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J A Mench

Publications and source records attributed to J A Mench.

At least 19 recordsLinked to original sources
PubMed2006

Differential effects of 4 types of environmental enrichment on aggressive pecking, feather pecking, feather loss, food wastage and productivity in Japanese quail.

1. We examined the effects of 4 types of environmental enrichment (foraging opportunities, structural complexity, sensory stimulation/novelty, and social companionship) on aggressive and feather pecking, feather condition, food wastage, body weight, feed conversion, and egg production in adult Japanese quail. Sex differences were examined where possible. 2. GLM analysis was used to evaluate the effects of enrichment and housing, while test-retest reliability and the stability of measures over 18 d were assessed using partial correlation. 3. Foraging enrichment reduced food wastage. 4. Body weight, feed conversion, and egg production were not affected by enrichment. Rates of aggressive and feather pecking were also not significantly affected, but these behaviours were observed very infrequently in this study. 5. Socially-housed birds had poorer feather condition, lower body weight and less efficient feed conversion than singly-housed birds. Social housing did not affect food wastage. 6. There were not sex differences in feather pecking, feather condition, food wastage, or feed conversion. 7. All measures except feather pecking were reliable over 24 h, but only feather condition and body weight were stable over 18 d. The instability f the behavioural measures over time suggest that enrichment effects may vary with age.

Aggression↗
PubMed2005

Effect of sand and wood-shavings bedding on the behavior of broiler chickens.

The purpose of this study was to determine the effect of 2 different bedding types, sand and wood shavings, on the behavior of broiler chickens. In experiment 1, 6 pens were divided down the center and bedded half with sand and half with wood shavings. Male broilers (10/pen) were observed by scan sampling at 5- or 12-min intervals throughout the 6-wk growth period during the morning (between 0800 to 0900 h), afternoon (1200 to 1500 h), and night (2300 to 0600 h). There was a significant behavior x substrate x week interaction during the day (P < 0.0001) and at night (P < 0.0002). Drinking, dustbathing, preening, and sitting increased in frequency on the sand side but decreased on the wood shavings side during the day, as did resting at night. In general, broilers performed a greater proportion of their total behavioral time budget on the sand (P < 0.0001) as they aged. Broilers used the divider between the 2 bedding types to perch; perching behavior peaked during wk 4. In experiment 2, male broilers were housed in 8 pens (50 birds/pen) bedded only in sand or wood shavings. Bedding type had no effect on behavioral time budgets (P = 0.8946), although there were age-related changes in behavior on both bedding types. These results indicate that when given a choice, broilers increasingly performed many of their behaviors on sand, but if only one bedding type was provided they performed those behaviors with similar frequency on sand or wood shavings.

Aging↗
PubMed2004

Environmental enrichment and development of cage stereotypy in Orange-winged Amazon parrots (Amazona amazonica).

Stereotypies are abnormal repetitive behaviors that often develop in animals housed in impoverished environments. Stereotypy represents the interaction of several complex developmental phenomena. To characterize the temporal nature of stereotypy increase (escalation) and decrease (attenuation), we monitored changes in stereotypy performance in young Orange-winged Amazon parrots reared either in barren cages or cages provided with enrichments designed to facilitate foraging and locomotion. Unenriched parrots developed significantly more stereotypy than enriched parrots, and the mean time to stereotypy onset and the rate and magnitude of stereotypy increase also differed between the two groups. We then provided enrichment to the birds that had been reared in the barren cages. Following a 4-week delay, stereotypy was significantly reduced. These results show that stereotypy can be both prevented and reversed with appropriate environmental modification and illustrate how studying this behavior at many points over time can provide insights into its ontogeny.

Animals↗
PubMed2002

Reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers.

