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Objective: To compare the propofol infusion rate and cardiopulmonary effects during total intravenous anesthesia with propofol alone and propofol combined with methadone, fentanyl or nalbuphine in domestic chickens undergoing ulna osteotomy., Study Design: Prospective, randomized, experiment trial., Animals: A total of 59 healthy Hissex Brown chickens weighing 1.5 ± 0.2 kg., Methods: Anesthesia was induced with propofol (9 mg kg -1 ) administered intravenously (IV) and maintained with propofol (1.2 mg kg -1 minute -1 ) for 30 minutes. Birds were intubated and supplemented with 100% oxygen through a nonrebreathing circuit under spontaneous ventilation. Thereafter, each animal was randomly assigned to one of four groups: group P, no treatment; group PM, methadone (6 mg kg -1 ) intramuscularly (IM); group PN, nalbuphine IM (12.5 mg kg -1 ); and group PF, fentanyl IV (30 μg kg -1 loading dose, 30 μg kg -1 hour -1 constant rate infusion). During the osteotomy surgery, the propofol infusion rate was adjusted to avoid movement of birds and provide adequate anesthesia. Pulse rate, invasive blood pressure, respiratory frequency, end-tidal carbon dioxide partial pressure (Pe'CO 2 ) and hemoglobin oxygen saturation (SpO 2 ) were recorded., Results: Data were available from 58 chickens. The mean ± standard deviation propofol infusion rate (mg kg -1 minute -1 ) for the duration of anesthesia was: group P, 0.81 ± 0.15; group PM, 0.66 ± 0.11; group PN, 0.60 ± 0.14; and group PF, 0.80 ± 0.07. Significant differences were P versus PM (p = 0.042), P versus PN (p = 0.002) and PF versus PN (p = 0.004). Pulse rate, blood pressure and SpO 2 remained acceptable for anesthetized birds with minor differences among groups. Values of Pe'CO 2 >60 mmHg (8 kPa) were observed in all groups., Conclusions and Clinical Relevance: Methadone and nalbuphine, but not fentanyl, decreased the propofol infusion rate required for anesthesia maintenance, but resulted in no obvious benefit in physiological variables., (Copyright © 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

In avian species, maternal immunoglobulin Y (IgY) is transferred from the blood to the yolks of maturing oocytes; however, the mechanism underlying this transfer is unknown. To gain insight into the mechanisms of maternal IgY transfer into egg yolks, IgY-depleted chickens were generated by removing the bursa of Fabricius (bursectomy) during egg incubation, and their egg production and IgY transport ability into egg yolks were determined. After hatching, blood IgY concentrations of the bursectomized chickens decreased gradually until sexual maturity, whereas those of IgA remained low from an early stage of growth (from at least 2 wk of age). Chickens identified as depleted in IgY through screening of blood IgY and IgA concentrations were raised to sexual maturity. At 20 wk of age, both blood and egg yolk IgY concentrations in the IgY-depleted group were 600-fold lower than those of the control group, whereas egg production did not differ between the groups. Intravenously injected, digoxigenin-labeled IgY uptake into the egg yolk was approximately 2-fold higher in the IgY-depleted chickens than in the controls, suggesting that IgY depletion may enhance IgY uptake in maturing oocytes. DNA microarray analysis of the germinal disc, including the oocyte nucleus, revealed that the expression levels of 73 genes were upregulated more than 1.5-fold in the IgY-depleted group, although we could not identify a convincing candidate gene for the IgY receptor. In conclusion, we successfully raised IgY-depleted chickens presenting a marked reduction in egg yolk IgY. The enhanced uptake of injected IgY into the egg yolks of the IgY-depleted chickens supports the existence of a selective IgY transport mechanism in maturing oocytes and ovarian follicles in avian species., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

This work aims to study an alternative technique of cecectomy in roosters using inhalation anesthesia for subsequent use in digestibility experiments. A total of 30 adult chickens of Leghorn breed were used with an average age of 27 wk. The birds were preoxygenated, and the anesthetic induction was performed using isoflurane diluted in oxygen. After proper muscle relaxation, endotracheal intubation was performed using a Murphy catheter and kept in anesthesia under mechanical ventilation with a constant monitoring of electrocardiography variables, heart rate, oxyhemoglobin saturation, and body temperature during the surgical procedure. An incision of approximately 3 cm was made between keel and cloaca in order to expose and extirpate the cecum followed by a simple ligature. The opening of the peritoneal cavity was closed in 2 ways: Sultan suture technique was used for closing the abdominal wall and modified Cushing intradermic continuous points for closing the skin. The time for anesthesia induction and preoperational period noted to be 10 ± 2 min. Surgical procedures completed in 7 ± 1.5 min. No intraoperatively and postoperatively harm observed in animals. Water was immediately provided after the birds returned to cages and feed offered after 24 h of surgery. In remaining birds, no abnormalities were observed during and after the experimental period (3 mo). The present study describes a promising update on cecectomy technique regarding anesthesia induction and surgical procedures in roosters using potential drugs and safer surgical materials without any trans- and postoperative complications., (© 2019 Poultry Science Association Inc.)

Five 48-h precision-fed rooster assays were conducted with the objective to determine true metabolizable energy (TMEn) using conventional roosters and/or standardized amino acid digestibility using cecectomized roosters for distillers dried grains with solubles (DDGS) produced from human food waste at high solids content (FWDDGS), DDGS produced from 4 corn hybrids with increases in grain protein concentration or the concentrations of several dietary indispensable amino acids, and a coproduct that is produced by a process which separates a high protein and yeast fraction from ethanol stillage (Still Pro, Fluid Quip Process Technologies, Cedar Rapids, IA). These results from the first cecectomized rooster assay indicated that the standardized digestibility values for Lys, Met, Cys, Thr, and Val were 61, 75, 70, 70, and 72%, respectively. Using conventional roosters, the TMEn for the FWDDGS was 3,890 kcal/kg DM. The DDGS produced from the high protein mutant corn hybrid had a higher protein content of 34% compared with 28% protein for DDGS from the control corn hybrid. Using Lys as an example, there was a large difference between the 2 samples; the high protein mutant DDGS contained 1.60% Lys vs 1.05% for the control DDGS. Standardized digestibility of amino acids was generally not different for the mutant DDGS and the control DDGS. Similar results were observed for Lys, Arg, and Trp for the DDGS produced from the second mutant corn hybrid. The Still Pro sample was analyzed to contain 53% protein (DM basis) with 2.22% Lys, 1.05% Met, 0.90% Cys, 2.06% Thr, and 3.08% Val. The standardized digestibility values for these amino acids were 84, 92, 87, 86, and 87%, respectively. The TMEn of the Still Pro sample was determined to be 3,372 kcal/kg DM. In conclusion, the results of this study indicate that the nutritional value of the 3 types of novel ethanol coproducts is equal to or superior to the nutritional values generally reported for conventional DDGS., (© 2019 Poultry Science Association Inc.)

