of enrichments mainly included resting on top, locomotion, pecking and remaining under the enrichment when they had access to platforms; resting on top, locomotion and pecking when they had access to straw bales or pecking blocks; and remaining in the tunnel and pecking when they had access to a tunnel.</p> <p>    In conclusion, environmental enrichment showed beneficial effects on turkey wing feather quality, footpad condition and walking ability. Providing tom turkeys with straw bales and tunnels as environmental enrichment can help improve wing feather quality with age and providing straw bales may reduce the development of footpad dermatitis under suboptimal litter conditions. Providing enrichments that can help increase turkey activity and locomotion, including enrichment that can satisfy turkeys’ pecking and foraging needs (straw bale or pecking block) and elevated structures (bale or platform), may be beneficial for turkey walking ability. Multi-functional environmental enrichments, especially a combination of enrichment objects, can promote turkeys’ natural behaviors. Turkeys had the highest enrichment usage when provided with a combination of different enrichment objects (e.g., platform + straw bale) that can serve multiple functions to fulfill their different behavioral needs. Providing a platform only can also achieve high enrichment usage. Turkeys gradually lost interest in interacting with enrichments over time, which may be associated with habituation, destruction of some enrichment objects (e.g. straw bale and pecking block) and fecal contamination on the surface of enrichments. </p> <p>    Future research will be valuable in examining the effects of different types of environmental enrichment in various commercial facilities and across different flocks and seasons. Research is needed to examine the effect of enrichments on turkey activity levels and whether there is a relationship between increased activity level and turkey walking ability. In addition, the effectiveness of making periodic changes to the enrichment objects and using unpredicted schedules of presenting the enrichments on habituation will need to be examined.</p>

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22074号 / 農博第2366号 / 新制||農||1072(附属図書館) / 学位論文||R1||N5228(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 近藤 直, 准教授 小川 雄一, 教授 飯田 訓久 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

