Mutation in bovine beta-carotene oxygenase 2 affects milk color.

beta-Carotene biochemistry is a fundamental process in mammalian biology. Aberrations either through malnutrition or potentially through genetic variation may lead to vitamin A deficiency, which is a substantial public health burden. In addition, understanding the genetic regulation of this process may enable bovine improvement. While many bovine QTL have been reported, few of the causative genes and mutations have been identified. We discovered a QTL for milk beta-carotene and subsequently identified a premature stop codon in bovine beta-carotene oxygenase 2 (BCO2), which also affects serum beta-carotene content. The BCO2 enzyme is thereby identified as a key regulator of beta-carotene metabolism.

The effects of a perch, dust bath, and nest box, either alone or in combination as used in furnished cages, on the welfare of laying hens.

This experiment examined the welfare-related effects of individual furniture items alone or in combination in a factorial experiment using Hy-Line Brown hens housed in 8-bird furnished cages. Welfare was assessed during two 8-wk sampling periods commencing at 29 and 59 wk of age. Measurement of stress, immunology, feather, foot and claw condition, and behavior were taken, and bone strength was measured at the end of the experiment. With the exception of the positive effects of a perch on bone strength, any effects of furniture items were relatively small, even though the furniture was extensively used. Although there were changes in behavior and small changes in feather, foot, and claw condition, it is unclear whether these changes have any meaningful implications for welfare. In this experiment there were 2 additional external control treatments for a small study that examined the effects of increasing space per bird (8 birds in single- and double-width cages) and the effects of group size (8 and 16 birds in double-width cages); using similar methodologies, these treatments showed differences in egg corticosterone concentrations and evidence of immunosuppression. Together, these data suggest that although furniture when present was well-used, any effects of furniture on hen welfare measured by physical and physiological traits, other than the benefit of a perch on bone strength, were smaller than effects of group size and space allowance.

Gene expression and cellular content of cathepsin D in Alzheimer's disease brain: evidence for early up-regulation of the endosomal-lysosomal system.

In Alzheimer's disease brains, more than 90% of pyramidal neurons in lamina V and 70% in lamina III displayed 2- to 5-fold elevated levels of cathepsin D (Cat D) mRNA by in situ hybridization compared with neurologically normal controls. Most of these cells appeared histologically normal. The less vulnerable nonpyramidal neuron population in lamina IV had relatively normal message levels. Neuronal populations expressing more Cat D mRNA also displayed quantitatively increased Cat D immunoreactive protein. Cat D mRNA expression was only moderately increased in astrocytes. Degenerating neurons exhibited intense immunoreactivity but lowered Cat D mRNA levels. The upregulation of Cat D synthesis and accumulation of hydrolase-laden lysosomes indicate an early activation of the endosomal-lysosomal system in vulnerable neuronal populations, possibly reflecting early regenerative or repair processes. These abnormalities also represent a basis for altered regulation of amyloid precursor protein processing.

Behavioural responses of poultry during kosher slaughter and their implications for the birds' welfare.

Measurements were made during Shechita (kosher) slaughter of 692 meat chickens, including the behaviour of the birds during the procedure and the times from their removal from the crate, to neck cutting, bleed-out and shackling. Four of 100 birds showed a mild physical response to neck cutting but the others showed no response. Approximately 60 per cent of the birds showed a physical response to touching the eye or eyelid at up to 5 seconds after neck cutting, but by 15 seconds none showed this response. The birds became unable to retain their posture and suffered involuntary muscular contractions at 12 to 15 seconds after neck cutting and had lost approximately 40 per cent of their total blood volume by 30 seconds after neck cutting.

High-molecular-weight hydroxypropylmethylcellulose. A cholesterol-lowering agent.