1. The objective of this study was to investigate the variations in amino acid (AA) digestibility of lupin and pea grains in caecectomised laying hens. The relationship between AA digestibility and chemical constituents of the grains was determined. 2. Twelve variants of lupins and peas were each added to a basal diet at a concentration of 300 g/kg, at the expense of maize starch. The lupin and pea variants were separately investigated in two subsequent trials. Each trial consisted of two 7 × 7 Latin squares, each comprising the basal diet and six diets with lupins or peas. 3. Fourteen caecectomised laying hens (LSL-classic) were individually housed in metabolism cages and 120 g/d of experimental diets were provided for eight days. During the last four days, excreta were collected quantitatively and feed intake was recorded. A regression approach was used to determine the AA digestibility of the lupin and pea variants. 4. Amino acid digestibility of the lupins and peas was high, although significant differences in AA digestibility among the lupins and peas were detected. The digestibility of lysine was in the range of 0.87-0.91 and 0.87-0.93 for lupins and peas, respectively. The digestibility of methionine in lupins and peas varied between 0.80-0.88 and 0.72-0.90. Variations in AA digestibility in peas were more pronounced than in lupins. 5. Significant correlations between chemical constituents of lupins, such as alkaloids, and AA digestibility were detected in some cases, without a consistent pattern. In peas, tannin concentration and the insoluble protein fraction were negatively correlated with digestibility of some AAs, but only when one colour flower variant was considered. Trypsin inhibitor activity in peas was negatively correlated with AA digestibility, particularly for the white flower variants.

It is now well accepted that exposure to adverse environmental conditions in utero can predispose a fetus to disease later in life. Using an avian model to study the programming of disease has a unique advantage as it allows isolation of the direct effects of adverse conditions on fetal physiology, without any confounding effects via the mother or placenta. However, experiments in avian models are limited by the lack of well-established surgical protocols for the adult bird, which we have established in this study. Surgery was performed on seven young adult Bovan Brown chickens (body weight 1617±214 g, mean±s.d.) in order to instrument them with femoral arterial and venous catheters and a femoral arterial flow probe. Isoflurane and lidocaine were both found to have depressive effects on chicken cardiovascular function. Optimised methods of anaesthesia, intraoperative monitoring, surgical approach, postoperative care, and experimentation are described. Chickens recovered rapidly from surgery without significant blood gas perturbation, and basal in vivo cardiovascular studies were performed following 5 days of recovery. These techniques allow detailed investigation of avian cardiometabolic function, permitting determination of the consequences in later life of direct environmental insults to fetal physiology, isolated from additional effects on maternal physiology and/or placental endocrinology.

Assisted reproduction techniques in birds have been developed for zootechnical purposes and have been adapted for use in conservation of wild bird species. To develop a technique for obtaining follicles in live hens, 5 Rhode Island red hens ( Gallus gallus domesticus) were anesthetized, and abdominal ultrasound was performed to confirm the presence of ovarian follicles. A left celiotomy then was performed to obtain follicles in different stages of maturation for in vitro fertilization. The follicles were located by digital exploration, then extracted by isolating each follicle with the index finger of each hand, holding it by the stigma, and then applying slight traction towards the exterior of the coelomic cavity until the follicle separated from the ovary. In total, 18 of 30 (60%) follicles obtained were suitable for in vitro fertilization, but only 3 (16%) were fertilized successfully. All birds recovered from the procedure and remained in good condition postoperatively. Perfecting assisted reproduction technique holds potential benefits for determining sex of embryos by blastomeres sexing, supporting the conservation efforts of avian species, and benefiting research areas, such as genetic and biopharmaceutical research.

A survey of beak morphological abnormalities was performed on 6,201 chickens (egg-laying hens and chickens for meat production belonging to 25 flocks) brought to a poultry processing plant. The observed abnormalities varied among flocks with occurrence rates ranging from 0.48 to 46.67%. The occurrence was high in flocks subjected to beak trimming and varied significantly according to chicken breed, with the highest rates of abnormalities in a certain chicken breed. The most widely observed abnormalities were: 1) uneven growth of the upper and lower mandibles, mostly with elongation of the lower mandible (accounting for 64.8% of all abnormalities); 2) misalignment of the upper and lower mandibles, causing lateral deviation or crossing (16.3%); 3) sharp or jagged deformities of the mandible tips (10.1%); 4) permanent open beak, a deformity in which the beak did not close completely even when closed (5.8%); and 5) formation of tubercular swellings at the tips of the upper or lower mandibles (3.1%). This is the first report on the occurrence of beak abnormalities in beak-trimmed poultry in Japan.

Background: Flexor tendon injuries are one of the most common hand injuries and remain clinically challenging for functional restoration. Canine and chicken have been the most commonly used animal models for flexor tendon-related research but possess several disadvantages. The purpose of this study was to explore a potential turkey model for flexor tendon research., Methods: The third digit from human cadaveric hands, canine forepaws, turkey foot, and chicken foot were used for this study. Six digits in each of four species were studied in detail, comparing anatomy of the flexor apparatus, joint range of motioņ tendon excursion, tendon cross-sectional area, work of flexion, gliding resistance at the level of the A2 pulley, modulus of elasticity, suture retention strength, and histology across species., Results: Anatomically, the third digit in the four species displayed structural similarities; however, the tendon cross-sectional area of the turkey and human were similar and larger than canine and chicken. Furthermore, the turkey digit resembles the human's finger with the lack of webbing between digits, similar vascularization, tendon excursion, work of flexion, gliding resistance, mechanical properties, and suture holding strength. More importantly, human and turkey tendons were most similar in histological appearance., Conclusions: Turkey flexor tendons have many properties that are comparable to human flexor tendons which would provide a clinically relevant, economical, nonhuman companion large animal model for flexor tendon research., (Copyright © 2017 Elsevier Inc. All rights reserved.)

It is estimated that each year over 19 million pullets in the United States have their combs partially trimmed at a young age to improve egg production and feed efficiency. A possible disadvantage of trimming is that the comb and wattles may be essential for thermoregulation during hot weather allowing for conductive cooling of the blood through vasodilation of superficial vessels in these integumentary tissues. The objective of this study was to investigate the effects of partial comb and wattle removal, performed at 21 d of age, on the ability of White Leghorns to thermoregulate before, during, and after an imposed heating episode that averaged 34.6°C for 50.5 h. An increase in mortality at 20 h and body temperature at 48 h post initiation of the heating episode demonstrated that hens with trimmed comb and wattles were not able to cope with heat stress as effectively as controls. The increase in wattle temperature in controls as compared to trimmed hens during the heating episode and following heat stress provides supportive evidence that blood pools to the peripheral surface for conductive heat loss. During high temperatures typical of summer, trimmed hens attempted to compensate for their lack of ability to transfer heat from their comb and wattles to the environment through increased proportion of panting and wing spreading. Under less extreme conditions with lowered ambient temperatures, the trimming of the comb and wattles did not impair the ability of hens to thermoregulate, as body temperatures and behavior were similar to controls with no mortality. Egg weight was the only production parameter adversely affected by the trimming of the comb and wattles as compared to controls. The implication is that hens need their combs and wattles to thermoregulate effectively during periods of high environmental temperature. Pullets should not be subjected to a comb and wattle trim if they are housed in laying facilities that are not appropriately cooled during the summer., (© 2016 Poultry Science Association Inc.)

This study evaluated the effect of partial uropygialectomy (PU) on carcass traits of male and female Akar Putra chickens. Sixty chicks of each sex were evenly distributed into 5 treatment groups with 3 replicates per group containing 4 males and 4 females each, and reared for 12 wk. Homogeneity of the groups was satisfied with regard to the parity. Experimental treatments consisted of a control treatment (T1), and partial ablation of the uropygial gland was applied on the second, third, fourth, and fifth treatments at 3, 4, 5, and 6 wk of age, respectively. The chickens were fed ad libitum the same diets (1 to 13 d: starter; 14 d to slaughter: finisher). On the last d of the experiment, 12 birds were randomly selected from each treatment group (2 males and 2 females per replicate) and slaughtered to determine carcass characteristics, which included carcass weight, dressing percentage with or without eating giblets, and the relative weights of heart, liver, gizzard, thighs, wings, breast, back, and neck. From the results of the study, it was shown that the partial ablation of the uropygial gland at all ages had certain dependent effects concerning some carcass parameters, as shown by higher breast and back relative weights in males and breast relative weight in females. As a consequence, a positive effect also was noticed regarding the carcass morphology in terms of the increase in dressing percentage with or without eating giblets thus leading to an increase in the body weight and carcass weight. Furthermore, the best result was obtained in the second treatment when PU was applied at 3 wk of age compared with other experimental groups. Moreover, the current study provides a novel and economic alternative to enhance the body performance of poultry in general and Akar Putra chicken particularly., (© 2016 Poultry Science Association Inc.)

