Genetic parameters and correlations for behavioural response traits towards humans in South African Black ostriches.

1. The aim of this study was to estimate heritability and genetic correlations, first among behavioural responses of juvenile South African Black ostriches towards humans and secondly with slaughter weight and skin traits.2. Behavioural traits, such as willingness of the birds to approach humans, keeping a distance from the human observer and allowing touch interactions by a human were recorded (n = 1012 birds). In addition, slaughter weight, skin size, scores for nodule size, nodule shape and the presence of hair follicles were recorded.3. Single- and multi-trait animal model analyses performed on the data using ASReml4 revealed high heritability estimates of 0.44 for allowing touch interactions and 0.48 for both willingness to approach and keeping a distance from the human observer. In addition, significant genetic correlations among behavioural response traits were estimated, ranging from -0.99 between keeping a distance and willingness to approach the human observer, to 0.87 between allowing touch interactions and willingness to approach the human observer.4. In contrast, genetic correlations of behavioural response traits with most slaughter and skin traits were low, variable, and not significant. The exception was hair follicle score, which appeared to be unfavourably correlated with key behavioural traits.5. This study suggested that the temperament of ostriches could be improved by selection of birds that demonstrate willingness to associate with humans without compromising slaughter weight or skin traits.

Partial Amputation of a Nonreducing Prolapsed Phallus in an Ostrich (Struthio camelus).

A 19-year-old male ostrich (Struthio camelus) was referred to a veterinary teaching hospital (São Paulo State University, Botucatu, Brazil) due to a 6-month history of recurrent prolapse of the phallus. On physical examination, 2 ulcerative wounds were present on the phallus, as well as caseous plaques and myiasis. Conservative treatment resulted in improvement but prolapse of the phallus remained. Thus, a decision was made to perform a partial phallectomy. The surgery was successful and no postoperative complications occurred. When the ostrich was reexamined 6 months postsurgery, the ostrich was alert, in good health, and the surgical site completely healed. The owner verbally reported no recurrence of the phallus prolapse 1 year after surgery.

Subtotal Cervical Esophagectomy and Anastomosis in an Ostrich (Struthio camelus domesticus).

An adult, female, captive ostrich (Struthio camelus domesticus) was referred to a veterinary teaching hospital for a 2-week history of lethargy and a mass effect in the proximal cervical region. Physical examination revealed a fistula in the middle cervical esophagus surrounded by devitalized and necrotic tissue; feed material was found leaking from the site. Cervical radiography identified an esophageal stricture with anterior dilation due to the accumulation of feed. After receiving supportive care for 48 hours, the patient's overall status improved, allowing partial esophagectomy and resection of the affected tissues with end-to-end anastomosis. Postoperative management included fasting for 24 hours, followed by the administration of a liquid hand-rearing formula prepared with commercially available ostrich feed and administered via a feeding tube for 15 days. Proper healing of the surgical site was confirmed by esophagoscopy using a flexible endoscope 17 days after surgery. The ostrich was discharged after 27 days, with no complications recorded within the 180 days of the follow-up period. Partial cervical esophagectomy with end-to-end anastomosis along with pre- and postoperative management provided a successful outcome for the treatment of a fistulated esophageal stricture in a captive ostrich, resulting in full recovery without surgical complications.

Investigation of egg production curve in ostrich using nonlinear functions.

In most countries, ostrich farming is considered a developing branch of the efficient poultry industry. The profitability of ostrich farm requires specific consideration of productions features such as the female fertility, egg production, hatchability, and growth performance. Hence, this study aimed to fit nonlinear functions to describe the ostrich egg production pattern to achieve the most appropriate and recommendable mathematical function for future studies. For this purpose, 14,507 daily records of 184 female ostriches in 5 production seasons (periods) during 2016 to 2021 were used. Five nonlinear functions including Incomplete gamma (Wood function), Corrected gamma (McNally), nonlinear Logistic (Yang), Logistic (Nelder), and Lokhorst were fitted for modeling the egg production curve in ostrich. The goodness of fit criteria's including Mean Square Error (MSE), Likelihood Ratio Test (LRT), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) were used to evaluate and selection of the best function. The results indicated that the Wood and the McNally functions with a slight difference in all fitting criteria were the best-fitted functions and the Yang function with the highest values of MSE, LRT, AIC, BIC, were the most inappropriate function to describe the ostrich egg production curve. The McNally and the Wood can be recommended as appropriate functions to describe egg production during 5 production seasons in the studied ostrich flock.

