Method for collecting semen from the ostrich (Struthio camelus) and some of its quantitative and qualitative characteristics.

1. Four methods of semen collecting that involved interruption of mating in two breeding ostrich pairs were tested: an artificial vagina was tested without promising results; the funnel method, in which a funnel was placed under the phallus of the tested male immediately after mating allowing semen drips to be collected; the vacuum method, using a turkey semen collector, inserted into the seminal canal; and the tube method, conducted by placing a test tube inside the seminal canal, allowing semen to enter by gravity. 2. For the funnel, vacuum and tube methods, respectively, average semen volume was 0.1 +/- 0.02, 1.12 +/- 0.22, and 0.58 +/- 0.13 ml, sperm concentration was 0.66 +/- 0.14, 2.35 +/- 0.26, and 2.13 +/- 0.27 x 10(9) cells/ml, and percentage of abnormal cells was 5.82 +/- 1.79%, 4.68 +/- 1.19%, and 7.09 +/- 1.72%. 3. Semen characteristics varied throughout the reproductive season reaching peak concentration in June-July. 4. The vacuum method proved to be the most efficient and was a low stress, restraint-free method for collecting ostrich semen.

Glucocorticoid administration during incubation: embryo mortality and posthatch growth in chickens.

The effects of glucocorticoids (GC) on embryonic mortality and posthatch BW were studied. Cortisol hemisuccinate or corticosterone in 0.1-mL vehicles were injected into the albumen of 7-d-old White Leghorn chicken embryos. Embryonic mortality rates and the age after injection at which death occurred were determined. When 0.02 to 20 microg cortisol per egg were injected in saline, total embryonic mortality rate increased in a doseresponse manner, with a median lethal dose (LD50) at 10 microg. Saline injection alone caused a similar mortality rate to that caused by injection of 2 microg cortisol (around 35%). However, whereas mortality among the cortisol-treated embryos was greatest on Days 16 to 18, most of the saline-treated embryos died around the time of injection. The lethal effect of corticosterone, which is endogenous GC in adult chickens, was compared to that of cortisol by injecting both in the same vehicle (a saline:ethanol mixture) and was found to be similar. However, when 2, 10, or 20 microg of corticosterone was injected in oil, mortality rates were lower than those caused by the matching doses of cortisol in saline, probably due to the lower diffusion rate of the steroid out of the oil carrier. Hatch weight was significantly lower in chicks treated with 10 and 20 microg cortisol, and BW of the latter was lower compared with control throughout the 3-mo observation. In conclusion, cortisol and corticosterone are equally active in causing embryonic mortality. Posthatch BW is affected only by GC doses that are equal to or greater than the LD50.

The relationship between neural alterations and behavioral deficits after prenatal exposure to heroin.

The present studies employ multitudinous approaches in order to overcome the methodological obstacles in the understanding of the relationship between neurochemical alterations and behavioral deficits induced by heroin during prenatal development. Mice were exposed prenatally to heroin via daily subcutaneous injections of 10 mg/kg, on gestation days 9-18. At age 50 days, the heroin-exposed offspring displayed behavioral deficits as assessed in the eight-arm and Morris mazes, pointing to possible alteration in the septohippocampal cholinergic innervations. Biochemically there was increased presynaptic activity of these innervations as attested to by the increased [3H]hemicholinium-3 (HC-3) binding sites and by K+-stimulated inositol phosphate (IP) formation. Postsynaptically, there was global hyperactivation along the different components of the nerve conduction cascade, including an increase in M1 muscarinic receptor Bmax, a general increase in G-proteins (GP) including the most relevant, G subtype, and an increase in IP formation and in basal protein kinase C (PKC) activity. However, there was desensitization of PKC activity in response to cholinergic agonist in the heroin-exposed offspring. Transplantation of normal embryonic cholinergic cells to the impaired hippocampus reversed the behavioral deficits and both the pre- and postsynaptic hyperactivity and resensitized PKC activity. To support and further strengthen the findings of the neural grafting study, correlation of the heroin-induced behavioral deficits with the biochemical alterations, done within individuals, was applied. The results showed high r values for IP formation, basal PKC, and PKC desensitization. The r values for HC-3 binding were statistically significant but relatively low. Taken together, the findings of the neural grafting and correlation studies bring us closer to understanding the relationship between the prenatal heroin-induced biochemical and behavioral changes. However, mammalian models possess the inherent methodological hindrances, stemming from possible maternal effects. To provide a control for these confounding variables, a chick embryo model was applied in which filial imprinting, a behavior related to a specific hyperstriatal nucleus, served as an endpoint. Heroin was administered to developing chick embryos by injecting the eggs (20 mg/kg) on incubation days (ID) 0 or 5. Prehatch exposure to heroin markedly diminished the ability for filial imprinting in the hatched chicks.