The learning of microsurgical techniques and the maintenance of microsurgical skills have been traditionally based on the use of living animals, mainly laboratory rats. This method although extremely valuable can be economically demanding both for the surgeon and the sponsoring institution; it also requires special training facilities that may not always be available or accessible. Furthermore ethical concerns can limit the use of living animals for training purposes. Alternative training methods, such as inert tubes and gloves have not gained popularity among surgeons since they do not offer an experience similar to that of a clinical situation. Non-living animal models include the use of chicken thighs and wings; they offer a practice experience that resembles a clinical situation to a considerable extent. This type of training is relatively cheap and easily available. The microscope and instruments required can be acquired over the internet, and the chicken pieces can be bought at the local supermarket. This approach allows a motivated trainee to rehearse different types of surgical techniques several times at a reasonable expense, helping to develop or maintain his surgical expertise if more complex facilities are not available. On the current manuscript we describe how to setup a small practice station, how to dissect the specimens, and how to practice both with the chicken thighs and with the chicken wings in a progressive fashion. This approach takes advantage on the versatility of the chicken thigh model and the small size of the chicken wing Brachial artery.

The wattles and comb of chickens are important for thermoregulation allowing for heat exchange during high temperatures. These integumentary tissues are sometimes trimmed to prevent tears if caught on cage equipment and to also improve feed efficiency; however, the procedure itself could be painful to chicks. Our objective was to determine the effect of trimming the comb and wattles on behavior, BW, feed usage, and the surface temperature of pullets. The wattles and comb of Leghorns were partially trimmed at 21 d age (n = 6 cages, 13 chicks each) with another 6 cages serving as controls. Behaviors were recorded 3 times daily for 1 h starting at 0800, 1200, and 1500 using instantaneous scan sampling observations conducted every 5 min prior to, on the d of, and after the trim. Group BW at 21, 28, and 36 d age and the amount of feed used for 7 d beginning at 21 and 29 d age were measured per cage. At 1300 h on d before and after the trim, thermal images of the pullet's beak, comb, eye, wattle, and shank were randomly taken on 3 pullets/cage. Smaller proportions of trimmed chicks were eating and greater proportions were sitting on the d of the trim as compared to the controls with the opposite trend occurring on 4 d post-trim (treatment by age interaction, P = 0.03 and 0.0001, respectively). Standing behavior differed only on the d of the trim where smaller proportions of trimmed pullets stood as compared to intact controls (treatment by age interaction, P = 0.0002). Trimming the comb and wattles did not affect preening, running, BW, feed utilization, and the surface temperature of the pullet. The indices of behavior suggest that on the d of the trim, pullets may have experienced temporary distress, but they returned to normal behavior by 5 h post-trim with no long-term effect on BW, feed usage, or surface body temperature., (© 2015 Poultry Science Association Inc.)

Polymelia was rarely recorded in birds; therefore, this report records the clinical and radiographic findings in a case of polymelia in a 7-mo-old layer Fayoumi chicken and the outcome of its amputation. The hen had two pericloacal extra limbs located caudal to the normal ones in an inverted position. The extra limbs were immovable and loosely attached to the underlying tissues. The supernumerary limbs had normal skin with ill-developed feathers. The extra limbs were fused proximally and crossed distally. Plain radiographic examination showed unequal numbers of bones and digits in both extra limbs. The right extra limb had a femur and tarsometatarsus while the left extra one had femur, tibiotarsus, and tarsometatarsus bones. The extra limbs appeared smaller than the normal ones and had neither muscles nor tendons. Amputation of the extra limbs under local infiltration analgesia was easy, safe, and curative.

Purpose: With the increasing use of microsurgical techniques in clinical work, regular laboratory training in these techniques has become essential. Several specialized materials have been used for this purpose. We investigated whether effective training could be provided with greater convenience and less expense using fresh chicken thighs. Also, we present the histologic characteristics of chicken femoral neurovascular structures., Methods: The femoral neurovascular bundles of fresh chicken thighs were dissected. Microanastomosis of vessels and nerves were performed with the aid of a microscope. Tissue from the midthigh of 8 chickens was examined histologically., Results: It was found to reduce the time taken to perform anastomoses using the chicken thigh model with statistically significance. The mean diameters (± standard deviations) of the arteries, veins, and nerves were 2.04 ± 0.17 mm, 1.45 ± 0.06 mm, and 1.24 ± 0.08 mm, respectively. The observed tunica adventitia to media ratio was 1:1 and multiple nerve fascicles were wrapped in a single epineurium. Microsurgery training with this material provides several advantages: ready availability, minimal expense, no scheduling or location limitations, neurorrhaphy training, no need for special facilities for animal care or anesthesia, and no need for the trimming of adventitia., Conclusion: The femoral neurovascular bundles of chicken are an appropriate and effective model for teaching and practicing microsurgery.

Objective: With the coming of the laparoscopy, multiple surgical techniques have been developed that have revolutionized the urological practice. The laparoscopic pyeloplasty has been one of the techniques most developed. However, there are very few training models that permit the surgeon to decrease the learning curve. An animal model of training for the laparoscopic pyeloplasty technique is described., Methods: Eight procedures of laparoscopic pyeloplasty were performed using the animal model (Gallus gallus) in the laparoscopic practice laboratory of the Urology Service of the University Hospital of Caracas. The preparation times of the model and the operation times of each surgeon were compared. The statistical analysis was made calculating the mean operation time, standard deviation, frequencies and percentages. A significant value was considered as p < 0.05., Results: The laparoscopic pyeloplasty procedure was performed successfully in all of the cases by two surgeons. The preparation time ranged from a maximum of 14 minutes to a minimum of 6 minutes, this being the same for both surgeons in the fourth case. The operation time ranged from a maximum of 65 minutes to a minimum of 43 minutes, observing significant differences when comparing the times individually for each surgeon. Only one case had filtration when comparing the patency of the specimen., Conclusions: The animal model of training of laparoscopic pyeloplasty that is described is economical, reproducible, of easy availability and it makes it possible to develop laparoscopic surgical skills and competency necessary for reconstructive surgery and techniques that warrant intracorporeal suture., (Copyright © 2011 AEU. Published by Elsevier Espana. All rights reserved.)

Routine removal of the tip of the beak of chickens within the poultry industry leads to changes in pecking behavior, which have previously been interpreted as being indicative of pain. By analyzing the force of pecks, with and without the topical application of an analgesic to the beak, we investigated if changes in pecking behavior were due to a loss of sensitivity in the beak or were pain related. Pecking behavior was compared between intact-beak and beak-trimmed chicks with or without topical application of lignocaine during a pain-free period (within 24 h of beak trimming) or after this period (d 2 to 9 of age). After pecking behavior tests, chicks were trained to use a magnetic stimulus to locate hidden food in 1 corner of a square arena. In unrewarded magnetic tests, the location of the chick relative to the magnetic stimulus was determined by automatic image recognition. Beak-trimmed chicks pecked harder than intact-beak chicks within 24 h of beak trimming (P = 0.04), possibly as a means of compensating for the loss of sensory feedback in beak-trimmed chicks. At 2 to 9 d of age, beak-trimmed chicks took longer to peck the pecking stimulus (P < 0.001) and showed fewer pecks in total (P < 0.001), suggesting a reduced pecking motivation. The force of pecks, however, did not differ among treatments at 2 to 9 d of age, suggesting that beak-trimmed chicks were not experiencing pain from the beak. In the magnetic tests, hungry intact-beak chicks stayed nearer to the magnetic stimulus (P = 0.005) and spent proportionally more time within 125 mm of the magnetic stimulus (P = 0.02) that had previously been associated with food than beak-trimmed chicks, which indicated that intact-beak birds were better able to detect the magnetic stimulus than beak-trimmed birds. We concluded that minor beak trimming at a young age did not result in pain in young domestic chicks, but instead led to impaired function of the magnetoreceptors and mechanoreceptors of the beak.