Experimental evidence that group size generates divergent benefits of cooperative breeding for male and female ostriches.

Cooperative breeding allows the costs of parental care to be shared, but as groups become larger, such benefits often decline as competition increases and group cohesion breaks down. The counteracting forces of cooperation and competition are predicted to select for an optimal group size, but variation in groups is ubiquitous across cooperative breeding animals. Here, we experimentally test if group sizes vary because of sex differences in the costs and benefits of cooperative breeding in captive ostriches, Struthio camelus, and compare this to the distribution of group sizes in the wild. We established 96 groups with different numbers of males (1 or 3) and females (1, 3, 4, or 6) and manipulated opportunities for cooperation over incubation. There was a clear optimal group size for males (one male with four or more females) that was explained by high costs of competition and negligible benefits of cooperation. Conversely, female reproductive success was maximised across a range of group sizes due to the benefits of cooperation with male and female group members. Reproductive success in intermediate sized groups was low for both males and females due to sexual conflict over the timing of mating and incubation. Our experiments show that sex differences in cooperation and competition can explain group size variation in cooperative breeders.

Being a parent is hard work. The unrelenting demand for food and protection is exhausting. Now imagine being a parent on the hot African savannah. Food and water are scarce, and whenever you leave your offspring, they overheat, or something eats them. This is the reality for ostriches. They, like humans, cope with the challenges of parenthood by sharing childcare responsibilities. Ostriches live in groups, breed in a communal nest, and take it in turns to incubate their eggs. This helps to maximize the survival of their offspring, but it has its downsides. The bigger a group gets, the more its members have to compete over mates and space for their eggs in the nest. The balance between cooperation and competition should, in theory, result in one 'optimal' group size. But this pattern does not seem to hold true: in the wild, ostrich families vary wildly in size and composition. To find out why, Melgar et al. set up dozens of groups of breeding ostriches and gave them different opportunities to cooperate. For males, there was one group size that maximized the number of offspring they produced (reproductive success): a single male with four or more females. Males did not benefit much from cooperation, and suffered greatly from competing with other males for mates. For females, however, the story was different. They benefited much more than males from cooperation and did best in bigger groups where they could share egg care with other individuals. Middle-sized groups were not good for either sex because reproduction was hard to coordinate: males continued to pursue copulations after females had initiated incubation, resulting in eggs being exposed and broken. The different priorities of males and females explain why there is no single optimal group size for ostriches. How groups balance competition and cooperation is a fundamental question in biology. Why do some organisms prefer to live alone, while others thrive in large groups? Understanding more about the balance of priorities within a group could hold the answers. It could also help to inform conservation work and animal breeding by showing how different social pressures influence breeding success.

Mass Sperm Motility Is Correlated to Sperm Motility as Measured by Computer-Aided Sperm Analysis (CASA) Technology in Farmed Ostriches.