Short-term stress increases testosterone secretion from testes in male domestic fowl.

Prolonged stress inhibits the hypothalamus-pituitary-gonadal (HPG) axis and reduces plasma testosterone (T). However, enhanced secretion of luteinizing hormone (LH) and T has been documented during the initial stages of acute stress in mammals. This study assayed the effect of short-term stress on plasma T and corticosterone (B) in juvenile, pubertal, and adult White Leghorn cockerels. Stress was induced by brief physical restraint of caged juvenile (7 weeks), pubertal (17 weeks), and adult (40 weeks) cockerels, as well as 40-week-old adults reared together in a room lined with wood shavings (group reared). Blood was sampled immediately before restraint (0 time), at the end of a 10-min restraint period, and at 30, 60, and 180 min after 0 time. Restraint resulted in an initial increase in plasma T in all groups, along with a rise in B. Whereas B generally reached its peak level at the end of the restraining period, T peaked 20 min later. The maximum increase of T and B relative to prestress levels (T and B ratios) was similar in all groups, with median T ratio reaching 1.25-1. 5-about half that of the B ratio. Thus, the extent of T and B response to short-term stress was not influenced by basal levels of T, which were highest in adults, and basal levels of B, which were higher in caged adults than in group-reared adults. Injection of ACTH did not induce a greater increase in plasma T than in sham-injected controls. Further, the elevation of T in response to stress was extinguished in castrated adults, indicating that T is secreted from the testes rather than the adrenals in response to stress. When the same regime of blood sampling was applied to adults not subjected to restraint, the T ratio rose by up to 11 times. It can therefore be stipulated that T response depends on the type of stress applied, a factor that should be considered when investigating androgen levels in plasma.

The effect of pyrazine odor on body weight and the weight of various organs in chicks (Gallus gallus domesticus).

Embryonic and posthatch long-term exposure to the odor of 2-methoxy-3-isobutyl-pyrazine (2M3IP) was examined for its potential physiological consequences as reflected in changes in BW and organ weights in domestic chicks (Gallus gallus domesticus). Experiments were run from Day 1 of incubation to the age of 3 wk with a total of 360 fertile chicken eggs. The experimental design consisted of four treatment groups: PP chicks were exposed to 2M3IP during both incubation and posthatch rearing; PC chicks were exposed to 2M3IP during incubation only; CP chicks were exposed to 2M3IP during rearing period only; CC control chicks were not exposed to 2M3IP. Chicks were weighed immediately after hatch and at 3 wk of age, when they were necropsied. Various organs (thyroid, adrenal, testes, comb, liver, spleen, abdominal fat, and the bursa of Fabricius) were removed and weighed. Body weights of both sexes in the PP group were reduced. This reduction was significant in males relative to both CP and CC groups and in females only relative to the CP group. Effects of 2M3IP exposure on the examined organs were as follows: in males, adrenal gland weight significantly increased in the PP group vs all other groups. No weight differences were found between the other inspected organs among the four treatments. In females, comb weight significantly decreased compared with the rest of the groups when 2M3IP exposure occurred during incubation (PC). Further investigation is needed to study the mechanisms that underlie the differential effects of pyrazine odor on male and female chicks.

New monochromatic light source for laying hens.