A 2-trial experiment was conducted to evaluate the effects of caponization on growth performance, carcass composition, and meat quality of medium growing broilers. Male chicks were caponized at 3 wk of age and reared until either 18 (trial 1) or 24 (trial 2) wk of age. In trial 1, the experimental groups included intact males, sham-operated chickens, and capons, whereas trial 2 comprised only intact males and capons. The concentration of testosterone was drastically reduced by caponization but remained detectable (trial 1). In both trials, BW was lower for capons during 4 to 9 or 10 wk of age when contrasted to intact males (P < 0.05). In trial 1, capons had heavier livers than intact males and sham-operated chickens. In addition, they had lighter hearts than sham-operated chicks (P < 0.05). In trial 2, capons displayed smaller drumstick and heart weights (P < 0.05). There was a tendency for increased fat pad weight in capons (P < 0.10). Caponization resulted in increased skin-fat weights of the thigh and the breast of 24 wk of age. This was also valid for carcass fat, when expressed as a percentage of the cold carcass weight, and intramuscular fat. Caponization had no effect on pH 24 h postmortem and cooking loss. Capons' breasts had lower shear values and displayed lighter, more yellow, and less red meat than that of intact males. Conclusively, caponization, without affecting growth performance, altered meat quality characteristics, resulting in special quality chicken meat.

1. The effects of a surgical operation, to implant a guide cannula in the chick hypothalamus for microdialysis, on behavioural responses and neural activity in broiler chicks are described. 2. General behavioural activities (feeding, preening, sitting, drinking, cage pecking and beak wiping), open field and locomotor activity tests were conducted to evaluate the effects related to surgery in the immediate 4 d following this procedure. Perfusion of Ringer solution with high K(+) after 4 d of guide cannula implantation was used to estimate the neural activity resulting from surgery through stimulation of monoamine release by in vivo brain dialysis. 3. The results of direct behavioral observations indicated that the stress provoked by surgical guide cannula insertion caused behavioural alterations that are particularly evident in the immediate days following this procedure. Open-field tests on day 4 after surgery showed that, compared to the intact control chickens, the treated chicks had a shorter latency to ambulate and defecate, with more vocalisation. Locomotor activity was less in the treated chicks than in the controls. 4. After 4 d of guide cannula implantation, the serotonin concentration started to increase 30 min after the onset of perfusing high-K(+) Ringer solution. It reached its highest value at one hour, suggesting that the 4 d after surgery is enough to alleviate some neurochemical dysfunction resulting from surgery. The results of behavioural observations, open-field and locomotor activity tests indicate that the surgical operation caused stress and fear in chicks which persisted up to 4 d.

This research examined the effects of infrared beak treatment on layer chicks. Seventy-two layer chicks were assigned to hot-blade trimming (HB), infrared treatment (IR), or a control treatment. Day-old chicks were pair-housed by treatment. Beak photographs, behavior, and production indices were obtained at intervals for 9 wk posttreatment. All beaks were normally shaped at the onset of the study, and no perceptible treatment-related differences in shape occurred over time (P > 0.05). Posttreatment, HB birds had shorter beaks relative to the other 2 groups (P < 0.05). Control and IR beaks remained comparable in length until tissue eroded in IR beaks at 1 to 2 wk posttreatment. Thereafter, beak length increased in all treatments over time (P < 0.01). Two weeks posttreatment, beaks were longest in control birds, intermediate in HB birds (P < 0.001), and shortest in IR birds (P < 0.001). The HB birds had abnormal deviations from a normal upper-to-lower mandible length ratio than the IR or control birds (P < 0.05). Notable effects of treatment on production emerged by +2 d and persisted for 5 wk. Growth and feed intake were lower in HB and IR birds compared with control birds (P < 0.05), with IR birds performing least well until the fourth week of the study (P < 0.05). Thereafter, they performed similarly to the HB group. Feed waste was lowest in the IR group and was generally greatest in the control group (P < 0.05). There was an overall effect of trimming, irrespective of method, on behavior, particularly eating and drinking behaviors (P < 0.05). Specifically, IR birds were less active (P < 0.01) and spent less time eating (P < 0.01) and drinking (P < 0.05) than did control birds. Behavior in HB birds often ranked intermediate in duration and incidence, but was not significantly different compared with behavior measured in the control and IR groups. Effects of treatment on behavior were not present after 1 wk posttrimming. Results indicate that acute pain occurred with both trimming methods. Although the impact of trimming appeared to be greatest in the IR birds initially, these differences disappeared relatively quickly, and subsequent performance was similar in both trimmed groups.

Prebiotics, such as indigestible oligosaccharides, are considered to be possible dietary alternatives to antibiotic growth promoters in poultry. The effects of indigestible oligosaccharides on nutrient digestibility in poultry are largely unknown. Therefore, an experiment was conducted to evaluate the effects of several oligosaccharides on amino acid digestibility and TMEn in roosters. The dietary treatments consisted of a corn-isolated soy protein control diet or that diet supplemented with 4 or 8 g/kg of inulin, oligofructose, mannanoligosaccharide (MOS), short-chain fructooligosaccharide, or transgalactooligosaccharide (TOS). Each of the 11 diets was tube-fed (30 g) to 4 cecectomized and 4 intact Single Comb White Leghorn roosters that had been fasted for 24 h. Excreta were then collected for the following 48 h, freeze-dried, and analyzed for amino acid content. The true digestibility of lysine and valine was increased (P<0.05) in cecectomized roosters fed 8 g/kg of MOS or TOS when compared with roosters fed the control diet. In addition, methionine digestibility was improved (P<0.05) in cecectomized roosters fed 4 g/kg of MOS or short-chain fructooligosaccharide and by 8 g/kg of oligofructose or TOS. The true digestibility of isoleucine was increased (P<0.05) in cecectomized roosters fed 8 g/kg of MOS or 4 or 8 g/kg of TOS. The magnitude of the increases in amino acid digestibility coefficients for cecectomized roosters ranged from 3 to 9 percentage units. Feeding either 4 or 8 g/kg of inulin to intact roosters decreased (P<0.05) the true digestibility of methionine. The oligosaccharides generally had no significant effect on TMEn. The results of this study indicated that the indigestible oligosaccharides had no significant effect on the digestibility of most amino acids in a corn-isolated soy protein diet. The digestibility of a few amino acids, however, was increased by some oligosaccharides in cecectomized roosters but not in intact roosters.

Detailed behavioural observations were made of broiler breeder chicks after their beaks had been trimmed by an automated infrared treatment at one day of age or by the traditional hot-blade method at one day or seven days, or after they had been sham-trimmed or left untreated. Observations took place immediately after the treatments and at regular intervals until six weeks of age; beak length and bodyweight were also measured regularly. There were no significant effects on the behaviour of the chicks in the first hour after trimming or in the subsequent six weeks. Variability in beak length was low within the treatments and there was significant regrowth, but it was least in the birds that had been hot-blade trimmed at seven days. Both beak-trimming methods were associated with small but significant reductions in bodyweight, with the hot-blade-treated birds being more affected.

