Male Ostriches Research Articles

Anatomical and morphometric studies on the axial skeleton of ostrich (Struthio camelus)

The present study showed a descriptive anatomical study of the parts of the axial skeleton in the ostrich (Struthio camelus) in addition to a morphometric study of each bone. We studied 7 male ostriches aged from 1 to 3 years with an average weight of 120.00 kg. The cranium exhibited two vast orbits supported by a sclerotic ring. Hyoid apparatus was fine delicate horseshoe-shaped and comprised Basihyale, Urohyale, and Cornu branchiale. Cornu branchiale were paired and long rod-shaped, consisting of a proximal bony part Ceratobranchiale and slightly curved distal cartilaginous process, the Epibranchiale located on either side of the hyoid apparatus. The whole vertebral column comprised 54 vertebrae, including 18 cervical vertebrae, 7 separated thoracic vertebrae, a synsacrum, and 9 separated caudal vertebrae. Atlas had a butterfly-shape with a narrow width and large vertebral foramen. Axis had a protruded dens with a rounded tip that arose from the cranial surface of the body for articulation with the Incisura fossae of atlas. Several Pneumatic foramina were found in the cervical vertebrae. The transverse foramen was found in all the cervical vertebrae except atlas. The ribs were nine pairs in number, the sternal ribs extended from the third to the seventh rib while the rest were asternal floating ribs. The sternum was a broad quadrilateral extensive bone, lacking the keel bone. It had dorsally several Pneumatic foramina.

RETROSPECTIVE STUDY OF MORTALITY IN CAPTIVE STRUTHIONIFORMES IN A FRENCH ZOO (1974-2015).

The husbandry and medical records, and necropsy reports, of 1,002 captive Struthioniformes that died at the Réserve Africaine de Sigean (France) from 1974 to 2015 were examined. The goal of this study was to determine the most common causes of mortality in ostriches ( Struthio camelus), emus ( Dromaius novaehollandiae), and American rheas ( Rhea americana), in order to highlight common causes of mortality, as well as the influence of age, gender, and rearing methods on mortality. The most prevalent cause of mortality was pathology of digestive origin in the neonates of all three species, especially yolk-sac infections, which accounted for 41% of all deaths in this captive neonate population and was especially prevalent in hand-reared neonates. Other causes included musculoskeletal disorders in emus (particularly hand-reared) and rheas; trauma in neonate ostriches, mainly due to crushing by parents; leg deformities in emu chicks and juveniles; general sepsis in hand-reared ratite chicks due to a chlamydiosis outbreaks (1989-1990); trauma by conspecifics in subadult ostriches and emus; stress myopathy in subadult rheas, particularly after introduction to a new enclosure; evisceration inflicted by herbivorous enclosure mates on adult male ostriches; fatal peritonitis following salpingitis in adult female ostriches; and death associated with ocular disorder in adult male emus. Although this study was conducted at one institution, and its results reflect this zoo's management and zootechnical practices, its findings could well have implications for management practices involving other captive Struthioniforme populations.

Histological, Histochemical and Ultrastructure Studies on the Ostrich Pancreas (Struthio camelus)

This work aimed to discuss the histological, histochemical and ultrastructure of the ostrich pancreas. Specimens were collected from eight adult apparent healthy male ostriches. The specimens immediately immersed in 10 % neutral buffered formalin and Bouin,s solution. Tissue sections were prepared and stained for further examination. The histological examination demonstrated that the ostrich pancreas surrounded by a thick connective tissue capsule which gave septa to the parenchyma and divided it into numerous pancreatic lobules. The parenchyma composed of exocrine and endocrine parts. The exocrine part formed by acini, the acinar cell was large pyramidal, with a large rounded vesicular nucleus. Its apical part had fine deeply stained zymogenic granules. The endocrine portion was formed by beta, alpha and mixed islets. Ultrastructurally, the acinar cells forming the pancreatic acini appeared pyramidal having a basally large vesicular nucleus with large spherical and electron dense nucleoli. Its zymogene granules were spherical and electron dense. The beta cells were large ovoid or polygonal contained electron dense secretory granules with the presence of halo zoon between its limited membrane and the content. Alpha cells are elongated or polygonal contain electron dense spherical secretory granules with ill distinct space between the limited membrane and its content. Delta cells appeared oval or triangular having spherical electron dense granules its limited membrane closely adhere to its content. There were a different histochemical reaction to acid phosphatase, alkaline phosphatase, ATPase and succinic dehydrogenase in the acinar cells and in the pancreatic islets.