1. The gait scoring system for broilers developed by Kestin et al. (Veterinary Record, 131: 190-194, 1992) has been widely used to evaluate leg problems. The many factors and measures associated with this scale have empirically established its external (biological) validity. However, published test-retest (within-observer) reliabilities are poor, and inter-observer reliabilities are unknown. We evaluated several modifications to this scale aimed at improving its objectivity and reliability. 2. Eighteen naïve observers scored a standardised video of birds exhibiting varying degrees of lameness, either using Kestin et al.'s system, or our modified system. 3. Test-retest reliability (0.906) for Kestin et al.'s system was higher than previously reported. Inter-rater reliability was also good (0.892). The modified system offered significantly better test-retest (0.948) and inter-rater reliabilities (0.943), without incurring costs in terms of time taken or difficulty of use. The systems were consistent, assigning individual birds the same score on average. 4. It is concluded that the modified system offers the advantages of reduced error within and between studies. 5. In a second experiment, we used our modified scoring system to examine the relationship between tibial dyschondroplasia (TD) and gait score in 267 selected broilers. 6. Neither the presence nor severity of TD affected gait score, suggesting that, at least in this strain of broilers, other leg problems like slipped tendons or torsional deformities had more influence on gait impairment than did TD.

Animals↗
PubMed1998

Effect of tryptophan treatment on self-biting and central nervous system serotonin metabolism in rhesus monkeys (Macaca mulatta).

UNLABELLED: Two studies were conducted to examine the effects of oral L-tryptophan (TRP) supplementation as a treatment for self-injurious behavior (SIB) and to investigate behavior and central serotonin turnover of male rhesus monkeys. In Study One, TRP was administered to seven individually housed rhesus monkeys with a recent history of spontaneous SIB. While the monkeys were on TRP treatment (100 mg/kg twice a day), cisternal cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic acid increased markedly (p = .0013) above baseline (baseline mean = 207.6 pmol/ml +/- 39; TRP mean = 320.3 pmol/ml +/- 83.4), and the duration of self-biting behavior decreased below baseline (p = .03). In Study Two, 14 individually housed rhesus monkeys without a history of SIB were placed on three different doses of TRP in random order (50, 100, and 200 mg/kg twice a day). TRP had no effect on any behavioral or biochemical variables in the normal monkeys. CONCLUSIONS: Supplemental tryptophan in well-tolerated doses reduced self-biting and increases serotonin turnover rate in male monkeys with a recent history of SIB. The same doses of TRP do not affect behavior or serotonin metabolism in male monkeys without a history of SIB.

Animals↗
PubMed1998

Elevated plasma corticosterone concentrations influence the onset of rigor mortis and meat color in broilers.

This experiment was conducted to determine the effect of elevated plasma corticosterone (CORT) levels on meat quality characteristics. Male broilers (Arbor Acres) were either 1) fed a diet containing corticosterone (CORT) prior to processing, 2) transported by truck for 3 h before processing, or 3) processed without either of the above treatments. Six crates of birds (10 birds per crate; two crates per treatment) were stunned or killed using CO2 gas. Six birds per crate were processed and blood samples were collected during exsanguination for plasma CORT analysis. Meat samples were collected from carcasses either at 20 min or at 4 h post-mortem. At each sampling time (ST), Pectoralis superficialis samples were collected and either individually quick frozen (IQF) in liquid nitrogen or aged on ice (AOI) for 24 h prior to pH, ratio of inosine to adenosine nucleotides (R-value), cooking loss, shear value, and color analyses. The IQF Biceps femoris samples were used for pH, R-value, color, and heme pigment analysis. Mean (+/- SEM) CORT concentrations were 12.9+/-2.57, 11.7+/-1.38 and 7.9+/-0.79 ng/mL, respectively, in the CORT, transported, and control groups. There were significant treatment by ST (P < 0.05) and ST (P < 0.001) effects on the R-value of IQF P. superficialis samples. The CORT group had the highest L* value (P < 0.01) and the lowest a* value (P < 0.06). There was also a significant main effect of ST on shear values (P < 0.05) of AOI P. superficialis samples, with the means higher at 4 h than at 20 min post-mortem. The R-value of IQF B. femoris samples was markedly influenced by treatment (P < 0.001) and ST (P < 0.001). The results indicate that artificially elevating circulating CORT concentrations results in lighter meat color in broilers.