Five sources of corn distillers dried grains with solubles (DDGS), which varied in darkness of color, were collected from several processing plants in the Midwestern United States. Sources of DDGS were analyzed for their amino acid and energy contents, measured for color score, and evaluated for TMEn, apparent amino acid digestibility, and true amino acid digestibility. A precision-fed rooster assay was used, in which each DDGS sample was tube fed (25 g) to adult cecectomized roosters, and the excreta were collected for 48 h. The experiment was conducted as a randomized complete block design with 8 replicates. Seven adult roosters (averaging 75 wk of age) were used in each period, with 5 fed the DDGS sources and 2 fasted to estimate basal endogenous amino acid losses. One source (no. 5) was the darkest, 2 sources (no. 2 and 4) were light, whereas 2 other sources (no. 1 and 3) were intermediate in color as measured by a colorimeter. Total lysine content of the DDGS sources ranged from 0.48 to 0.76%, with the lowest lysine content in the darkest DDGS source. Apparent and true lysine digestibility was approximately 30 and 15 percentage units lower (P < 0.05), respectively, in the dark-colored source (no. 5) than in the other 4 sources. Average apparent and true digestibility of the essential amino acids were 10 and 8 percentage units lower (P < 0.05), respectively, in source 5 than the other 4 sources. The TMEn content of the 5 DDGS sources was also lower (P < 0.05) in the darkest DDGS (no. 5). Our results suggest that when the color score of a DDGS source, as measured by a colorimeter, reached a certain threshold (lightness between 28 and 34), amino acid availability and true metabolizable energy content may be reduced. This reduction was particularly evident for lysine, which had the lowest digestibility in the darkest DDGS source. These results suggest that dark-colored DDGS may have been overheated during drying, causing Maillard reactions to be more extensive and resulting in a lowered total lysine content, lysine digestibility, and TMEn content.

Purpose: To develop an experimental animal model of laser in situ keratomileusis (LASIK) in hens., Methods: One hundred adult hens underwent a 60-microm corneal flap followed by -4 diopter excimer laser ablation. Surgical technique, clinical course, and pathology correlations are presented., Results: Sixty percent of animals had a successful LASIK outcome according to clinical observations. Pathology showed the integrity of Bowman's layer and homogeneous flap in all eyes with good clinical outcomes. Flap complications such as buttonholes (5%), free-flaps (2%), and slipped flaps (3.4%) occurred with the surgical technique. Corneal abscess (2.9%) was also present. Loss of transparency was noted in 26.4%, which correlates with epithelial ingrowth detected by light histology study., Conclusions: An experimental animal model of LASIK was successfully developed in adult hens. This model could be useful in the study of wound healing and pharmacological modulation after LASIK in an animal with Bowman's layer.

A model of limb deviation induced by hemi-circumferential periosteal stripping of the distal tibiotarsus of domestic chicks is described. This model has been developed to study the effects of periosteal stripping on the cellular, mechanical, vascular, and biochemical status of the immature bone and growth plate. It is hoped that such studies may further elucidate the mechanisms involved in altered bone growth following periosteal stripping techniques which are used in human and equine orthopaedics for the management of leg length discrepancies and angular limb deformities respectively (Auer and Martens 1980, Warrell and Baker 1987). Hemi-circumferential periosteal stripping of the left distal tibiotarsus of 28-day-old chicks resulted in significant change in metaphyseal-diaphyseal angle with time, compared to both the controls and the untreated right legs (P<0.0001). This model of limb deviation developed rapidly and consistently, and the procedures were well tolerated by the birds over the short survival time (maximum 28 days).

Study Design: Stages of the surgical procedure for pinealectomy in chickens were identified. Groups of chickens were selected for each stage. Scoliosis development was identified from radiographs., Objectives: To determine the critical stage of surgery for pinealectomy after which scoliosis develops in young chickens., Summary of Background Data: Pinealectomy in young chickens consistently produces scoliosis in young chickens that has many characteristics similar to those seen in patients with adolescent idiopathic scoliosis. The mechanism behind this phenomenon remains unknown., Methods: Five distinct stages in the pinealectomy surgery were identified. Groups of chickens were selected to undergo surgery to represent these five stages. Scoliosis was determined from weekly radiographs., Results: Cutting the pineal stalk was identified as the critical stage in the surgery after which scoliosis developed. The incidence of scoliosis did not increase after more extensive surgery in which the pineal bulb was removed from the skull. This stage was also correlated with a significant reduction of serum melatonin levels., Conclusions: Cutting the pineal stalk was identified as the critical stage of pinealectomy surgery after which scoliosis may develop. This stage was also correlated with the significant reduction of average serum melatonin levels. These results allow the focus of attention into the mechanism behind this phenomenon to center on the consequences of cutting the pineal stalk rather than total removal of the pineal gland.

Survival surgeries upon chicks are commonly used in auditory research. Appropriate anesthesia is usually obtained with intramuscular or intraperitoneal injections of systemic agents. These techniques have several drawbacks, including delayed onset of anesthesia, difficulty in adjusting the dosage to accomodate individual animals' different responses, prolonged recovery times, and in some cases substantial mortality. We present a technique of administering inhaled isoflurane via an endotracheal tube which we have used for over a year with excellent results. With this agent, onset of deep anesthesia is very rapid, dosage can be titrated readily, overdosage is survivable, complete recovery occurs within a few minutes and mortality is rare. This technique may be valuable for other auditory scientists performing survival surgery in avian species.

Our previous studies have shown that an environment of constant light (CL) can lead to development of high degree of hyperopia in newborn chicks by inducing severe corneal flattening, and compensatory growth of the vitreous chamber. We wish to know whether the abnormal eye growth and progressive hyperopia under CL conditions is accomplished by a mechanism that uses the visual processing pathways of the central nervous system (CNS) or by a mechanism located in the eye. Thirty white leghorn chicks (Cornell K-strain) were raised under 12 h light/12 h dark (12L/12D) for either optic nerve section (ONS) or ciliary ganglion section (CGS). Another 30 chicks were raised under CL for ONS or CGS. Refractive states and corneal curvatures were measured by infrared (IR) photoretinoscopy and IR keratometry, respectively. The axial lengths of the ocular components were measured by A-scan ultrasonography. Both ONS and CGS surgery produced dilated pupils and accommodative paralysis. Four weeks after surgery, CGS eyes exhibited a hyperopic defocus, flatter cornea, and shorter vitreous chamber depth under both CL and normal conditions, whereas ONS eyes showed a smaller radius of corneal curvature and shallow vitreous chamber only in the normal light cycle group. CGS eyes of CL chicks showed significantly deeper vitreous chambers than did fellow control eyes. Our results indicate that optic nerve section does not seem to influence CL effects. Thus, local mechanisms may play a major role in the ocular development of chicks. The ciliary nerve is necessary for the normal corneal and anterior chamber growth, and prevents CL effects. The progressively increasing vitreous chamber depth under CL may be influenced by both local and central mechanisms.