Sex-related differences of bone properties of pelvic limb and bone metabolism indices in 14-month-old ostriches (Struthio camelus)

ABSTRACT1. Sex-related differences of long pelvic limb bones and serum bone metabolism indices were evaluated in 14-month-old female (N = 7) and male (N = 7) ostriches of similar body weights.2. Densitometric parameters of femur, tibia and tarsometatarsus were determined using quantitative computed tomography (volumetric bone mineral density, calcium hydroxyapatite density and mean volumetric bone mineral density) and dual energy X-ray absorptiometry (bone mineral density and bone mineral content) methods. Geometrical parameters such as cortical bone area, cross-sectional area, second moment of inertia, mean relative wall thickness and cortical index were determined in the midshaft of bones. Mechanical properties of bones (maximum elastic strength and ultimate strength) were evaluated using three-point bending test. Serum concentrations of free amino acids, osteocalcin, N-terminal propeptide of type I procollagen, C-terminal telopeptides of type II collagen and total antioxidative capacity were also determined.3. Bone weight and relative bone weight of all bones were significantly higher in males than in females. Significantly lower values of trabecular bone mineral density and calcium hydroxyapatite density were found in the trabecular bone of tibia in males. The highest number of the sex-related differences was observed in the tarsometatarsus where bone length, bone mineral content, cortical bone area, cross-sectional area and ultimate strength were higher in males. Serum concentrations of taurine, hydroxyproline, valine and isoleucine were significantly higher in males.4. Higher loading of the tarsometatarsus in comparison to femur and tibia may be an important factor interacting with sex hormones in regulation of bone formation and mineralisation processes. Sex-related differences of bone properties were associated with increased serum concentration of selected amino acids in males.

Predicting ejaculate quality and libido in male ostriches: Effect of season and age

The success of artificial breeding program depends largely on the reproductive performance of males. Male performance can vary with season and age impacting on quality and quantity of semen collected for artificial insemination purposes and therefore fertility of inseminated females. We examined variation in semen output and male libido of seven male ostriches (aged 2–5 years) over a period of 24 months. We collected ejaculates using a dummy female and measured semen characteristics (ejaculate volume, sperm concentration, number of spermatozoa per ejaculate, sperm motility and morphology) and male libido (willingness to mount the dummy). A total of 1006 ejaculates were collected. Across months, the volume of semen (mean±SEM) ranged from 1.03±0.12mL to 1.85±0.07mL, the sperm concentration from 3.21±0.12×109/mL to 4.16±0.74×109/mL, and the number of spermatozoa from 3.42±0.28×109 to 7.66±0.47×109. The largest volume of ejaculates and the highest number of sperm were collected in spring. Ejaculates with higher number of normal sperm were also collected in spring–early summer, whereas ejaculates with higher numbers of live abnormal and dead sperm were collected in winter. Sperm motility was relatively constant over months, despite a reduction in summer (January–February), while male libido peaked in winter (June–July) and spring (October–November). Furthermore, we observed high individual variation between males for all variables tested, except for motility. These results indicate that collections conducted in spring yield higher number of spermatozoa, when the libido of males is also at a maximum. Therefore in this species seasonal variation in semen quality should be considered in breeding programmes by artificial insemination to maximise fertility.

Effect of canola oil on blood lipid in ostriches (Struthio camelus)

In order to study the lipid profile of ostriches in relation to diet, 6 blue-neck male ostriches (Struthio camelus) were used and fed with 3% canola oil supplement on diets adlibitum consisting. In the morning, after about 12 h of fasting, blood was collected from the wing vein on days 0 and 60. Blood samples were collected from ostriches to measure levels of the following lipid parameters include high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL), triglyceride, total cholesterol were determined. Results showed that from days 0 to 60, LDL and total cholesterol levels increased significantly, whereas HDL, VLDL and triglyceride didn't change.