Semen analyses have gained momentum in various livestock industries. However, in farmed ostriches, semen analysis is still in its experimental stage, and males are not screened for sperm quality before breeding. This study investigated the correlations between computer-aided sperm analysis (CASA) technology and the traditional, yet affordable, mass sperm motility score. Semen was collected from nine South African Black ostrich males (mean age ± SD: 5.25 ± 1.21 years), using the dummy female method for 5 consecutive days monthly, for 8 months. Mass sperm motility scores were recorded on a scale of 1−5 (1: little to no sperm movement; 5: rapid sperm movement). The CASA traits recorded were: total motility (MOT), progressive motility (PMOT), curve−linear velocity (VCL), straight-line velocity (VSL), average path velocity (VAP), amplitude of lateral head displacement (ALH), linearity (LIN), straightness (STR), wobble (WOB), and beat-cross frequency (BCF). The results revealed positive correlations between mass sperm motility and PMOT, MOT, VCL, and VAP ranging from 0.34 to 0.59 (p < 0.0001). In contrast, negative correlations were recorded between mass sperm motility and LIN, STR, and BCF, with correlations ranging from −0.20 to −0.39 (p < 0.0001). VSL, ALH, and WOB were not correlated to mass sperm motility (p > 0.05). Ostrich farmers may thus be able to evaluate sperm motility reliably and potentially select breeding males by using the affordable mass sperm motility scoring method. Determining the correlation between these methods and fertility after artificial insemination or natural mating is however needed.

Minimum sperm dose for optimal fertility after artificial insemination in ostriches.

Artificial insemination (AI) in ostriches may present potential solutions to high proportions of infertile eggs commonly recorded on commercial farms and assist in reducing the number of males for breeding purposes thereby leading to a more economical and efficient farming system. Although non-invasive methods to collect semen and to artificially inseminate female ostriches have been developed, the insemination dose for maximum fertility of eggs remains unknown. This study was thus conducted to determine the minimum sperm dose that would promote fertility of eggs following AI in female ostriches. A total of 22 South African black ostriches (7 males and 15 females) aged between 2 and 9 years old were used. Semen samples were collected using the dummy female method and diluted 1:4 (semen: diluent) with an ostrich specific semen diluent. Females were inseminated with various sperm doses of diluted semen from the same male three times a week, every second day resulting in a total sperm dose of A: <2.5 × 109, B: 2.5-5 × 109, C: 5-7.5 × 109 and D: 7.5-9.6 × 109 sperm/week. Eggs produced after insemination were opened to determine the fertilization status of the germinal disc (GD) with an unaided eye. The fertile period was then calculated as the number of days fertilized eggs were laid after the last AI. Furthermore, the number of sperm trapped in the outer perivitelline membrane (spermOPVL) above the GD region was counted under fluorescent light, following staining with 4',6-diamidino-2-phenylindole to determine the rate of sperm loss and the number of days up to when the last egg containing sperm was laid. On average, a mean (±sd) of 35.34 ± 25.72% eggs produced after AI were fertilized. Fertility was lower (mean ± se) when sperm dose A was used (6.71 ± 9.40%), as compared to sperm dose B (46.01 ± 6.71%), C (37.34 ± 6.60%) and D (37.75 ± 8.36%) (P < 0.05). No significant difference was recorded in the latter three doses (P > 0.05). Furthermore, the length of the fertile period and the rate of sperm loss did not differ significantly between sperm doses (P > 0.05). Hence, a sperm dose of between 2.5 and 5 × 109 sperm/week is recommended to optimize fertility after AI in ostriches, as increasing the sperm dose would not benefit fertility. Further studies are, however, needed to determine the frequency of insemination that would maintain fertility throughout the breeding season as well as hatchability of eggs laid after AI.

A new approach of immunotherapy against Crotalus snakes envenoming: ostrich (Struthio camelus) egg yolk antibodies (IgY-technology) / Un nuevo enfoque de inmunoterapia contra el envenenamiento de serpientes Crotalus: anticuerpos de yema de huevo de avestruz (Struthio camelus) (tecnología IgY)