Objective: To determine the minimum anesthetic concentration for sevoflurane and effects of various multiples of minimum anesthetic concentration on arterial pressure and heart rate during controlled ventilation in chickens., Study Design: Prospective experimental study., Animals: Seven healthy chickens, 6 to 8 months old, weighing 1.6 to 3.4 kg., Methods: A rebreathing, semiclosed anesthetic circuit was used. Anesthesia was induced by mask with sevoflurane in oxygen. Each chicken was endotracheally intubated, then controlled ventilation was started and the end-tidal CO2 partial pressure was maintained at 30 to 40 mm Hg. Body temperature was maintained at 39.5 degrees to 41.0 degrees C. The inspired and end-tidal sevoflurane concentration were monitored with a multigas monitor. Minimum anesthetic concentration was determined as the minimal end-tidal sevoflurane concentration which prevented gross purposeful movement in response to clamping a toe for 1 minute. After the determination, the cardiovascular effects of sevoflurane at 1.0, 1.5, and 2.0 times the minimum anesthetic concentration were determined., Results: The minimum anesthetic concentration for sevoflurane was 2.21% + 0.32% (mean +/- SD). Mean arterial pressure and heart rate at minimum anesthetic concentration were 84 +/- 13 mm Hg and 150 +/- 58 beats/min, respectively. There was a dose-dependent decrease in arterial pressure. The heart rate did not change significantly over the range 1 to 2 x minimum anesthetic concentration. No cardiac arrhythmias developed throughout the experiments., Conclusions and Clinical Relevance: The minimum anesthetic concentration for sevoflurane in chickens was within the range of minimum alveolar concentration reported in mammals. When the concentration of sevoflurane is increased during controlled ventilation in chickens, decrease in arterial pressure should be expected.

Objective: To determine the effects of epidermal growth factor (EGF) or insulin-like growth factor (IGF) on tenoblast migration on absorbable suture material using an in vitro model., Study Design: An in vitro evaluation of tenoblast migration., Animal or Sample Population: Segments of the long digital flexor tendon were obtained from Cobb chickens (9-11 weeks old) immediately after the birds were euthanatized., Methods: Tissue culture explants of tendons containing absorbable suture material were treated with either EGF or IGF. Tenoblast migration was assessed daily using an inverted microscope equipped with bright field and phase optics. Tenoblast migration was assessed according to the following criteria: time of first cell appearance, percent of explant interfaces producing cells, migration distance, and terminal migration index at 120 and 168 hours., Results: EGF had a stimulatory effect on tenoblast migration for cells originating from the endotenon interfaces. No significant effect was noted on migration distance for cells originating from epitenon interfaces. A stimulatory effect on the percentage of interfaces producing cells and a significant decrease in time of first cell appearance were also observed after EGF treatment. IGF-stimulated cell migration distance for epitenon interfaces but this stimulatory effect did not occur at a higher concentration. IGF was inhibitory to percent of epitenon and endotenon interfaces producing cells but decreased time of first cell appearance at low concentration., Conclusions: Using an in vitro model, EGF had a stimulatory effect on tenoblast migration. IGF was stimulatory at low concentration levels but inhibitory at a higher concentration. Increased migration distance was observed for endotenon interfaces after EGF treatment and for epitenon interfaces after IGF treatment., Clinical Relevance: EGF or IGF might enhance tendon repair if they could be delivered to the repair site. Incorporation of EGF or IGF into suture material would allow slow release and prolonged exposure of migrating tenoblasts to growth factors.

The objectives of these studies were to predict the effects of roasting and extrusion temperatures of whole soybeans (SB) on intestinal protein digestibility in cattle. Intestinal digestibility was assessed with a two-stage in vitro or in situ ruminal incubation/precision-fed cecectomized rooster bioassay. In Exp. 1, whole SB (raw SB or SB roasted to 141, 149, or 157 degrees C exit temperature from a commercial roaster and steeped for 30 min) were incubated in strained ruminal fluid and McDougall's buffer (50:50) at 39 degrees C for 16 h. In Exp. 2, SB (ground raw SB or SB extruded at 116, 138, or 160 degrees C) were placed in polyester bags (20 x 30 cm) and suspended in the ventral rumen of steers for 16 h. Lyophilized residue of the in vitro or in situ incubations and samples of raw SB and most extensively heated SB (roasted SB at 157 degrees C or extruded SB at 160 degrees C) for each respective experiment were crop-intubated to cecectomized roosters. Total excreta were collected for 48 h after intubation and lyophilized, and amino acid (AA) concentrations were determined. In Exp. 1, total AA digestibility was 61.6 and 84.5% for unincubated whole raw SB and 157 degrees C roasted SB, respectively, and 66.2, 88.9, 91.3, and 91.6% for in vitro residues of whole raw SB and SB roasted at 141, 149, and 157 degrees C, respectively. Trypsin inhibitor (TI) activity was 20.09, 1.69, 1.54, and 1.84 mg/g fat-free DM for unincubated whole raw SB and 141, 149, and 157 degrees C roasted SB, respectively, and 30.84, 1.01, .90, and .26 mg/g fat-free DM for in vitro residues of whole raw SB, 141, 149, and 157 degrees C roasted SB, respectively. In Exp. 2, total AA digestibility was 68.5 and 87.7% for unincubated ground raw SB and 160 degrees C extruded SB, respectively, and 81.9, 91.3, 89.7, and 89.4% for in situ residues of ground raw SB and 116, 138, and 160 degrees C extruded SB, respectively. Trypsin inhibitor activity was 17.61, 4.89, 4.08, and 1.56 mg/g fat-free DM for unincubated ground raw SB, 116, 138, and 160 degrees C extruded SB, respectively, and 3.62, .59, .55, and .21 mg/g fat-free DM for incubated ground raw SB, 116, 138, and 160 degrees C extruded SB, respectively. Heat treatment by roasting and extrusion improved AA digestibilities of SB, but there were no differences detected among the roasting or extrusion temperatures. Ruminal fermentation did not eliminate the negative effects of TI activity on intestinal digestibility of AA in whole SB but did reduce TI activity in ground SB.

Objective: To determine the effects of the amount of break removed and cauterisation time on neuroma formation in hens., Design: A pathology study with controls., Animals: Twenty domestic fowl were beak-trimmed. Three non-beak-trimmed domestic fowl were used as controls., Procedure: Beaks of two age groups with two levels of beak removal and either 2 s or 4 s cauterisation, were investigated macroscopically and microscopically for deformities., Results: Scattered trauma-associated neuromas were present in the beaks of pullets 10 weeks after moderate trimming at hatch. Neuromas were not present in beaks of adult hens that had been similarly trimmed. Sensory corpuscles were present 10 and 70 weeks after moderate trimming, though fewer in number than in intact control hens. In contrast, trauma-associated neuromas persisted in beaks of 70-week-old hens that had been severely trimmed at hatch. A range of deformities that were absent in moderately trimmed hens, were observed in hens with severely trimmed beaks. Receptors were not seen in severely trimmed beaks., Conclusion: Beak-trimming at hatch induces the formation of neuromas, regardless of the amount of tissue removed. There is a critical amount of beak tissue that can be removed, beyond which trauma-associated neuromas will not resolve, but will persist in mature hens.

Two experimental diets consisting of a basal diet either undiluted or diluted with 1% pectin-based gelling agent were given to intact or cecectomized adult cockerels for a balance experiment. The digestibilities of the water-soluble added pectin were 83.2 and 61.4% in intact and cecectomized birds (P < .05), respectively. Lactic acid excretion varied from 407 to 2,692 mg/kg, acetic acid from 790 to 1,214 mg/kg, propionic acid from 108 to 240 mg/kg, and butyric acid from 50 to 90 mg/kg dry matter intake. Organic acid excretions were the lowest for intact birds fed the basal diet and the highest for cecectomized birds fed the pectin diet. Addition of pectin induced an increase (P < .001) in organic acid excretion, especially for lactic acid in cecectomized birds. Organic acid excretion was greater (P < .001) in cecectomized than in intact cockerels. The increase in organic acid excretion induced by pectin addition amounted to 9 and 62% of the digested fraction of pectin in intact and cecectomized cockerels, respectively. The results showed the water-soluble nonstarch polysaccharides to be digested both in ceca and upper tract. It was also shown that the major part of organic acids produced from fermentation are absorbed in the ceca.