بررسی اثر جنس و شرایط کشتار بر راندمان، ترکیب وزنی و میزان افت در مراحل مختلف پس از کشتار لاشه شترمرغ ور ارزیابی اقتصادی آن

تعیین ترکیبات وزنی بدن دام به خصوص شترمرغ به علت نوپا بودن صنعت پرورش آن در ایران و همچنین بررسی اثر جنس و شرایط کشتاری بر کیفیت لاشه از جایگاه ویژه ای در صنعت گوشتی برخوردار است. بر اساس نتایج پژوهش حاضر، میزان راندمان گرم شترمرغ 93/55درصد بوده که از راندمان سرد (70/54درصد) بیشتر می باشد ) 05/0 (p>. خون، پر و پوست بیشترین و سر کمترین جزء ترکیبات وزنی شترمرغ را تشکیل داد و اثر جنس بر ترکیبات وزنی بدن غیرمعنی دار به دست آمد. میزان افت سرد کردن لاشه های شترمرغ حدود 2/2 درصد بود که در جنس نر و ماده تفاوت معنی داری با هم نداشت ) 05/0 (p>. میانگین افت خونابه در روز اول پس از کشتار 52/1درصد و در روز هفتم 68/1درصد بود. مقدار افت پخت به طور متوسط در جنس نر 85/31درصد و در جنس ماده 55/33درصد محاسبه گردید. همچنین میانگین افت پخت در نمونه های شترمرغ شوک دیده 30/33درصد و در نمونه های بدون بیهوشی 10/32درصد اندازه گیری شد. علیرغم افزایش افت خونابه و افت پخت طی مدت نگهداری گوشت تا 14 روز، اثر معنی داری از زمان، جنس و شرایط کشتار در هر دو میزان افت مشاهده نگردید ) 05/0 (p>.

Sex-related differences of morphometric, densitometric, and geometric parameters of tibia and tarsometatarsal bone in 14-month-old ostriches (Struthio camelus)

The aim of the current study was to investigate basic morphometric, geometric, and densitometric parameters of tibia and tarsometatarsus in 14-mo-old male and female ostriches, and interrelationships between these parameters. The study was conducted on 20 tibiae and 20 tarsometatarsal bones of the left pelvic limb derived from 20 healthy 14-mo-old ostriches (Struthio camelus): 10 males and 10 females. The following parameters were determined using peripheral quantitative computed tomography: bone mineral content (BMC), volumetric bone mineral density (vBMD), cortical content (CRT_CNT), cortical density (CRT_DEN), trabecular content, trabecular density (TRAB_DEN), bone area (TOT_A), trabecular area (TRAB_A), cortical area (CRT_A), cortical thickness (CRT_THK_C), periosteal circumference (PERI_C), endocortical circumference (ENDO_C), and strength-strain index (SSI) in the metaphysis and diaphysis of the bones. Statistical evaluation of the obtained results was performed using Student's t-test, and the Pearson correlation coefficient between the investigated parameters was determined. The obtained results have shown significant differences in proximal metaphysis between males and females when evaluating such parameters as CRT_DEN, TOT_A, TRAB_A, PERI_C, SSI in tibia (P < 0.05), and BMC, vBMD, TRAB_DEN, CRT_CNT, TOT_A, TRAB_A, cortical area, PERI_C, ENDO_C, SSI in tarsometatarsus (P < 0.05). Significant differences between the 2 sexes were found in all the investigated parameters of diaphysis of tibia, except for CRT_DEN and ENDO_C (P < 0.05). Significant positive correlations between BW and bone weight were found (P < 0.05). Furthermore, numerous correlations of morphometric, geometric, and densitometric parameters of metaphysis and diaphysis of the tibia and tarsometatarsus were stated (P < 0.05). In conclusion, the present investigation demonstrated sex-related differences in morphometric, densitometric, and geometric properties of tibia and tarsometatarsus in 14-mo-old ostriches. Numerous correleations observed between the investigated parameters have shown that ostrich tibia and tarsometatarsus may present a valuable model for further studies on bone tissue metabolism regulation in breeding birds.