Abstract Crotalid envenomation is a neglected collective health problem involving many countries in America, which need secure and inexpensive snake anti-venom treatments. Here, high antibody titers (IgY) were raised in the Ostrich (Struthio camelus) egg yolk by immunizing with the venom of Venezuelan venomous Crotalus snakes. Ostriches were immunized with a pool of venoms from common rattlesnake (Crotalus durissus cumanensis), Uracoan rattlesnake (Crotalus vegrandis), Guayana rattlesnake (Crotalus durissus ruruima) and black rattlesnake (Crotalus pifanorum). The anti-snake venom antibodies were prepared from egg yolk by the water dilution method, enriched by the addition of caprylic acid (CA) and precipitation with ammonium sulfate at 30% (W/V). The purity and molecular mass of the final product was satisfactory, yielding a single ∼ 175 kDa band in SDS-PAGE gels ran under non-reducing conditions. In the immunoblot analysis, specific binding of the antivenom was observed with most venom proteins. The LD50 was 16.5 g/mouse (825 μg/kg body weight). High titers of IgY against Crot/pool venom were shown by ELISA. The median effective dose (ED50) was 19.66 mg/2LD50. IgY antibodies neutralized efficiently the Crot/pool venom lethality. As far as we know, this is the first anti-snake venom produced in ostriches, which could make this technology an affordable alternative for low-income countries, since it is likely to produce manteniabout 2-4 g of IgY per ostrich egg. Hence, almost 400 g of IgY can be purified from only one ostrich during a year. In addition, there are enormous differences in the cost of investment in the maintenance of horses, from the points of view of infrastructure, feeding and veterinary care, in which the cost can reach USD 100 per animal per day, compared to a maintenance cost of USD 146 per month per producing bird. These results are encouraging and could easily be extrapolated to the manufacturing of other antivenoms and antitoxins as well, as they could be applied to the manufacturing of potential diagnostic tools.

Resumen El envenenamiento por crotálidos es un problema de salud colectiva desatendido, que involucra a muchos países del continente americano, los cuales necesitan tratamientos seguros y económicos. En este trabajo, se obtuvieron títulos altos de anticuerpos (IgY) producidos en yema de huevo de avestruz (Struthio camelus) mediante la inmunización con el veneno de serpientes venezolanas del genero Crotalus. Se inmunizaron avestruces con una colección de veneno de serpientes de cascabel común (Crotalus durissus cumanensis), cascabel de Uracoa (Crotalus vegrandis), cascabel de Guayana (Crotalus durissus ruruima) y cascabel negra (Crotalus pifanorum). Los anticuerpos anti-veneno de serpiente se prepararon a partir de yema de huevo por el método de dilución en agua, enriquecidos mediante la adición de ácido caprílico (CA), seguido de una precipitación con sulfato de amonio al 30% (P/V). La pureza y masa molecular de los anticuerpos (IgY) se definieron mediante ensayos de SDS-PAGE nativos y las masas moleculares se establecieron electroforéticamente, obteniéndose una única banda de IgY de ∼ 175 kDa. El análisis de inmunotransferencia mostró la unión específica del antiveneno con la mayoría de las proteínas del veneno. La DL50 fue de 16,5 μg/ratón (825 μg / kg de peso corporal); Se mostraron títulos altos de IgY contra el veneno de Crot / pool mediante ELISA. La dosis mediana efectiva (DE50) fue de 19,66 mg/2 LD50. Los anticuerpos IgY neutralizaron eficazmente la letalidad del veneno de Crot / pool. Hasta donde sabemos, se trata del primer antídoto de serpiente producido en avestruces, lo que podría abaratar la producción de este tratamiento en países del tercer mundo. Ya que es probable que se obtengan alrededor de 2-4 g de IgY por huevo de avestruz. Por lo tanto, se podrían purificar casi 400 g de IgY de un solo avestruz durante un año. Asimismo, debido a las enormes diferencias en el costo de inversión en el mantenimiento de los caballos desde el punto de vista de infraestructura, alimentación y atención veterinaria, en los que el costo puede llegar a los 100 USD por día, frente a los 146 USD por mes de mantenimiento de la producción de aves. Estos resultados abren un campo terapéutico, para la fabricación de otros antivenenos contra un amplio espectro de toxinas y también como probables herramientas de diagnóstico.