Animals↗
PubMed1998

Thirty years after Brambell: whither animal welfare science?

It has been just over 30 years since the Brambell Committee issued its clarion call for research on the welfare of animals used in agriculture. What progress has farm animal welfare science made in those 30 years, and what challenges will it face in the next 30? In this article, I discuss the ways in which the Brambell report, with its emphasis on behavioral needs and suffering, both propelled and constrained the development of animal welfare science. The role that economic factors play and the ways in which they have imposed other kinds of constraints on scientists working with farm animals are also mentioned. Despite these constraints, animal welfare science has contributed to a number of significant improvements in the welfare of farm animals. There is, however, a growing sense that animal welfare science has reached an impasse and that ethical and scientific questions about animal welfare have become hopelessly entangled. In this context, I address what I view to be the principal challenge facing farm animal welfare science, namely to move the issue of beyond suffering to an evaluation of broader quality-of-life questions and their application to improvements in welfare.

Journal Article↗
PubMed1997

Shackling of broilers: effects on stress responses and breast meat quality.

1. Experiments were conducted to study the welfare and meat quality effects of shackling. In experiment 1, broilers with or without leg problems were shackled (S) for 4 min on a moving line and blood sampled; or handled (H), returned to the crate and sampled after 4 min; or sampled immediately after removal from the crate (control, C). 2. Plasma corticosterone (CORT) concentrations, as measured by radioimmunoassay, were highest in S and lowest in C, while the H group was intermediate. Leg problems had no effect on CORT. 3. In experiment 2, tonic immobility (TI) was induced in broilers after 2 min inverted handling to determine fear responses. One week later, the birds were fasted, transported and then shackled on a moving shackle line for 0, 1, 3 or 4 min, then unshackled and blood sampled. Wing flapping during shackling was also quantified. 4. Shackling time did not influence CORT concentrations. There was a negative correlation (r = -0.714) between CORT and wing flapping duration in the 1 min shackling treatment. There was no relationship between TI and wing flapping or CORT. 5. In experiment 3, broilers were exposed to two food withdrawal (FW) times (food withdrawn overnight or during crating only) and held for 4 h prior to processing, shackled (0, 2 or 4 min shackling time, ST), and then killed by exsanguination. Blood samples were collected during the neck-cut. Pectoralis superficialis and Supracoracoideus samples were either collected after 15 min and individually quick frozen (IQF) in liquid nitrogen or collected at 4 h post mortem from carcases chilled on slush ice (COI). 6. CORT increased significantly with increased ST. There was a FW x ST interaction effect on the initial pH of fillets. ST influenced the b*, chroma and Hue values of the COI fillets. FW influenced the L* and Hue values of both IQF and COI fillets as well as the a* value of the COI fillets. 7. In summary, CORT increased with shackling time when birds were held after transport. FW and ST also influenced the colour of fillets, although it is not clear whether these changes are perceptible to the consumer. The duration of wing flapping during shackling did not appear to be related to fearfulness, although it was influenced by properties of the shackle line. We suggest that there be a maximum time lapse between shackling and stunning or killing of 2 min to minimise stress and meat quality changes.

Abattoirs↗
PubMed1997

Effects of crating and transport on stress and meat quality characteristics in broilers.