BACKGROUND: We assessed the efficacy of a high-molecular-weight hydroxypropylmethylcellulose (K8515) as a cholesterol-lowering agent, the dose-response profile of its action, and the ability of adult subjects to tolerate its ingestion at effective doses. METHODS: These studies were conducted at the Clinical Research Center of The University of Michigan Hospitals, Ann Arbor. Efficacy was assessed in 10 normal and 12 mildly hyperlipidemic subjects in double-blind, randomized crossover trials of 1 and 2 weeks' duration, respectively. The dose-response profile was studied in 12 mildly hypercholesterolemic subjects in a nonrandomized control trial with doses given in escalating order. Tolerance was assessed by a questionnaire of adverse effects and bowel movement habits in all subjects. RESULTS: We found that 10 g of K8515 ingested in a prehydrated form three times a day with meals lowered total cholesterol levels by an average of 1.45 mmol/L (56 mg/dL) (32%) in normal subjects within 1 week. In two studies in subjects with mildly elevated cholesterol levels (with entry levels ranging from 5.35 mmol/L [207 mg/dL] to 6.70 mmol/L [260 mg/dL]), average reductions of 1.00 mmol/L (39 mg/dL) (18%) and 1.15 mmol/L (45 mg/dL) (20%) were observed within the same period. The effect was primarily due to a reduction in low-density lipoprotein cholesterol levels. Low-density lipoprotein levels in normal subjects were an average of 1.10 mmol/L (42 mg/dL) (38%) lower after a week of 10 g of K8515 three times a day with meals, and in the two studies in subjects with mild hyperlipidemia, the reductions in low-density lipoprotein levels after 1 week were 0.95 mmol/L (37 mg/dL) (23%) and 1.05 mmol/L (40 mg/dL) (25%). Although there was a tendency for high-density lipoprotein cholesterol levels to decrease, this was significant only in normal subjects. Decreases in cholesterol levels were not accompanied by any rise in triglyceride levels. Dose-response studies in those with mildly elevated cholesterol levels indicated that it is possible to achieve a 15% decrease in low-density lipoprotein cholesterol levels within 1 week at a dose of 6.7 g three times a day, with minimal adverse effects. CONCLUSION: These results suggest a role for high-molecular-weight hydroxypropylmethylcellulose in the clinical treatment of mild hypercholesterolemia.

Colocalization of lysosomal hydrolase and beta-amyloid in diffuse plaques of the cerebellum and striatum in Alzheimer's disease and Down's syndrome.

The lysosomal hydrolases, cathepsin D (Cat D) and beta-hexosaminidase A (HEX), which are normally intracellular enzymes, colocalize with beta-amyloid in a subgroup of diffuse plaques in the cerebellum and striatum of individuals with Alzheimer's disease or Down's syndrome. Using specific antisera in combination with single- and double-label immunocytochemical techniques, extracellular hydrolase was detected in 30 to 40% of the diffuse plaques in the cerebellar molecular layer and nearly all of the diffuse plaques in the striatum. In both Alzheimer's disease and Down's syndrome, about 5 to 10% of the cerebellar Purkinje cells contained abnormally increased numbers of hydrolase-positive lysosomes despite their normal appearance by conventional histologic stains. Occasional atrophic Purkinje cells identified by Nissl stain were intensely immunostained. By confocal imaging analysis, abnormal hydrolase-laden Purkinje cell dendrites were seen coursing through some hydrolase-positive plaques and were continuous with dendritic branches that terminated within deposits of extracellular hydrolase and beta-amyloid. In the striatum, intensely immunostained abnormal-appearing neurons were commonly associated with extracellular deposits of hydrolase immunoreactivity and beta-amyloid within diffuse plaques and in the less commonly seen classical plaques. In both brain regions, other hydrolase-negative beta-amyloid deposits were seen, these being associated with blood vessels. The presence of HEX immunoreactivity in neurons, but not in glia, and its abundance in plaques support earlier studies, suggesting that neurons are the principal source of plaque hydrolase. An endosomal-lysosomal system upregulation, with increased hydrolase expression and extracellular enzyme deposition in plaques, is, like beta-amyloid deposition, an early marker of metabolic dysfunction potentially related to primary etiologic events in Alzheimer's disease and Down's syndrome.