Ultrastructural characterizations of the pecten oculi of the common ostrich (Struthio camelus): New insight to scanning electron microscope-energy dispersive X-ray analysis.

The current observation was designed to give a complete ultrastructural description of the pecten oculi of the common ostrich (Struthio camelus). Moreover, this study represents the first attempt to measurements the elements composition of the pecten oculi using scanning electron microscope-energy dispersive X-ray (SEM-EDX) at three regions (apical, body, and basal). To accomplish this study, eight ostrich were examined grossly and under the electron microscope. The vaned-shaped pecten oculi consisted of three regions (apex, body, and base) with 24-25 plates. The pecten oculi was located postero-anteriorly near to the optic nerve disc that was attached by their bases to the retina forming a slightly elevated basal border joining the bases of all pleats, while the apex was linked in a circular bridge. The pleats are separated from each other by the inter-pleat spaces that are very clear at the base and nearly not observed at the apical part. The outer pleat's surface carried numerous prominences that pointed to the existence of numerous afferent and efferent pecteneal blood capillaries vessels. The vitreopecteneal limiting membrane separated the pecten oculi from the vitreous body. Our findings concluded that, the high number of thick pecteneal pleats was related to the diurnal activity of the common ostrich. SEM-EDX shows that the carbon percentage in the three regions is the highest that representing about half of all elements, while the oxygen percent is about one-third; meanwhile, the lowest percentage is the sulfate at the apical region, and the calcium at the body and basal regions.

The Anti-Inflammatory Effect of a γ-Lactone Isolated from Ostrich Oil of Struthio camelus (Ratite) and Its Formulated Nano-Emulsion in Formalin-Induced Paw Edema.

The ostrich oil of Struthio camelus (Ratite) found uses in folk medicine as an anti-inflammatory in eczema and contact dermatitis. The anti-inflammatory effect of a γ-lactone (5-hexyl-3H-furan-2-one) isolated from ostrich oil and its formulated nano-emulsion in formalin-induced paw edema was investigated in this study. Ostrich oil was saponified using a standard procedure; the aqueous residue was fractionated, purified, and characterized as γ-lactone (5-hexyl-3H-furan-2-one) through the interpretation of IR, NMR, and MS analyses. The γ-lactone was formulated as nano-emulsion using methylcellulose (MC) for oral solubilized form. The γ-lactone methylcellulose nanoparticles (γ-lactone-MC-NPs) were characterized for their size, shape, and encapsulation efficiency with a uniform size of 300 nm and 59.9% drug content. The γ-lactone was applied topically, while the formulated nanoparticles (NPs) were administered orally to rats. A non-steroidal anti-inflammatory drug (diclofenac gel) was used as a reference drug for topical use and ibuprofen suspension for oral administration. Edema was measured using the plethysmograph method. Both γ-lactone and γ-lactone-MC-NPs showed reduction of formalin-induced paw edema in rats and proved to be better than the reference drugs; diclofenac gel and ibuprofen emulsion. Histological examination of the skin tissue revealed increased skin thickness with subepidermal edema and mixed inflammatory cellular infiltration, which were significantly reduced by the γ-lactone compared to the positive control (p-value = 0.00013). Diuretic and toxicity studies of oral γ-lactone-MC-NPs were performed. No diuretic activity was observed. However, lethargy, drowsiness, and refusal to feeding observed may limit its oral administration.

Management of Knuckling in an Ostrich (Struthio camelus) Using a Custom-Made Orthotic Shoe.