Artificial illumination is an important factor in the management of layers. In this study, a new monochromatic light system was developed for egg layers. Prelaying pullets (Lohmann) were marked and housed in nine light and temperature control rooms (15 battery cages, 3 hens per cage; n = 45), divided into three light treatments: 0.1 and 0.01 W/m2 light intensity using light emitting diode (LED) lamps and 0.1 W/m2 using mini-fluorescent bulbs (PL) (control). In each of the LED rooms, three wavelengths were tested: 560 (n = 9), 660 (n = 9), 880 (n = 6), and 660 intermitted lighting (15 min light 45 min dark, 660IN) (n = 9). Birds were exposed to 12 h light and 12 h of darkness using PL lamps. At 21 wk of age, the light period was increased to 12.75 h by using 5.5 h of LED lamps and 7.25 of PL light source for Groups 1 and 2, the third group received 12.75 h of PL light. Until 28 wk of age, light hours increased by 0.5 h/w using LED light for Groups 1 and 2 and PL source for the third group, reaching 16 h of light at 28 wk of age. Egg production and feed consumption were recorded daily; egg components were recorded weekly for 10 mo. A significant reduction in egg production was observed in all 880nm groups; no differences in egg production and quality were found in the other groups. Feed consumption was significantly lower by 7% in all 0.01 W/m2 groups. We suggest that an important reduction in rearing costs of laying hens may be obtained by using this system.

Testosterone concentrations, testes weight and morphology of mule drakes (Muscovy drake x Khaki Campbell).

1. Mule ducks were produced by naturally mating Muscovy drakes and Khaki Campbell ducks. 2. Semen was collected from 6-month-old mule drakes via an artificial vagina. The fluid was clear without any spermatozoa or spermatids. 3. Testes from 27-week-old mule drakes were smaller in size than those of Khaki Campbell drakes but heavier than Muscovy males of the same age. Histological sections of these testes revealed that spermatogenesis was not complete. 4. Testosterone concentration in the mule drakes was higher than in Muscovy males but similar to Khaki Campbell drakes. 5. Mule drakes have strong sexual drives as a result of high concentrations of testosterone, but, because spermatogenesis is incomplete, their semen had no sperm.

Intermingling heavy and light strain chickens may cause social stress.

The present study examines the effects of intermingling day-old broiler chicks with 2-wk-old light strain chicks, on body weight, general activity, feeding behavior, feather condition, and heart size of the broilers. Fifteen groups of chicks (five for each treatment) were raised until 6 wk of age in 1 x 2 m experimental pens. Each group consisted of 10 broiler chicks in Treatment 1 (control pens), 8 broiler, and 2 light strain chicks in Treatment 2 (8:2), and 5 broiler with 5 light strain chicks in Treatment 3 (5:5). The feeding program consisted of a commercial starter ration (21% protein, 3,000 kcal ME/kg) for the first 4 wk followed by a finishing ration (18% protein, 3,150 kcal ME/kg). Feed and water were provided for ad libitum consumption. Body weight did not differ between Treatment 1 (controls) and the "intermingled" broilers. Feather condition was significantly poorer among the 5: 5 groups than in the controls. Heart weight (a possible indicator of chronic stress) in broilers of the 5:5 groups was significantly heavier than in the controls. No differences in the general activity parameters were found between broilers of the various treatments. Pecking at feed among broilers was significantly greater (P < 0.05) in the 8:2 groups than in both control and 5:5 groups. During the first 6 wk after hatching, intermingling broiler chicks with equal numbers of light strain chicks that are 2 wk older may lead to long-term chronic stress for the broilers.

An enrichment object that reduces aggressiveness and mortality in caged laying hens.

The effect on aggressive pecking activity and mortality by an environmental enrichment device was examined. In this study, 2955 White Leghorn chickens from three different lines were used in six separate experiments. Experiments were conducted with chickens during their first or second laying period. Half the cages in each experiment were equipped with colored key rings or an enrichment object manufactured by Gallus Ltd. (Israel). Experimental and control groups of cages were distributed in an alternate serial order for each experiment which lasted for 3, 4, 5, 8, 9, and 10 months. The enrichment devices significantly reduced aggressive head-pecking behavior and significantly decreased the mortality rate from 1.06% per month among the controls to 0.57% among the experimental groups.

Aggressive behaviour in immature captive Nile crocodiles, Crocodylus niloticus, in relation to feeding.