Experiments were conducted to determine 1) whether different crating durations influence stress responses and meat quality in broilers, and 2) whether holding crated broilers after transport influences corticosterone (CORT) levels and meat quality. In a preliminary experiment, male broilers (n = 50) were held in crates (10 birds per crate) for either 0, 1, 2, 3, or 4 h prior to processing. Crating duration did not affect plasma CORT level, cooking loss, shear value of breast or thigh muscles, or carcass skin discolorations. Crating duration also did not affect the color (L*, a*, b*, chroma, and hue angle) of breast meat, but did change the color of thigh meat, with samples from the 3 h crating group having the highest hue values (P < 0.01). Corticosterone concentrations and hue values of thigh samples were positively correlated (P < 0.05, r = 0.244). In Experiment 1, broilers (n = 36) were crated for either 1 or 3 h, with 9 birds per crate. Crating time did not influence plasma CORT, epinephrine, or norepinephrine concentrations, initial pH, color, or texture of breast and thigh meat samples. In Experiment 2, broilers were crated (nine birds per crate) early in the morning and transported 3 h to the processing facility by truck. Nine crates of birds were held in a dark quiet place for 4 h prior to processing (H) and the remaining nine crates were processed immediately (NH). Corticosterone levels were significantly lower (P < 0.01) in the H group than in the NH group. Initial pH of thigh meat of the H group was also significantly lower (P < 0.01), although breast meat pH was not affected by treatment. Holding had no effect on shear values, color (breast and thigh), or total heme concentration (thigh). There was a significant correlation (P < 0.01, r = 0.302) between CORT levels and hue values of thigh meat. These results suggest that higher preslaughter stress levels in broilers could influence the color of thigh meat, although overall meat quality was not affected under the conditions of this study.

Analysis of Variance↗
PubMed1996

Influence of different handling methods and crating periods on plasma corticosterone concentrations in broilers.

1. Experiments were conducted to determine whether different handling methods and crating periods differentially affect plasma corticosterone (CS) concentrations in 6 to 7-week-old broilers. 2. Broilers were subjected to 1 of 3 handling methods for 2 min: (i) 3 birds held in an inverted position in one hand (multiple inverted, MI), (ii) 1 bird held in an inverted position (single inverted, SI), or (iii) upright handling (U), which consisted of holding a bird gently with both hands in an upright position. 3. In experiment 1 birds were returned to their respective pens after handling and in experiment 2 they were crated for up to 4 h after the imposition of handling. In experiment 2 food deprived (FD) and fully fed (FF) uncrated birds were also sampled as controls. Blood samples were collected immediately after handling and at 1-h intervals after handling or handling and crating. 4. In experiment 1, MI and SI birds had higher CS concentrations than U birds. 5. In experiment 2, there were no significant differences in CS concentrations of crated birds despite the different handling treatments. FD birds had higher mean CS concentrations than FF birds, although not as high as those of crated birds. CS concentrations peaked at 3 h after crating. Birds showed predominantly resting behaviour after crating. 6. These results suggest that handling stress can be reduced in broilers by the use of upright handling. However, the methods of handling is not important in influencing CS concentrations if the birds are crated after handling, either because crating is a more potent stressor than handling or due to stressor additivity.

Abattoirs↗
PubMed1996

Decreases in aggression in tryptophan-supplemented broiler breeder males are not due to increases in blood niacin levels.

In previous studies with feed-restricted broiler breeders, it was found that supplementation with dietary Trp decreases aggressive activity more in socially dominant males than in socially subordinate males. Although it is probable that this effect is mediated centrally by serotonin, an alternative possibility is that it is associated with other metabolic products of Trp such as niacin. The objectives of this study were to determine whether 1) supplemental dietary niacinamide decreases aggression in broiler breeder males, 2) elevated blood niacin levels are associated with a decrease in aggression, and 3) social status influences any of these effects on behavior. Using a randomized complete block design, a control (0.19% Trp, 22 mg niacin/kg), Trp (1.5% Trp, 22 mg niacin/kg), or niacinamide (0.19% Trp, supplemented with 140 mg niacinamide/kg) diet was assigned to each pen. There were 16 birds per pen and three pens per treatment. Birds were maintained on skip-a-day feed restriction throughout, and behavioral observations were conducted until the social hierarchy in each pen was determined. Treatment diets were then fed from 15 through 18 wk of age, and the number of aggressive pecks and threats per pen recorded in three 20-min observation periods/wk. Blood samples were collected from dominant and subordinate birds and assayed for niacin using Tetrahymena pyriformis. Supplementing the diet with Trp significantly (P < 0.05) decreased aggression. Niacinamide-treated birds did not differ from either Trp-treated or control-treated birds, and no decreases in aggression were seen in birds with elevated blood niacin levels. Blood levels of niacin were, however, higher in dominant niacin-treated birds than in dominant control birds (P < 0.05), although there were no differences among subordinate or Trp-treated birds. Thus, the modulatory effect of Trp on aggression does not appear to be mediated by increased niacin synthesis.