Candida hepatitis. Histopathologic diagnosis.

Candida hepatitis, usually a manifestation of disseminated candidiasis in immunocompromised patients, is difficult to diagnose antemortem. We studied six patients with proven hepatic candidiasis to assess features helpful in deriving a correct diagnosis. Five patients were immunosuppressed as a result for treatment for leukemia; one was immunosuppressed due to renal transplantation. All had sustained fevers greater than 101 degrees F, elevated alkaline phosphatase levels, and multiple hepatic and splenic defects--presumably abscesses--on abdominal CT scan. Twelve liver biopsies (nine needle, three wedge) were examined. Biopsies from four patients contained identifiable Candida organisms within suppurative granulomas; a biopsy from a fifth patient grew Candida albicans in cultures. In the sixth patient, the first biopsy was culture positive for Candida albicans, and the second biopsy, a fine-needle aspirate, contained Candida organisms and purulent material. In all of the nondiagnostic biopsies, as well as in regions of the diagnostic biopsies around the suppurative granulomas, mass-associated obstructive changes were noted. These included pericentral sinusoidal dilatation and cholestatic inflammation characterized by periportal ductular proliferation with surrounding neutrophils and edema. We conclude that in the appropriate clinical setting, these mass-associated histologic findings are suggestive of adjacent Candida abscesses. Definite diagnosis requires either the identification of Candida organisms within inflammatory hepatic lesions or positive culture of Candida from the liver biopsy.

The clinical significance of focal active colitis.

Focal crypt injury by neutrophils (cryptitis/crypt abscesses), or focal active colitis (FAC), is a common isolated finding in endoscopic colorectal biopsies. Focal active colitis is often thought of as a feature of Crohn's disease, but may also be seen in ischemia, infections, partially treated ulcerative colitis, and as an isolated finding in patients undergoing endoscopy to exclude neoplasia. Clinical, endoscopic, and pathological data were retrospectively reviewed from 49 patients with focal active colitis, who had no other diagnostic findings on colorectal biopsy and no history of chronic inflammatory bowel disease. The histological findings were correlated with clinical diagnoses. Follow-up information was available for 42 of 49 focal active colitis patients. None developed inflammatory bowel disease; however, 19 patients had an acute self-limited colitis-like diarrheal illness, 11 had incidental focal active colitis (patients without diarrhea that were endoscoped to exclude colonic neoplasia and found to have asymptomatic FAC), 6 had irritable bowel syndrome, 4 had antibiotic-associated colitis, and 2 had ischemic colitis. Twenty patients were immunosuppressed, and 19 were taking nonsteroidal anti-inflammatory drugs. No histological features predicted final diagnoses. FAC did not predict the development of chronic colitis, even when mild crypt distortion or slight basal plasmacytosis was present. The preponderance of acute self-limited colitis and antibiotic-associated colitis among the FAC patients, along with the high number of immunosuppressed patients, support the conclusion that most FAC cases are infectious. The incidental detection of FAC in patients undergoing endoscopy to exclude colonic neoplasia was not clinically significant. The role of nonsteroidal anti-inflammatory drugs in FAC deserves further study.

Pupillary and electroretinographic abnormalities in a family with neuronal intranuclear hyaline inclusion disease.

Abnormal pupillary function and a severely depressed electroretinogram were found in four members of a family with neuronal intranuclear hyaline inclusion disease, an idiopathic degenerative disorder that involves the central and peripheral nervous systems. Symptoms were limited to the gastrointestinal system and consisted principally of abdominal pain, constipation, and severe weight loss. The discovery of light-fixed pupils in the propositus led to the first antemortem diagnosis by rectal biopsy in two generations of this family. Abnormalities of gastrointestinal motility and pupillary reactions constituted the only objective evidence of autonomic dysfunction; the abnormal electroretinogram was the only evidence of central nervous system dysfunction.