Morphological Study and Determination of M/E Ratio in the Bone Marrow of the Male Adult Ostriches (Struthio camelus)

Normal haematopoiesis, cellular components and M/E ratio in the bone marrow of the male adult ostriches (Struthio camelus)were studied. Bone marrow samples were collected from the proximal tibiotarsus bone of 10 healthy adult ostriches. The bone marrow smears were stained using the Giemsa stain. The results indicated that the development and formation of blood cells in the bone marrow of partridge were similar to other birds. The morphology of the cells was similar to chickens, ducks, quail, and black-head gull. The mean myeloid/erythroid (M/E) ratio was 1.02, the mean erythroid percentage was 47.38%, the mean myeloid percentage was 48.15%, the mean thrombocytic percentage was 3.52% and the mean percentage of all other cells percentage was 0.99%

Prosopis farcta beans increase HDL cholesterol and decrease LDL cholesterol in ostriches (Struthio camelus)

Ten blue-neck male ostriches (Struthio camelus) were fed Prosopis farcta beans throughout a 30-day experiment. Blood samples were collected from ostriches on days 0 and 30 to measure levels of high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglyceride, total serum protein, albumin, globulin, cholesterol, calcium, inorganic phosphorus, the activity of aspartate aminotransferase, alanine aminotransferase, and γ-glutamyl transferase (γ-GT). From days 0 to 30, HDL cholesterol, total protein, and globulins levels increased significantly whereas LDL cholesterol, inorganic phosphorus, and γ-GT activity decreased significantly.

Rhodanese activity in different tissues of the ostrich

1. The purpose of this investigation was to determine the activity, and compare the pattern of distribution, of rhodanese (thiosulphate: cyanide sulphurtransferase, EC. 2.8.1.1) in different tissues of male and female ostriches. 2. Tissue samples from male and female Blue Neck ostriches were assayed for rhodanese activity by the determination of thiocyanate formed by the action of the enzyme on thiosulphate and KCN. 3. Rhodanese was present in all tissues, and the highest activity was observed in the kidney and liver. Other tissues which contained significant activities of rhodanese were the duodenum, pancreas, heart, caecum and rectum. 4. Unlike other birds, the proventiculus does not appear to have an important role in cyanide detoxification in ostrich and, like mammals, the kidney and liver perform this function. 5. The results suggest that the main organs harbouring high rhodanese activity in the ostrich are associated with sites likely to be required in rhodanese mediated cyanide detoxification.

Diurnal variations in serum biochemical parameters and their correlations with thyroid hormones in ostrich chicks (Struthio camelus)

The present study aimed to examine variations in serum biochemical parameters to provide data about the diurnal variation of biochemical parameters in ostriches. This study was performed using blood samples from eight healthy male ostriches, (3 months old), which were in good condition and clinically normal. Diurnal variation of serum biochemical parameters was determined by daily blood collections over 9 days in summer at the School of Veterinary Medicine, Shiraz University. In serum samples nonelectrolytes (total protein, albumin, glucose, cholesterol, triglyceride, HDL cholesterol, creatinine, urea nitrogen, and uric acid), electrolytes (calcium, inorganic phosphorus, sodium, and potassium), enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and creatin kinase (CK)), and hormones (triiodothyronine (T3) and thyroxine (T4)) were measured by validated standard methods. Most of the study variables showed no significant variations during the study period. However, for blood urea nitrogen, glucose, ALT, K, HDL cholesterol, and CK, significant changes were observed. Correlation coefficients showed significant association of T4 with Na (r = 0.38, P = 0.001), glucose (r = −0.25, P = 0.03), calcium (r = −0.28, P = 0.02), uric acid (r = 0.26, P = 0.03), and creatinine (r = −0.25, P = 0.03). Regarding T3, significant correlation with Na (−0.27, P = 0.02) was observed.

Anatomic Study on the Main Male Reproductive Organs of Ostrich

In order to promote the application and extension of artificial insemination technique in ostrich industry, we carried out this research on the structure of male ostrich reproductive organs. The results of systematic anatomic observation on reproductive organs of 53 obsolete male ostriches show that: (1) For ostrich above 2 years old, the testis tends to enlarge in breeding season and shrink in ceased period. When they are mature, the color turns from milk white into the milky grey. With an average body weight 135.6±6.50kg, the ostriches have their testis 678.7±20.44g in weight and 9.6±3.43cm in length on average. (2) For 1-year-old ostriches before sexual maturity, the penis is smaller and short, shaped as a light pink bar. After sexual maturity, the testis shows a tendency of enlarging in breeding season and shrinking in ceased period. For ostrich above 2 years old, the weight of penis is 870±45.63g on average and the length is 30.1±12.45cm on average. The depth of ejaculatory groove is 19.18±3.58mm on average. (3) In cloacae, there is a less cyst cavity at the base of penis. In cyst cavity, there are two 5mm long ejaculatory mastoid processes, which have tubule connected to testis respectively. By systematic anatomic observation, constructions of ostrich reproductive organs were carefully observed, thus the further research on artificial insemination technique in ostrich could be promoted.