Aggression↗
PubMed1994

A technique for cannulating the Cisterna magna and sampling cerebrospinal fluid from socially housed birds.

The measurement of central levels of neurochemicals is an important approach to the understanding of the neurophysiological basis of behavior patterns in animals. Previous studies have utilized central sampling techniques developed for individually housed animals. The purpose of this study was to develop a cannulation technique and a method for sampling cerebrospinal fluid (CSF) from socially housed birds to facilitate the study of the neurophysiological basis of social behaviors. The cannulation technique involved the surgical implantation of a 22-gauge concentric guide cannula into the cisterna magna of 16-wk-old, feed-restricted male broiler breeders (n = 6). Individual-specific coordinates and optimum angle and depth of implantation of the cannula were determined in order to place the cannula correctly in the designated site. Once implanted, the guide cannula proved to be unobtrusive and secure and did not attract aggressive pecking from other birds in the pen. Two methods of CSF sampling were then examined. The first method required the use of a push-pull perfusion pump to withdraw CSF at a rate of 1 to 2 microL/min. The second method (passive), which did not use a pump, involved simply removing a "dummy" cannula from the guide cannula to release the CSF, which was then collected with a glass Hamilton syringe. Samples ranging from 100 to 500 microL were collected using the passive method. The combination of the cannulation technique described and the passive sampling method proved to be the most simple, efficient, and reliable method for measuring central levels of neurochemicals in socially housed broiler breeder males.

Animals↗
PubMed1992

Introduction: applied ethology and poultry science.

As a scientific discipline, the study of the biological basis of behavior in animals, ethology, is comparatively new. Ethologists have traditionally conducted primarily observational studies designed to ascertain the evolutionary significance of behaviors in wild animals. There is, however, a growing branch of ethology that is concerned with the application of ethological principles to areas such as the management and welfare of economically important species like poultry. Because of the complexity of the causation and expression of behaviors in animals, it is particularly important that such studies be rigorously designed and analyzed. The purpose of this symposium was to stimulate interest in the study of poultry behavior and welfare, and to provide information about current methodology in ethology.

Animal Welfare↗
PubMed1991

Behavioral and hormonal correlates of social dominance in stable and disrupted groups of male domestic fowl.

An experiment was conducted to determine the behavioral and hormonal correlates of social dominance in stable and disrupted groups of male domestic fowl (Gallus domesticus). In addition, the relative importance of visual and auditory cues in the maintenance of dominance status in this species was assessed. Alpha roosters were removed from their six-bird home pens for 1 week, and placed in either (1) and adjacent pen in visual contact with penmates, (2) and adjacent pen where visual, but not auditory, contact was prevented, or (3) a different building where they were in visual and auditory isolation. Dominance rank, aggressive activity, and crowing frequency were intercorrelated during the premove period. There was a significant increase in both aggression and crowing among the males remaining in the home pen following removal of the alpha male, except in the treatment in which males were still in visual contact with the removed alpha, in which only aggression increased. Increases in crowing frequency were also noted in alpha males. High levels of aggression occurred when alpha males were returned except in those pens in which visual contact had been maintained. Visual cues thus appear to be more important than auditory cues alone with respect to the maintenance of dominant social status in roosters. There were no clear correlations between behavioral variables and plasma androgen or corticosterone levels in either the stable or disrupted flocks, and no consistent changes in the levels of these hormones as a result of experimental manipulation; several possible explanations for this finding are discussed.