Electrogastrography: a document prepared by the gastric section of the American Motility Society Clinical GI Motility Testing Task Force.

The objective of this document is to present the consensus opinion of the American Motility Society Clinical GI Motility Testing Task Force on the performance and clinical utility of electrogastrography (EGG). EGG is a non-invasive means of recording human gastric myoelectrical activity or slow waves from cutaneous leads placed over the stomach. In healthy volunteers, EGG tracings exhibit sinusoidal waveforms with a predominant frequency of 3 cycles per minute (cpm). Clinical studies have shown good correlation of these cutaneous recordings with those acquired from serosally implanted electrodes. The amplitude of the EGG waveform increases with ingestion of caloric or non-caloric meals. Some patients with nausea, vomiting, or other dyspeptic symptoms exhibit EGG rhythm disturbances or blunting of meal-evoked EGG signal amplitude increases. These abnormalities correlate to some degree with delayed gastric emptying of solids. In selected patients, EGG may be complementary to gastric emptying testing. To date, no therapies have convincingly demonstrated in controlled studies that correcting abnormalities detected by EGG improves upper gastrointestinal symptoms. Proposed clinical indications for performance of EGG in patients with unexplained nausea, vomiting and dyspeptic symptoms must be validated by prospective controlled investigations.

High viscosity hydroxypropylmethylcellulose reduces postprandial blood glucose concentrations in NIDDM patients.

The ability of high viscosity hydroxypropylmethylcellulose (HPMC) to reduce postprandial glucose concentrations was assessed in patients with non-insulin-dependent diabetes (NIDDM) and healthy volunteers. The study design consisted of a two-way crossover, single-dose administration of 10 g prehydrated high viscosity HPMC, or placebo, with a standard carbohydrate-rich meal. In patients with NIDDM, HPMC reduced blood glucose concentrations at the 60-, 75-, 90-, 120- and 150-min sampling intervals, with an average reduction in the maximum postprandial blood glucose concentration, Cmax, of 24% (P < 0.05). The time at which the maximum concentration was reached, Tmax, remained unchanged. The area under the blood concentration versus time plot, AUC0-6h, was reduced by an average of 15% (P < 0.05). The blood concentration profile of insulin followed that of glucose. Concentrations were significantly lower than in the placebo phase only at the 120-min sampling time, while pharmacokinetic parameters (Cmax, Tmax and AUC0-6h) were unchanged. These results suggest that alterations in the blood glucose profile are mediated by luminal events rather than by changes in hormonal response. In contrast to the NIDDM patients, neither the pharmacokinetic parameters nor the blood glucose concentrations at specific sampling times were significantly affected by the co-administration of HPMC in healthy volunteers. Overall, the results of this study suggest that HPMC may be a useful adjunct in the management of NIDDM.

Effect of intragastric pH on the absorption of oral zinc acetate and zinc oxide in young healthy volunteers.