Twice daily collection yields greater semen output and does not affect male libido in the ostrich

The success of an artificial insemination program in ostriches is highly dependent on the yield of viable semen. We, therefore, tested how semen output is affected by three different collection frequencies: once every 2d (48h interval), daily (24h interval), and twice a day (6h interval). Ejaculates were collected from seven male ostriches (aged 2–4 years) for 10 consecutive days using the dummy female method. We assessed semen characteristics (sperm motility, volume, concentration, number of sperm per ejaculate and sperm viability) and male libido (the delay between the presentation of the dummy and ejaculation, and the willingness to mount the dummy). The total daily output of semen and the number of sperm were greater at the 6h collection interval than at the 24h or 48h interval while sperm motility and viability were not affected. At the 6h interval, the number of live normal sperm increased over the treatment period while the number of live abnormal sperm was reduced. Furthermore, the time that males took to mount the dummy and their willingness to copulate with the dummy were unaffected by collection frequency. Across males we observed great individual variation in both semen characteristics and libido suggesting there is the potential to increase the efficiency of semen collection by selecting superior males. These results indicate not only that two collections per day yield maximum semen output and may improve semen viability, but also that quantifying variation between males may help further increase semen collection efficiency.

Male coloration reveals different components of immunocompetence in ostriches, Struthio camelus

It has been suggested that secondary sexual ornamentation signals male ability to resist infections, as only high-quality individuals are able to invest both in high immune defence and elaborate ornament expression. Such ornaments could thus serve as indicators of male quality and could be used by females in choosing mates. Ostriches are sexually dimorphic with regard to coloration of their feathers, bill, neck and legs, and have a promiscuous mating system, with a high degree of reproductive skew, particularly in males. We investigated the relationship between the coloration of the feathers, bill, neck and legs of 15 male ostriches, maintained in a breeding flock, and the cell-mediated (measured using a phytohaemagglutinin (PHA) injection) and humoral components of their immune systems, as well as their heterophil:lymphocyte ratio. We found that male responses to PHA injection and humoral responses to tetanus were predicted by leg coloration, humoral responses to diphtheria were predicted by white feather coloration, and the heterophil:lymphocyte ratio was related to bill coloration. These traits, which relate to male immune capacity, are exposed during male–male interactions and courtship display, so we suggest that these visual cues could provide valuable information on male quality to females (as well as rival males), forming the basis of mate choice in this species.

Investment in eggs is influenced by male coloration in the ostrich, Struthio camelus

Life history theory predicts that females should modify their investment in a particular breeding attempt according to the likelihood of its success, as the investment of females in reproduction is typically higher than that of males. The ostrich mating system is promiscuous, and is thus a particularly interesting one in which to investigate differential investment by the sexes. To date, there has been no evidence that female ostriches discriminate between males as potential mates, but the degree of dimorphism in this promiscuous species and the variation in chick size within clutches suggest that differential maternal investment is likely. We investigated the relationship between egg mass and coloration of the feathers, bill, neck and legs of 15 male ostriches, maintained in a breeding flock at an ostrich farm in South Africa. Paternity was determined using microsatellite markers. We found that the colour of the neck, white and black body feathers, and the brightness of black feathers, predicted egg mass. These traits are exposed during the male courtship display, so we suggest that these visual cues influence the degree of maternal investment in eggs through their influence on female perception of mate quality.

Semen collection in the ostrich (Struthio camelus) using a dummy or a teaser female

1. We investigated the feasibility of training male ostriches to ejaculate into an artificial cloaca (AC) using a teaser female or a dummy. 2. Male ostriches develop desirable behaviour patterns that allow them to be trained to the teaser and the dummy female. Training success can be high as both methods rely on natural stimulation and voluntary ejaculation into the AC provided suitable individuals are identified. 3. The key factors to successful training appear to be: the teaser method—temperament of male ostriches, the crouching behaviour of the female ostriches for the semen collector and acceptance of the collector by the male; dummy method—courtship of humans, learning ability of ostriches to habituate and then to mount a dummy. 4. Both methods are reliable, yield ejaculates of high quality and give reproducible results. The ejaculate volume was 1·09 ± 0·13 ml, the concentration of spermatozoa 4·21 ± 0·27 × 109/ml, the total number of spermatozoa 4·67 ± 0·62 × 109 and motility 4·3 ± 0·1. 5. Commercial ostrich production that relies on natural mating can take advantage of those methods to develop artificial insemination technologies.