Agonistic Behavior↗
PubMed1991

The interaction of dominance status and supplemental tryptophan on aggression in Gallus domesticus males.

In previous studies, we have found that supplemental dietary tryptophan (TRP) decreases aggression in feed-restricted male chickens (Gallus domesticus). The objective of this study was to determine if social status influences the effect which TRP has on aggression. In both experiments, Gallus males were placed on a commercial feed restriction program in which measured amounts of feed are delivered on alternate days beginning at 4 weeks of age. In the first study, birds were fed either 0.19 (control), 0.75 and 1.5% dietary TRP. In the second study, birds were fed either 0.19, 0.38, 0.75 or 1.5% dietary TRP. Dominance hierarchies were linear (p less than 0.05) in all treatment groups as indicated by Landau's indices, which ranged from 0.87 to 0.98. A significant interaction was found between dominance status and supplemental TRP for aggression, with TRP decreasing pecking more in dominant than subordinate birds. In Experiment 1, there were positive correlations (p less than 0.05) between body weight and dominance status in both the control and 0.75% TRP group (p less than 0.05) and no correlation in the 1.5% TRP group. The decrease in aggression by dominant males may have allowed subordinate birds to gain greater access to the feed. Our results indicate that dominant and subordinate males show a differential sensitivity to the effects of dietary TRP, with TRP decreasing pecking more in dominant birds.

Aggression↗
PubMed1991

Behavioral correlates of male mating success in a multisire flock as determined by DNA fingerprinting.

The fertility of an individual rooster within a multi-sire flock may be influenced by a number of behavioral considerations, including frequency and timing of matings and the male's position in the social dominance hierarchy. The relationship between behavior and fertility has proven difficult to assess, however, because there are a limited number of heritable morphological traits that can be used to determine paternity. The objectives of the present study were to use DNA fingerprinting to determine paternity in domestic fowl and to assess some behavioral and physiological correlates of mating success. Sixty day-old chicks from each of two commercial breeds, DeKalb White Leghorn (L) and Warren Color-Sexed (W), were reared in either same-breed or mixed-breed groups. At 43 wk of age, all females and six randomly selected males were mixed into one large pen. Male aggressive and mating behaviors were recorded over a 4-mo period. Fertility of individual sires was determined by DNA fingerprinting and pedigree analysis of chicks. Dominance rank and the frequencies of both completed matings and mating attempts were positively correlated with fertility (P less than .01). In addition, wing flapping was correlated with both dominance (P less than .001) and fertility (P less than .05). There was no correlation between fertility and plasma testosterone. There were breed effects on dominance status, with W dominating L. Multiple paternity was demonstrated in 4 out of 10 families by DNA fingerprinting. The present study is the first one to demonstrate a correlation between dominance and fertility in a flock containing several males of the same breed and morphology.

Animals↗
PubMed1991

Research note: feed restriction in broiler breeders causes a persistent elevation in corticosterone secretion that is modulated by dietary tryptophan.

The corticosterone response of immature broiler breeder males to feed restriction and the administration of increased levels of dietary Trp was investigated. Corticosterone levels were significantly (P less than .01) higher in birds placed on a skip-a-day (SD) feed restriction regimen from 4 to 15 wk of age than in birds fed an ad libitum intake. Elevated levels in SD birds persisted for the duration of the study. Levels were also higher in SD birds on those days on which feed was withheld (FEED-OFF) than on those days on which feed was delivered (FEED-ON). The SD males consuming a diet containing 1.5% Trp showed a change in the pattern of hormone secretion as compared with SD control birds (.19% Trp), with corticosterone levels increasing on the FEED-ON days and decreasing on the FEED-OFF days. It is concluded that SD feed restriction causes a persistent elevation of plasma corticosterone in broiler breeders. The secretory pattern of corticosterone can be modulated by increasing the Trp content of the diet, possibly as a result of reciprocal interactions between the serotonergic system and the hypothalamic-pituitary-adrenal axis.

Animals↗