BACKGROUND: Zinc is an important nutrient and is necessary to maintain a multitude of physiologic processes. Mineral supplements that provide physiologic doses of zinc may be used when dietary zinc is inadequate. Zinc is also used in pharmacologic doses to treat zinc deficiency and diseases such as Wilson's disease and acrodermatitis enteropathica. Although there are several zinc salts available, they are not equal in solubility, which is thought to be a key factor in zinc absorption. Moreover, the solubility of the salts is affected by pH, which may vary between pH 1 and 7 under various physiologic conditions in the stomach. The objectives of this 2-way 4-phase crossover study were to evaluate the effect of high (> or = 5) and low (< or = 3) intragastric pH on the absorption of zinc from the acetate and oxide salt in young healthy volunteers. METHODS: After a 9-hour fast, 10 healthy subjects (5 males and 5 females) were given a single oral dose of 50 mg of elemental zinc as the acetate or the oxide salt and under either high or low intragastric pH conditions. In all phases, a Heidelberg capsule pH detector-transmitter was used to continuously monitor intragastric pH. During the high pH phases, single oral doses of famotidine 40 mg oral suspension were administered before the zinc to raise the intragastric pH above 5. Intragastric pH < or = 3 was maintained in the low pH phases. RESULTS: The mean plasma zinc area under the curve for zinc acetate at low pH (AL), zinc acetate at high pH (AH), zinc oxide at low pH (OL), and zinc oxide at high pH (OH) were 524, 378, 364, and 66 micrograms x h/dL, respectively. The highest zinc plasma concentrations occurred with the acetate salt at a low intragastric pH, while the lowest plasma concentrations occurred with the oxide salt at a high intragastric pH. The importance of pH to the dissolution of these salts was verified by in vitro tests. Twenty-four-hour urinary zinc excretion was the highest for the AL phase and lowest for the OH phase. CONCLUSION: This study indicates that intragastric pH and salt solubility-dissolution are important in the oral absorption of zinc. Specifically, the oxide salt is not an appropriate zinc salt to use in those patients with elevated intragastric pH.

Novel method to assess gastric emptying in humans: the Pellet Gastric Emptying Test.

To further validate the Pellet Gastric Emptying Test (PGET) as a marker of gastric emptying, a randomized, four-way crossover study was conducted with 12 healthy subjects. The study consisted of oral co-administration of enteric coated caffeine (CAFF) and acetaminophen (APAP) pellets in four treatment phases: Same Size (100 kcal), Fasted, Small Liquid Meal (100 kcal), and Standard Meal (847 kcal). The time of first appearance of measurable drug marker in plasma, t(initial), was taken as the emptying time for the markers. Co-administration of same size enteric coated pellets of CAFF and APAP (0.7 mm in diameter) revealed no statistically significant differences in t(initial) values indicating that emptying was dependent only on size and not on chemical make-up of the pellets. Co-administration of different size pellets indicated that the smaller 0.7-mm diameter (CAFF) pellets were emptied and absorbed significantly earlier than the larger 3.6-mm diameter (APAP) pellets with both the Small Liquid Meal (by 35 min) and the Standard Meal (by 33 min) (P<0.05). The differences in emptying of the pellets were not significant in the Fasted Phase. The results suggest that the pellet gastric emptying test could prove useful in monitoring changes in transit times in the fasted and fed states and their impact on drug absorption.

Injection sclerotherapy-induced esophageal strictures. Risk factors and prognosis.

Injection sclerotherapy (IS) has become an effective modality for the treatment of bleeding esophageal varices. Despite improvements in equipment, sclerosant solutions and operator technique, injection sclerotherapy-induced esophageal strictures (ISES) remain a significant cause of patient morbidity. To analyze the risk factors and prognosis of ISES, the records of 117 patients who underwent IS over a 6-year period at a single teaching institute were reviewed. The predictive value of multiple risk factors including the patient's age, Child's risk classification, previous bleeding episodes, etiology of varices, cumulative amount of sclerosant used, and the number of IS treatments were determined using ANOVA. A P value of less than 0.05 was considered significant. In all cases, a free-hand injection technique, flexible endoscopes and sodium morrhuate were used. During a mean follow-up period of 228 days (1-1,469 days), 41 patients (35%) died and 24 patients (20.5%) developed symptomatic strictures. The cumulative amount of sclerosant used (81.4 +/- 9.5 ml) and the number of IS treatments (6.5 +/- 0.7) required in the stricture group was significantly greater than in the nonstricture group (49.1 +/- 2.7 and 4.0 +/- 0.3, respectively). The risk of stricture formation did not correlate with the volume of sclerosant injected per treatment, cause of varices, number of previous bleeds, or Child's hepatic risk class. A mean of 3.6 +/- 4.5 dilations was required for treatment of established strictures and 18 patients (75%) required r 4 dilations. One esophageal perforation occurred following dilation. Mortality correlated with hepatic risk class as 30/41 (73%) of deaths occurred in Child's C patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Sources of sampling variation in saliva cortisol in dogs.