The effects of dietary energy and protein concentrations on ostrich skin quality

The effects were investigated of energy and protein concentrations (with associated amino acid concentrations) in ostrich diets on leather quality of the skins of 50 ostriches. Energy concentrations were 9.0, 10.5 and 12.0 MJ ME/kg diet and protein concentrations were 130, 150 and 170 g/kg diet. The physical leather parameters that were assessed included tensile strength, elongation, slit tear strength and skin thickness. All traits were assessed in samples taken parallel or perpendicular to the spine in the butt region of the slaughter bird. The raw skin weights of ostriches consuming the diets with energy concentrations of 10.5 and 12.0 MJ ME/kg diet were respectively 19.4 and 21.8% heavier at slaughter than those of their contemporaries on the 9.0 MJ ME/kg DM diet. A corresponding trend was found for trimmed skin weight, and the increase in skin weight with diets higher in energy exceeded 10%. Differences between skin area means only approached significance, with a tendency to increase with an increased energy concentration. Leather thickness taken parallel to the spine was increased by 13% in the diet containing 12 MJ ME/kg diet, compared to the diet containing 9.0 MJ ME/kg. Dietary protein concentrations failed to influence skin weight, skin area or any of the physical leather properties. The skins of male ostriches were thicker than those of females. The study suggested that the lowest levels of energy and protein supplied, were sufficient to prevent a decline in physical leather quality. South African Journal of Animal Science Vol. 36(1) 2006: 40-44

Growth in the ostrich (Struthio camelus var. domesticus)

ABSTRACTThe use of the ostrich as a livestock animal necessitates an understanding of its ability to utilize specific nutrient requirements if efficient growth is to be realized. Male ostriches may have to be raised separately as they grow faster; they require higher protein diets and are more efficient feed converters for longer periods than female ostriches. Male ostriches exhibit slightly faster maturation rates than female ostriches. The corresponding age at which maximum growth is attained is 181 days for male ostriches and 199 days for female ostriches. The growth curve of ostriches is sigmoid and asymptotic. Body mass reached in 1 year is approximately 104 kg. The metabolic age of ostriches at hatching is approximately 13.7 days. Feed conversion has an impact on growth. The ostrich chick (aged &lt;2 months) has a high feed conversion to body mass ratio of 2:1, which requires very accurate and careful management of chick nutrition.

Semen collection, examination and spermiogram in ostriches.

The level of fertility in the male ostrich exerts considerable influence on the efficiency of the fertilization procedure, and thus also on reproductive performance. The determination of the reproductive capacity is of particular interest with regard to the selection of single individuals for optimizing reproduction ratios. Although the breeding and raising of ostriches has become increasingly important in many countries, little research has been completed on reproductive parameters and factors that may possibly influence them. This study presents observations made concerning the quantity and quality of sperm as found in the spermatological testing of 411 ejaculate samples taken from male ostriches on two farms in Namibia. The semen volume varied between 0.1 and 1.5 ml (mean, 0.64 ml). Normal ejaculate colours ranged from white to ivory; the consistency ranged from thin creamy to viscous. The measured pH values lay between 6.4 and 8.0 (mean, 7.3). Microscopic investigations revealed sperm concentrations of 8.9-78.1 million/microl and individual sperm motility from 42 to 96% (mean, 78%). No mass motility was detectable in 42% of the ejaculates; weak mass motility was found in 46%, and clear mass movements were to be found in only 12% of samples. Regarding the morphology of the sperm, 5 to 26% were abnormal (mean, 17%) and 4 to 28% (mean, 20%) were dead. Seasonal patterns of sperm concentration and the influence of frequency of semen collection were investigated in a group of 56 healthy male ostriches. Peak sperm concentrations were found at the beginning of the breeding season in spring; the lowest values were found at the end of the breeding season in autumn. The highest quality ejaculate was obtained from those males whose semen was collected once a week. The results of this study provide fundamental data for the establishment of minimum quality requirements for ostrich sperm to be met by individuals receiving certification as breeding animals and for the selection of suitable males for use in artificial insemination.