<p dir="ltr">Stocking density, space availability, and lameness are important aspects affecting broiler chicken behavior and welfare. Stocking density refers to the weight of broiler chickens per a set area of space typically measured as kg/m2. Space availability is the amount of space per individual broiler chicken typically measured as m2/bird. Stocking density and space availability can contribute to lameness and other aspects of welfare such as footpad dermatitis, hock burn, and feather cleanliness. The behavior of broiler chickens can also be modified by stocking density, space availability, and lameness. All of these aspects are typically related to a change in activity levels which could be used as an indicator of animal welfare. To date, the majority of research that has examined the walking ability of broiler chickens has assessed how stocking density influences the development of gait problems when applied during the grower phase. However, not all broilers develop gait problems at the same point in time and it is unknown whether broilers that initially have sound gait develop gait problems at a similar rate to broilers that are initially classified as having affected gait. Further, the influence of stocking density on the progression of gait abnormalities of broilers with sound and poor gait is unknown. Finally, since space becomes more and more limited as broiler chickens increase in body weight and age, it is unknown how the provision of space during the finisher phase, when broiler chickens are gaining weight rapidly, can influence their walking ability and welfare outcomes. Stocking density is calculated based on projected final weights of broiler chickens from the time they are placed on a commercial farm, and that projected stocking density remains the same from the chick placement date. As stocking densities are increased, there is also an increase in the prevalence of lameness. Age is also known to be related to walking ability, and as broiler chickens age, there is an increase in the prevalence of lameness. While it is known that increasing stocking density and aging are both contributing factors to broiler chicken lameness, there is no previous research on if reducing stocking density at a later age can help alleviate the prevalence of lameness. To address this knowledge gap, two studies were conducted. In the first study, 784 mixed-sex Ross 708 broiler chickens in commercial barns were placed into of four treatment groups. · SOUND: Consisted of broiler chickens that were considered to have sound gait (scores of 0 and 1) and the broilers were housed at farm stocking density (6lb/ft2, 29.29 kg/m2), · AFFECTED: Consisted of broiler chickens that were considered to have affected gait (scores of 2 or higher) and were housed at farm stocking density (6lb/ft2, 29.29 kg/m2) · MIXED-F: Consisted of 50% of broiler chickens that were considered to have sound gait and 50% that were considered to have affected gait and were housed at farm stocking density (6lb/ft2, 29.29 kg/m2) · MIXED-L: Consisted of 50% of broiler chickens that were considered to have sound gait and 50% that were considered to have affected gait and were housed at half of the farm stocking density (3lb/ft2, 14.65 kg/m2) Broiler chickens were randomly selected at 33 days of age from each of four commercial barns for welfare assessments, which included gait scoring to assess walking ability, as well as the assessment of footpad dermatitis and hock burn. Broilers were then assigned to one of two gait categories based on their gait scores. Broilers were either considered to have sound gait meaning they had no or unidentifiable abnormalities, or affected gait meaning there were identifiable abnormalities. To separate treatment groups, custom-built pens (4 ft x 12 ft, 1.22 m x 3.66 m) were constructed. At 37 days of age welfare assessments were conducted again, and then the broiler chickens were placed back into the flock (Chapter 2). The behavior of the broiler chickens was recorded from the evening of day 33 to the morning of day 37 and video was analyzed using scan sampling. The proportion of broiler chickens performing target behaviors was recorded every 10 minutes in the morning (6:00 – 8:00) and evening (19:00 – 21:30). Better gait scores were observed at 37 days of age in broiler chickens in the MIXED-L group and broiler chickens in the SOUND group. The presence of hock burn was lower in broiler chickens in the SOUND group. Cleanliness scores were better for broiler chickens in the MIXED-L group and in broiler chickens in the SOUND. Stocking density impacted the proportion of broilers performing eating, drinking, sitting, and walking (P < 0.05). Walking ability impacted the proportion of broiler chickens standing, walking, and sitting (P < 0.05). To continue investigating the implementation of housing changes later in the broiler chickens’ life, a second study was conducted using 705 mixed-sex Ross 708 broiler chickens. At 7 d, broiler chickens were randomly assigned to 1 of 16 pens (46-47 birds/pen). At 28 d, half of the pens doubled in size after welfare assessments were completed (measuring 8 ft x 10 ft, 3.05 m x 2.44 m, DOUBLE), while the other half remained at the original dimensions (8 ft x 5 ft, 2.44 m x 1.5 m, SINGLE). The DOUBLE pens had an expected stocking density of 15.2 - 15.5 kg/m2 (3.11 - 3.17 lb/ft2) and an estimated space availability of 0.15 to 0.16 m2/bird while the SINGLE pens had an estimated stocking density of 30.4 - 31.1 kg/m2 (6.23-6.37 lb/ft2) and an estimated space availability of 0.07-0.08 m2/bird. Welfare assessments consisting of scoring gait, feather cleanliness and for the presence of FPD and hock burn were conducted at 22 d, 28 d, and 38 d (Chapter 4). At 38 d, broiler chickens in SINGLE pens were less likely to have a score of 0 for FPD (Wald c2 = 15.45, P < 0.0001), hock burn (Wald c2 = 7.26, P = 0.0071), and feather cleanliness (Wald c2 = 11.77, P = 0.0006) than broiler chickens in DOUBLE pens. However, broiler chickens in SINGLE pens were more likely to have a gait score of 0 compared to broiler chickens in DOUBLE pens (Wald c2 = 11.34, P = 0.0008). Broiler chicken behavior was recorded at 23-26 d (Period 1: before space increase), 28-31 d (Period 2: time of space increase), and 36-37 d (Period 3: after space increase). Behavior data were collected using focal sampling for two broiler chickens per each of the 16 pens in the morning, afternoon, and evening (Chapter 5). Broiler chickens housed in double pens had an increased frequency of leg extensions compared to broiler chickens housed in single pens (P < 0.05). Period had a significant impact on the frequency of eating, sitting, and walking and the durations of sitting, environmental pecking, standing, and walking (P < 0.05). Time of day had a significant impact on the frequency of eating, sitting, walking, preening, and leg extensions and the durations of sitting, eating, preening, and standing (P < 0.05). The interaction of age and time of day had a significant impact on the frequency of drinking and leg extensions and the durations of sitting, eating, and walking (P < 0.05). The interaction of age and treatment had a significant impact on the frequency of eating and walking and the duration of preening (P < 0.05). In conclusion, broiler chickens housed in DOUBLE pens did not exhibit a difference in behaviors compared to those in SINGLE pens, other than broilers in the DOUBLE pens performing leg extensions more often. While the first study indicated that having more space available per broiler chicken led to better walking ability, the second study showed the opposite to be true as those with more space had reduced walking ability. This indicates that changing the stocking density through manipulating space in the finisher phase may impact welfare, but further investigation is needed. Future research should first examine the effects of adding space in the finisher phase with 3 treatment groups. While the two discussed here would remain the same, the third group should start with broilers in a pen that is already the size of the DOUBLE pens and remains that way for the entire project. This will ensure that increasing space during the finisher period is beneficial rather than the additional space availability in general accounting for the differences in treatments. All treatment groups should also get fresh bedding with the pen increase to ensure the welfare measurement results are due to the changes in space availability rather than the provision of fresh litter.</p>