The main advantage of collecting saliva cortisol as opposed to plasma cortisol is that it is non-invasive and therefore it is now widely used in stress measurement studies on farm animals and dogs. Although a plasma cortisol response to handling associated with blood collection generally occurs at 3 min from the commencement of handling, there is no information in the literature on the time course of the response of salivary cortisol concentration to handling. The aims of these experiments were to (1). determine if there is a response to up to 4 min handling that affects cortisol concentration in saliva and (2). determine the main causes of variation in saliva cortisol in dogs over time. In experiment 1, saliva was collected from six Kelpies at 0 min then 2, 3 or 4 min after the commencement of restraint. There was no handling effect found in up to 4 min sampling time. In experiment 2, saliva was collected from six Labrador Retrievers five times in 2 h (14:00-16:00), three days a week for four weeks. Some of the sources of variation in saliva cortisol over time included between dog variation that varied over a period of days and variation between occasions that affected the group of dogs as a whole.

Relationships between human-animal interactions and productivity of commercial dairy cows.

This study examined the relationships between a number of stockperson and cow variables at 66 commercial dairy farms. Variables such as the attitudes and behavior of stockpeople toward their cows and the behavioral response to humans and productivity of cows were studied over one lactation. There were consistent and significant correlations between some of these stockperson and cow variables. For example, a positive attitude by stockpeople toward the behavior of dairy cows was negatively correlated with the number of forceful, negative, tactile interactions used by stockpeople in handling cows (r = -0.27, df = 127, P < 0.01). Furthermore, based on farm averages, the number of forceful, negative, tactile interactions used by stockpeople was negatively correlated with the percentage of cows approaching within 1 m of an experimenter in a standard test (r = -0.27, df= 64, P< 0.05). Although not confirming a fear-productivity relationship, a moderate but nonsignificant correlation was found between flight distance of cows to an experimenter in a standard test and milk yield (r = -0.27, df = 33, P > 0.05). Support for the existence of a negative fear-productivity relationship was the finding that the use of negative interactions by stockpeople was significantly and negatively correlated with milk yield, protein, and fat at the farm (r = -0.36, -0.35 and -0.33, respectively, df = 64, P < 0.01) and was significantly and positively correlated with milk cortisol concentrations at the farm (r = 0.34, df= 64, P < 0.01). Furthermore, the percentage of cows approaching within 3 m of an experimenter in a standard test was positively correlated with conception rate to the first insemination (r = 0.38, df = 46, P < 0.01). The significant correlations found in the present study between stockperson attitudes and behavior and cow behavior and productivity, although not evidence of causal relationships, indicate the possibility of targeting these human characteristics to reduce fear responses of dairy cows to humans and improve the cows' productivity.

The effect of breeding facility and sexual stimulation on plasma cortisol in boars.

Nine boars were used to evaluate effects of breeding facility design and sexual activity on plasma cortisol concentrations . In one breeding facility (conventional), boars were housed individually in small pens, and female pigs were mated in those boar pens. In another breeding facility (Detection-Mating Area [DMA] system), boars were housed individually in stalls, and female pigs were mated in a specific mating pen adjacent to the front of stalls where boars were housed. After 51 d of housing treatment, a catheter was surgically implanted in the cephalic vein for collection of blood samples. Daytime profiles (hourly collections from 0900 to 1700) of cortisol did not differ among boars in the two treatment groups. Cortisol was greater (P < .01) in the morning than in the afternoon. Administration of ACTH increased (P < .001) plasma cortisol in boars, but breeding facility did not affect the ACTH-induced changes in cortisol concentrations. There was a treatment x time interaction (P < .02) for cortisol after sexual stimulation, and the magnitude and duration of increase in cortisol were greater (P < .05) in the DMA treatment group. Cortisol was greater (P < .001) after than before mating for both treatment groups. An acute increase in plasma cortisol concentration in boars seems to be a normal biological response to sexual activity. However, magnitude and duration of the increase in cortisol may be influenced by breeding facility design and mating procedure. There is no evidence, based on physiological data, that housing boars in stalls in the DMA system has any adverse effects on their welfare.