This study presents five aspects of aggressive behaviour in juvenile Nile crocodiles, Crocodylus niloticus, as observed in five cohorts of 6-18 month-old animals. During this period, the animals grew from a range of 35-55 cm, to a range of 65-115 cm. 1) Stock density related to aggression: decrease in density resulted in significant decrease in the frequency of agonistic events, with 0.64 events/100 crocodiles/min observed in a density of 6.7 crocodiles/m2, compared to 0.26 events/100 crocodiles/min observed in a density of 4.7 crocodiles/m2. 2) Aggression during feeding: in all five groups, there was a significantly higher level of aggression during feeding times. 3) Aggression related to body size: the largest crocodiles were the most aggressive group in agonistic events, mainly against the smallest ones. The largest group, the medium sized, was the least involved in agonistic events. 4) Aggression related to food preference: crocodile food preference was live fish > live chicks > dead fish > ground meat. Except for one food type (live chicks), a significant (p < 0.05) correlation was found between food preference and feeding related aggression in the prey diet groups. 5) Aggression related to an artificial selection for size: removal of the largest crocodiles (which formed 30% of the stock) from the population caused a dramatic decrease in all forms of aggressive behaviour.

Food preference, fish attractability and behavior manifested toward new feed in young Nile crocodiles, Crocodylus niloticus.

Food preference and fish-attractive parameters were studied on 1000 15- to 18-month-old Nile crocodiles, using two-choice preference tests. All three experimental groups preferred live fish over dead fish and live chicks, while ground meat was the last choice. As for fish attractiveness, motion, freshness, size, color and species were found as important parameters in the food-preference mechanism. When new feeds were presented to naive, ground-meat-eating crocodiles, we could find out the nature of innate and learned food recognition. Live fish, frogs and tadpoles were identified immediately as food, and the recognition of dead fish, chicks and anagmas required learning.

Fertile semen from 9-week-old chicks treated with tamoxifen.

White Leghorn male chicks were injected with 1 mg/kg BW of tamoxifen (an anti-estrogen) on alternating days between 2 and 9 wk of age. This treatment increased testes weight and induced semen production in response to the abdominal massage procedure. Insemination of laying hens with this semen resulted in hatching of live chicks from their eggs.

Population size, cage area, and dominance rank effects on productivity and well-being of laying hens.

The effect of two cage population sizes (four vs. six/cage) and two cage area treatments (316 cm2 vs. 406 cm2/bird) were compared in a nonconfounded design while maintaining feeder space constant (8.9 cm/bird) for egg production performances and behavioral and physiological indicators of well-being of laying hens. Egg production rates were determined for all members of each cage group (palpations at 48 to 50 wk) and on a cage group basis (20 to 60 wk). Heart weights, plasma corticosterone levels, durations of tonic immobility (TI), and plumage conditions were compared for top and bottom birds in the dominance ranks. Significant reductions in egg production were observed for low ranking hens in the high density (4 and 6/316-cm2) treatments. In addition, high ranking hens of the 6/316-cm2 treatment produced fewer eggs than high ranking hens in the 4/316-cm2 treatment. When high and low ranking individuals were housed in single-hen cages, egg production was improved relative to performances in the social environments. Heart weights of hens, as a percentage of body weight, were increased in the low ranking hens and for hens in the smaller cage size. Plasma corticosterone did not prove to be a useful indicator of well-being. Low ranking individuals had greater durations of TI but differences in feather condition were not detected. The results support the contention that appropriate population sizes and cage space allocations can be determined that will optimize the performance and welfare of layers in cage environments.

Effects on productivity and aggressive behavior of laying hens of solid versus wire cage partitions and bird density.

The effects of solid metal cage partitions or wire mesh cage partitions and two cage densities (5 or 7 birds/60.9 cm X 35.6-cm shallow cage) on production performance traits, aggressive behavior, and feather covering of White Leghorn layers were assessed from 20 to 60 wk of age. Type of cage partition had no significant effects on any of the traits measured. Higher cage density, however, was associated with significantly lower hen-day egg production, feed usage, final body weights, and feather covering. No differences were observed for egg weights, egg loss, mortality, or aggressive head pecking activity of birds housed in the two cage densities.

Application of the filial imprinting phenomenon to broiler chicks at a commercial farm.