<p dir="ltr">The White Pekin duck (<i>Anas platyrhynchos domesticus</i>) is the most widely consumed duck protein in the world. Total duck meat production had a global annual increase of 2.1% per year from 2010 to 2019. The increase in duck meat production can be credited to improved management strategies, nutritional programs, and genetic improvement made to the Pekin ducks by structured breeding programs. Regardless of the advancements already achieved by Pekin duck breeding programs, improvements can still be made. One such improvement that can be made in Pekin duck populations is reducing the frequency of the emerging welfare concern known as flip-over (FO). We hypothesize that egg quality traits, wingspan, back length, and hip width are genetically influenced and their inclusion into Pekin duck breeding programs can be used to improve the Pekin duck. Egg quality traits were collected at weeks of age 30, 32, 35 and 40 on two generations of Pekin duck hens. All heritability estimates and Genetic correlations were calculated using BLUPF90 software, the Restricted Maximum Likelihood (REML) method, and 9,418 individuals in the pedigree. All egg quality traits evaluated are moderate to highly heritable ranging from 0.23 for egg shape to 0.70 for shell ratio. Two hatches of 1,200 Pekin duck hens were assessed at day of age 23 and 30 for wingspan, hip width, and back length using image analysis. Wingspan, hip width, and back length were found to be heritable ranging from 0.04 ± 0.013 to 0.27 ± 0.025 for hip width and back length respectfully. This thesis will discuss approaches to evaluating genetic parameters of egg quality traits in hatching eggs and the possibility of reducing FO through the selection of increased wingspan length.</p>

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京都大学 / 新制・課程博士 / 博士(理学) / 甲第24468号 / 理博第4967号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 Huffman Michael Alan, 教授 古市 剛史, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

The purpose of this dissertation is first to provide an overview of professional competency development and teaching in veterinary education, and then to address the dearth of research in this area by examining students' motivational perceptions of their courses, how these perceptions compare and contrast across courses, and how their perceptions relate to their effort levels and course ratings. Professional competencies encompass cognitive, social, and personal resource skills such as interpersonal communication skills, collaboration, management, promotion of public health, lifelong learning, ethics, diversity competence, and adaptability to changing environments. The inclusion of professional competencies as a requisite portion of the veterinary curriculum has evolved substantially over the past 20 years. In this dissertation, two manuscripts are presented. The first (Chapter 2) is a literature review exploring the past 20 years of professional competency teaching and its development within, and inclusion into, the veterinary curriculum. The first manuscript concludes by describing recommendations from the literature for effective methods of inclusion of professional competencies into the veterinary curriculum. The second manuscript (Chapter 3) details a study conducted in a veterinary college with the aim of determining the extent to which students' motivational perceptions of their courses affect their effort and course ratings in veterinary courses. A second purpose of this study was to identify teaching strategies that can be used to improve the quality of teaching in professional competency courses. Results indicated that perceptions of empowerment, usefulness, and interest have the strongest relationship with effort and course ratings. Based on student responses to open-ended items, suggestions were made that instructors can use to improve student perceptions in their courses as a means to potentially increase student effort levels and overall course ratings. Together, these manuscripts contribute to current motivational theories and offer instructional design ideas to curriculum designers and educators who wish to improve students' motivation and engagement in professional competency development. / Doctor of Philosophy / The overall purpose of this dissertation was to explore student motivation within veterinary education with the goal of identifying ways to improve veterinary courses as well as students' willingness to put effort into their coursework. This study focused primarily on the teaching of professional competencies, which refers to skills in communication, collaboration, management, promotion of public health, lifelong learning, ethics, diversity competence, and adaptability to changing environments. The importance of mastering these skillsets has steadily increased in importance over the past two decades and continues to be an underdeveloped area of many veterinary curricula. There are two manuscripts included in this dissertation. Manuscript 1 (Chapter 2) is a literature review exploring the development of professional competency teaching over the past 20 years and its inclusion into the curriculum at most veterinary colleges. The first manuscript concludes by describing recommendations from the literature for effective methods of inclusion of professional competencies into the veterinary curriculum. Manuscript 2 (Chapter 3) details a study conducted in a veterinary college in which students were surveyed and asked about multiple aspects of their veterinary courses. The purpose of this study was to identify teaching strategies that can be used to improve the quality of teaching in professional competency courses, with the hope of improving students' motivation and effort levels as well. Together, these manuscripts contribute to current motivational theories and offer instructional design ideas to curriculum designers and educators who wish to improve students' motivation and engagement in professional competency development.