The effects of cognitive behavioral intervention on the attitude and behavior of stockpersons and the behavior and productivity of commercial dairy cows.

Two experiments, one involving 29 commercial farms and the other involving 94 commercial farms, were conducted to examine the effects of a training program targeting a number of attitudinal and behavioral variables in stockpeople. These stockperson variables had been previously shown to be related to fear of humans and productivity of commercial cows. In both experiments, two treatments were imposed: an Intervention treatment, consisting of a cognitive-behavioral intervention procedure designed to improve the attitude and behavior of stockpeople toward cows, and a Control treatment, in which no intervention was attempted. In Exp. 1, an analysis of covariance, using previous lactation variables as the covariate, revealed effects of the Intervention treatment on the attitude and behavior of the stockpeople and the behavior of cows. Stockpeople at Intervention farms showed more (P < 0.01) positive beliefs about handling cows and used a lower (P < 0.05) number and percentage of negative tactile interactions in handling cows than stockpeople at the Control farms. Cows at the Intervention farms showed a shorter (P < 0.05) flight distance to humans, indicating a lower level of fear of humans by these cows. However, 36% of the Intervention farms failed to show a reduction in average flight distance over the two lactations. Although there was no significant treatment effect on milk yield, the Intervention farms in which fear levels declined following the intervention had a higher (P < 0.05) milk yield than the other farms. In Exp. 2, a significant (P < 0.05) increase was found in the milk yield of cows following the Intervention treatment. Similar treatment effects were observed on both milk protein and milk fat. These results indicate that cognitive-behavioral interventions that successfully target the key attitudes and behavior of stockpeople that regulate the cow's fear of humans offer the industry good opportunities to improve the productivity of cows.

Human-animal interactions.

The objective of this article is to discuss the human-animal relationship in animal production, emphasizing the importance of this relationship to the productivity and welfare of the animal, some of the factors that may regulate the relationship, and how to manipulate this relationship to improve the productivity and welfare of the animal.

Science and its application in assessing the welfare of laying hens in the egg industry.

OBJECTIVE: To provide a rational framework for the scientific assessment of welfare and to use this framework to assess the welfare implications of issues relevant to the Australian egg industry. PROCEDURE: A well-accepted approach to the assessment of animal welfare, based on assessing how well the animal is adapting, is described. This approach is used to consider the welfare implications of issues such as space, perches, nest boxes, dust baths, abrasive strips and non-cage housing systems. CONCLUSIONS: The role of science in the welfare debate is to provide biological facts and thus it is important to separate welfare and ethics. The welfare of an animal in response to a housing system or husbandry procedure can be assessed by evaluating how much has to be done by the animal in order to cope and the extent to which the coping attempts are succeeding. Using this approach there is evidence for improved welfare from increasing space in cages, based on reduced aggression, corticosterone concentrations and mortalities and increased production, and for incorporating perches, based on the reduction in injuries at depopulation. Similar evidence for the inclusion of dust baths and nest boxes is lacking. The data on abrasive strips are equivocal with recommendations from overseas for their inclusion, whereas some local data have shown an increase in mortality can occur. Similarly, the data on non-cage systems are equivocal. The data on bone strength suggest improved fitness in non-cage systems, the data on stress suggest fitness may be better, similar or worse in non-cage systems, and the limited data on immunology suggest fitness may be worse in non-cage systems than in conventional cages.