Ten thousand broiler chicks on commercial farms in Israel were imprinted to blue and red plastic boxes (20 x 20 x 40 cm) containing loud speakers (8 omega, 12 W) equipped with a tape recorder, in which a classical music cassette had been placed. Upon reaching 3 wk of age, an attempt was made to move these chicks from the training area (A) to a new area (B) using the imprinting objects. This experiment was repeated four times: May, August and November of 1985, and in January 1986. During the warm months of May and August 30 to 60% of the experimental chicks followed the imprinting objects toward Area B. During the cold months and in all four repetitions with the controls, less than 5% of the flocks moved from Area A to Area B. Winter chicks may have been imprinted on brooder heaters. In all repetitions, most of the imprinted chicks distributed themselves equally over Area B 1 h after the doors between Areas B and A were closed. Controls, however, crowded around the door between Areas A and B resulting in the death of many chicks by asphyxiation. This study has shown that thousands of heavy strain chicks can be easily attached to an imprinting stimulus and it may be possible to apply this phenomenon for commercial purposes.

Testosterone and adiposity in the chicken: the effect of breed and sex.

The leaning role, previously suggested for testosterone in chickens, was tested in males and females of fatty and lean breeds. The breeds used were the White Leghorn (WL), of which the male is very lean, and the White Giant (WG) and the White Cornish X White Rock (WCWR), in which both sexes accumulate fat. Castration of WL males induced adiposity and replacement therapy with testosterone propionate (TP) reduced the fat to normal. However, in males of the fatty breeds, neither castration nor TP administration had any effect on adiposity. Similarly, long-term supplementation of a high dose of TP had no effect on the level of adiposity in females of both the heavy and the light breeds. Thus, the leaning effect found for testosterone in the WL male is not a general phenomenon in chickens but rather a specific response of the WL male.

Induction of precocious development of reproductive function in cockerels by tamoxifen administration.

To examine the effects of tamoxifen, a known estrogen antagonist in the chicken, two groups of cockerels were injected every other day from hatching until 7 weeks of age with 1 and 10 mg tamoxifen/kg body weight (BW), respectively. A third group was injected with 1 mg tamoxifen/kg BW every 3 days from 5 to 10 weeks of age. All groups treated with tamoxifen had increased testes weight, but BW and pituitary weights did not differ from controls. In contrast to controls, seminiferous epithelium of testes from treated cockerels showed spermatogenesis up to the spermatid elongation stage. We suggest that the antiestrogen effect of tamoxifen increased circulating LH, which stimulated testes growth and precocious spermatogenesis.

The gonadotropic-axis involvement in the course of the filial following response in the domestic fowl chick.

The detachment process of the domestic chick from its mother, or any other imprinting object occurs between the sixth and tenth week after hatching. The present study (Experiment I), examines whether the detachment process parallels endocrine events that precede prepuberty. Immediately upon hatching, groups of heavy strain chicks were imprinted to a colored foam rubber ball for 72 hours. The bond between these chicks and the imprinting object was then tested, and plasma LH and testosterone were assayed once a week until the chicks were 10 weeks of age; the sexual development of chicks of the same strain was studied at the same time. At the outset of the detachment period (5-7 weeks) an increase in plasma testosterone and a decrease in plasma LH was found. In addition, the comb and testes showed a definite weight increase while the bursa of Fabricius showed a significant decline in weight. In Experiment II, the beginning of the detachment process was induced by injecting 3 to 4 week old chicks with testosterone-propionate, estradiol-benzoate and 5 alpha-dihydrotestosterone. Our evidence therefore appears to demonstrate that testosterone and its metabolites induce the detachment process by the same mechanism used to stimulate sexual behavior in juvenile chicks.

An improved method for obtaining semen from Muscovy drakes and some of its quantitative and qualitative characteristics.

An improved method for obtaining semen from the Muscovy drake using an "artificial vagina" was developed and employed on a commercial scale. With such a procedure, the ejaculate volume was 1.12 +/- .85 ml, semen concentration was 1.35 +/- .43 X 10(9) cells/ml with 8.6 +/- 6.3% abnormal sperm cells. Average spermatozoal motility was graded as 3.59 +/- .93 on a scale of 0 to 5 and the initial pH was found to be 7.30 +/- .23 within 5 min of ejaculation.

Artificial insemination and natural mating in the crossbreeding of the Muscovy drake and the Pekin duck.

Artificial insemination and natural mating were used for the crossbreeding of the Muscovy drake with the Pekin duck in order to produce the Mule duck. An average fertility rate of 48% was reached by artificially inseminating twice a week. In small flocks, however, when the male to female ratio was 1:2.5 (or higher), natural mating yielded a fertility rate of 80%.