In each of two duplicate trials approximately 2,500 day-old Peterson x Arbor Acres straight-run broiler chicks were equally divided between two treatments of three pens each. Treatment 1 was maintained as controls (C), and Treatment 2 birds were precision beak-trimmed (PBT) at 7 days of age. Feed and water were supplied for ad libitum consumption to both groups. Trials 1 and 2 were initiated in March and June, respectively. Performance of spring-reared broilers were comparable regardless of beak trimming procedure, except that PBT broilers experienced slightly higher mortality after PBT. Final body weights of the summer-reared broilers were 15% lower than those reared in the spring. Additionally, PBT resulted in significantly reduced final body weights and feed intake. There were no significant differences in mortality or feed conversion due to PBT.

Three studies were conducted to evaluate N and amino acid (AA) availability from processed soybean (SB) products. In Exp. 1 and 2, treatments consisted of corn-cottonseed hull basal diets plus SB products including SB meal (SBM); ground, raw SB (RSB); or extruded SB (ESB). In Exp. 1, 15 Suffolk (28.6 kg) and 15 Louisiana native breed (16.3 kg) ewe lambs were used in a 35-d growth trial. Although breed affected (P < .10) DMI and ADG of lambs, the diets did not (P > .10). In Exp. 2, 12 Suffolk wether lambs (34.0 kg) were used in a 3 x 3 multiple-square Latin square design N metabolism trial. Lambs fed RSB tended (P = .13) to retain more N than those fed ESB, but N retained by lambs fed RSB and ESB was similar (P > .10) to that of lambs fed SBM. In Exp. 3, four crossbred steer calves (240 kg) were used in a 4 x 4 Latin square design N metabolism trial with the above treatments plus heat-damaged SB (HDSB). Calves fed RSB and ESB retained similar (P > .10) amounts of N. Compared with calves fed RSB and ESB, calves fed SBM retained more (P < .10) N. Calves fed HDSB retained less (P < .10) N than those fed other diets. The individual SB products and the total mixed diets used in Exp. 3 were incubated intraruminally in nylon bags and the residual DM recovered and precision-fed to cecectomized roosters to estimate its intestinal AA digestibility. Digestibility of residual AA seemed to be relatively uniform across AA.(ABSTRACT TRUNCATED AT 250 WORDS)

A surgical procedure for the separation of avian urinary and fecal excrement, in birds as young as 3.5 wk of age, was developed and used to quantify ambient temperature effects on urine production and composition. The colostomized broilers were used in two experiments to estimate urine production, osmolality, and contribution to water, nitrogen, and thermobalance of birds exposed to thermoneutral (24 C, TN) and heat-distressed (35 C, HD) environments. Urine production averaged over three 12-h periods was greater (P < .05), at 101 versus 51 mL/12 h per kilogram of BW and osmolality lower (P < .05) at 142 versus 220 mOsm/kg urine during HD and TN, respectively, in Experiment 1; and averaged over one 12-h period 82 versus 32 mL/12 h per kilogram of BW and 136 versus 208 mOsm/kg in Experiment 2 for HD and TN, respectively. In Experiment 1, urine production per milliliter of water consumed was increased (P < .05) by HD during Periods 2 and 3 even though in both experiments the values were similar during the first 12 h. Both urinary nitrogen and osmolar losses were increased (P < .05) by 50 and 89.2%, respectively, during HD, but without effect on fecal nitrogen. Evaporative cooling of broilers was increased (P < .05) by 154% during HD. These studies provide a well-defined colostomy procedure and suggest that broiler urine production and composition as well as overall thermobalance, water, and nitrogen balance are strongly impacted by acute HD.

Two experiments were conducted to compare beak treatment effects on pullets of three genetic stocks. Within each stock, equal numbers were assigned to three treatments: no beak trimming (IN), beak trimming once (1X), and beak trimming twice (2X). Beak treatment, genetic stock, and age effects along with interactions among main effects were examined for production-associated traits during rearing and brief periods of early egg production. Beaks of 1X and 2X pullets remained shorter than those of IN pullets through final measurements at 36 and 32 wk of age in Experiments 1 and 2, respectively. However, differences in beak length decreased as age increased. Upper beaks of 2X pullets remained shorter than those of 1X pullets, but lower beaks of 1X and 2X pullets did not differ by 20 wk in Experiment 2. Weight gains, feed usage, and efficiency of growth were affected by beak treatments. Beak trimming reduced gains, feed eaten, feed wasted, and total feed used, and 2X pullets used their feed more efficiently for weight gain and egg production. A general decrease occurred in differences among beak treatments for weight gains, feed eaten, feed wasted, and efficiency of gains with increasing age during rearing. Nevertheless, significant differences in feed consumed, feed wasted, and efficiency of feed used for egg production indicated an economic advantage in favor of beak trimming.

Pullets whose beaks were trimmed once (at 9 days) and twice (at 9 days and 9 wk) were able to ingest feed, in the form of mash, more rapidly under competitive feeding conditions and at least as rapidly in the absence of competition as pullets with intact beaks. Tests of feeding rate, when pullets fed in groups, were carried out after a feed deprivation period of 7 h at ages of 10 through 16 wk. Similar tests were done at 18 wk, when pullets fed without competition. Genetic stock and age had significant effects on frequency of agonistic acts at the feeder and displacements from the feeder during 5-min tests under competitive feeding conditions. Age influenced the number of pullets feeding simultaneously and amount of feed eaten per pullet during the same feeding tests. No interactions were detected among beak treatment, stock, and age for feeding-related behaviors or rate of feed consumption during competitive feeding. In noncompetitive feeding tests, genetic stock affected feeding rate but no stock by beak treatment interaction was present.

Digital flexor tenorrhaphies were performed in 32 8-week-old chickens with polyglyconate, polybutester, or nylon. There was no difference in maximum loads to failure at weeks 4 or 8. Polyglyconate and polybutester tenorrhaphies were significantly stronger at week 8 than all tenorrhaphies at week 4. Nylon tenorrhaphies at week 8 were not significantly stronger than any tenorrhaphy at week 4. The tenorrhaphies consistently had immature scars at week 4 and more mature scars at week 8. Scar maturity was not appreciably different between any of the suture materials at week 4 or week 8. There was no apparent difference in tissue reactivity to any of the suture materials at weeks 4 or 8.

Beak trimming pullets at an early age is a widespread industry practice. There is some concern that this practice may have effects on the subsequent performance of the birds in the production phase. Effects of beak treatment (trimmed or untrimmed) and rearing floor type (litter or wire) on performance of caged layers were evaluated in a 2 x 2 factorial arrangement of treatments. Pullets that were trimmed or untrimmed at 10 days of age and reared on either litter or wire floors were placed in a cage house. Production factors and stress measurements were recorded to determine detrimental effects of the early trimming and rearing floor types. No interactions (P = .15) between rearing floor type and beak treatment were observed for BW, feed consumption, egg production, heart weight, spleen weight, or blood corticosterone. However, an interaction (P = .02) between rearing floor type and beak treatment was observed for adrenal weight. There were no differences (P = .08) in the final BW of the pullets. Birds reared on litter ate considerably (P = .0002) more than those reared on wire. There were no differences (P = .27) in egg production rate. Adrenal weights were different (P = .007), with the litter-raised birds having much smaller adrenals at the end of the 36-wk trial. Hearts of the beak-trimmed birds were smaller (P = .02) than those of the untrimmed birds. There were no differences in spleen weights (P = .07) or blood corticosterone levels (P = .07). Differences in the feather cover were observed.

Pullets of stocks derived from the North Central Randombred White Leghorn population without selection (C) or selected (S) on family performance when kept with beaks intact in multiple-hen cages were compared. Pullets had intact, one-fourth, or one-half of the beak removed (IN, 1/4R, and 1/2R, respectively). No stock differences were detected for behavior traits or other measures during the rearing period. However, beak-trimmed pullets were more inactive and feeding behavior was depressed in 1/2R pullets 1 wk after beak trimming. At 16 wk, 1/4R pullets' beaks had regrown but 1/2R pullets' beaks continued to be shorter than IN pullets' beaks. No differences in fearfulness were found between genetic stocks or among beak length treatments early in the laying period. Deaths from beak-inflicted injuries accumulated steadily from 18 wk until the study was ended at 40 wk. Cannibalistic deaths occurred less frequently in S as compared with C pullets within each beak treatment. As the amount of beak removal increased, beak-inflicted mortality decreased. The S pullets had earlier sexual maturity, lighter egg weights, and greater hen-housed egg production and egg mass than C pullets, and 1/2R pullets had greater egg production than 1/4R and IN pullets. Genetic stock by age and beak treatment by age interactions were present for hen-housed production and egg mass, and the interactions appeared to result primarily from increased mortality from cannibalistic pecking with increased age.

The performance of three commercial strains of White Leghorn layers was compared following beak trimming (BT) at 6 or 12 wk of age when fed diets containing 4.45 and 6.30% fiber between 6 and 12 or 12 and 18 wk of age, respectively. Body weights were lower at 12 wk in the 6-wk BT pullets, but were heavier at 18 wk when compared with the 12 wk BT pullets. Eighteen-week body weights were unaffected by feeding regimens. Six week BT resulted in higher hen-day and hen housed egg production, total egg mass, feed consumption, and total egg income. Profitability was superior for the 6-wk BT treatment (P = .072). Feeding the high fiber diets from 6 to 12 or 12 to 18 wk of age resulted in no differences in any of the adult performance traits measured compared with the control diet.

White Leghorn line C chicks were surgically bursectomised (Bx) in ovo to eliminate antibody production. After inoculation with infectious bronchitis virus (IBV) at 14 days after hatching, Bx chicks experienced a more severe and longer lasting infection than intact chicks. The severity and duration of clinical infection in the Bx chicks resembled that previously observed in the highly susceptible line 15I chicks, however no increase in mortality was observed, in contrast to the high levels of mortality recorded in IBV-inoculated line 15I chicks. After secondary challenge the degree of damage to the ciliated epithelium of the trachea was greater in the Bx chicks than in the intact chicks. The results indicate that, although antibodies play an important role in recovery from IBV infection, other immunological factor(s) may also be involved.

The experimental material were female chicks of Tetra SL cross-breed. It was found out that in the spleens of 8-week old chicks, bursectomized in the neonatal period, there occurred not only a decrease in the number of type I and II germinal centres, but also weakening of the reaction to acid phosphatase as well in those organic structures as in periellipsoidal lymphatic tissue. Single administration of sheep red blood cells to the chicks exerted varied effects on the germinal centres in the spleen depending on whether the recipient chicks had or had not been bursectomized. In non-bursectomized chicks there was observed an increase in the number of both types centres as well as intensified in them reaction to acid phosphatase. Now, after administration of the antigen to bursectomized chicks only the number of type II germinal centres was found to have increased with intensified in them reaction to acid phosphatase, while the number of type I centres and intensity of reaction to acid phosphatase stayed almost unchanged, i.e. at the level lowered by bursectomy. On these grounds it may be thought that only type II reproductive centres retain their reactivity to administration of the antigen irrespective of whether the chicks had or had not been bursectomized. Now, the sensitivity of type I centres of the spleen seems to be influenced, first of all, by the biological function of bursa Fabricii. Reactivity similar to that manifested by type I germinal centres, i.e. intensified reaction to acid phosphatase and growth after administration of antigen, was found also in periellipsoidal lymphatic tissue, though, only in non--bursectomized chicks. In the aspect of this research the results obtained constitute the basis for further study of the mechanism of immunological response in chicks.

Astra S hybrid chickens, bursectomized within 48 hours of life, were administered the following antigens: virus of Newcastle disease (NDV) in the fourth week of life and sheep red blood cells (SRBC) or bovine serum albumin (BSA) 10-12 days later. Level of antibodies to the antigens was determined in the sixth week of the birds' life. Administration of SRBC to non-bursectomized chickens inoculated with NDV brought about, in comparison with the chickens not administered SRBC, several-time increase in the titre of anti-NDV antibodies, the anti-SRBC antibodies in chickens inoculated and not inoculated with NDV stayed at the same level. Now, administration of BSA to non-bursectomized chickens inoculated with NDV, in comparison with those not stimulated with BSA, brought about a slight decrease in the titre of anti-NDV antibodies. Bursectomized chickens appeared to exhibit much weaker reaction to the three antigens than the non-bursectomized ones. Administration of SRBC to bursectomized chickens inoculated with NDV exerted no influence on the level of anti-NDV antibodies but, in comparison with those not inoculated with NDV, the titre of anti-SRBC antibodies in them increased twice. Inoculation of bursectomized chickens with NDV followed by administration of BSA brought about, in comparison with those not administered BSA, an increase in the titre of anti-NDV antibodies. At the same time bursectomized chickens inoculated with NDV exhibited a lower level of anti-BSA agglutinins in comparison with the not inoculated ones.

A surgical method for selective denervation was developed to facilitate investigations about the postmortem characteristics of denervated pectoralis muscles in chickens, Musculus (M.) pectoralis. The M. pectoralis was denervated in anesthetized chickens unilaterally or bilaterally by excising a 1-cm section of the nervus pectoralis as it branched from the N. medianoulnaris in the brachial plexus. Denervation resulted in significant (P less than .01) and consistent depression in the relative weight of M. pectoralis from the wk 2 through 17 postoperative. The relative weight of the functionally antagonistic M. supracoracoideus was unaffected by ipsilateral denervation of the M. pectoralis. The M. coracobrachialis acts in synergism with the M. pectoralis and displayed significant muscle atrophy at 4, 6, 8 and 17 wk postoperative in treatment groups where the ipsilateral M. pectoralis was denervated. Only the M. pectoralis displayed histological signs of denervation in transverse cryostat sections. Denervated tissue was characterized by atrophic and rounded muscle-fiber profiles, an increase in the endomysial and perimysial connective-tissue spaces, and leucocytes within degenerative perimysial nerves from 2 through 17 wk postoperative. Signs of denervation were distributed throughout seven zones sampled from the M. pectoralis. This study indicated that selective denervation of the M. pectoralis was achieved and that postoperative histology was necessary to accurately assess denervation.

The effects of partial adenohypophysectomy on comb size, testicular weight, and histology 20 or 30 days after the operation are described and discussed in relating these observed changes with the volume of remaining adenohypophyseal tissue. From the present observation, it is concluded that 1) the response of the domestic fowl to partial deficiency of adenohypophyseal tissue may be more sensitive than that of some mammals, 2) the decrease in testicular weight and tubular diameter precedes the histological change in testis and comb regression, and 3) to maintain fully active testicular function, more than 75% of the adenohypophysis is needed. About 40% of the adenohypophyseal tissue including a remnant of cephalic lobe can stimulate spermatogenesis, but the spermatozoa produced were partially abnormal. The critical amount of adenohypophyseal tissue for normal spermiogenesis may exist between 55 and 75%. All histological change is initially observed in the center of testis and then extended toward the periphery. It is suggested that the cephalic lobe contains at least a trace of ICSH in addition to FSH.