A 4-year-old female ostrich (Struthio camelus) developed knuckling on its left foot after a traumatic event. Conservative treatment, rest, and traditional splinting methods failed to resolve the gait abnormality or improve mobility. A dynamic multicomponent orthotic shoe was then custom designed and fabricated with an ultra-high-molecular weight, low-pressure polyethylene polymer (St 1000 DIN16972 TG2) to correct the foot malposition. The affected foot and leg were wrapped with soft padding and the orthosis was attached and secured by nylon belts (Nylon PA [polyamide] 6, a semicrystalline polyamide polymer) with self-locking modified wrench straps. The orthosis immediately prevented knuckling and improved ambulation. After 2 weeks, this shoe was replaced with a modified orthotic shoe of lighter weight to improve kinetics and ease of use by the bird. The modified orthosis dramatically improved ambulation and was left attached to the affected leg for 7 more weeks. Thereafter, the bird was able to ambulate comfortably without the aid of the shoe, even though permanent anatomical changes to the affected leg seemed to restrict its speed of locomotion. The ostrich had another unfortunate traumatic event 10 weeks later, the result of which was knuckling on the contralateral (right) foot. After routine medical and supportive care, the orthosis was then applied to the right foot for a period of 9 weeks. During this period the bird was able to ambulate well, despite having to support the bulk of its weight on the previously affected left limb. At the end of 9 weeks, the orthosis was removed, and the bird was able to ambulate without aid, although the bird's speed of locomotion was considerably reduced. After recovery of its leg problems, the ostrich was confined to a relatively small paddock for the rest of its life.

Self-limiting Orbital Emphysema Following Ocular Evisceration and Demonstration of Nasolacrimal-Oropharyngeal Communication in a South African Ostrich (Struthio camelus australis).

A 25-year-old, male, sanctuary-owned, South African ostrich (Struthio camelus australis) was evaluated for orbital emphysema after evisceration of a nonvisual and chronically irritated eye. On initial ophthalmic examination, the ostrich's left eye displayed severe corneal fibrosis, broad anterior synechia, and a shallow anterior chamber, all suggestive of a previous corneal perforation. Conjunctival hyperemia and eyelid crusts were also present, reportedly associated with chronic rubbing. Evisceration of the left eye was performed by excising the eyelid margins, conjunctiva, nictitans, cornea, and intraocular contents. Four weeks postoperatively, a nonpainful, fluctuant swelling of the surgical site was noted. Trocarization of the surgical site verified orbital emphysema and served to temporarily decompress the orbit. Orbital emphysema reoccurred within 48 hours but gradually regressed without intervention over the subsequent 9 months. A Jones test was performed in the healthy, right eye and demonstrated clear communication to the oropharynx. To our knowledge, this is the first reported case of an evisceration performed on an ostrich and the first reported case of orbital emphysema in any avian species. It is probable that the emphysema noted in this case was secondary to nasolacrimal duct-oropharynx communication.

Meat quality, skin damage and reproductive performance of ostriches exposed to extensive human presence and interactions at an early age.

The effect human presence and interactions performed after hatch to 3 months of age has on ostrich meat quality, skin damage and reproductive performance at a later age was investigated in 416-day-old ostrich chicks. The chicks were allocated to one of the three treatments, which varied with regard to exposure to human presence and care for 3 months post-hatch: HP1-extensive human presence with physical contact (touch, stroking), gentle human voice and visual contact; HP2-extensive human presence with gentle human voice and visual contact without physical contact; S-standard control treatment, where human presence and visual contact were limited to routine management, feed and water supply only. Carcass attributes (carcass weight, dressing percentage and drumstick weight), meat quality traits (pH, colour and tenderness) and skin traits (skin size, skin grading and number of lesions) were evaluated on twenty-four 1-year-old South African Black (SAB) ostriches. Reproductive performance (egg production, average egg weight, number of clutches, clutch size, chick production, average chick weight, fertility and hatchability percentage) were recorded for the first three breeding seasons of 23 SAB pair-bred females from this study. No differences in carcass attributes, meat quality, skin traits and reproductive performance were found between treatments (P > 0.05). It was evident that exposure of day-old ostriches to extensive human presence and interaction as chicks did not influence carcass attributes, meat quality or skin traits at slaughter age, but more importantly, it did not compromise their reproductive performance.

Anatomy of the Tarsometatarsal Region and Digits in the Ostrich (Struthio Camelus): A Computed Tomography and Cross-Sectional Study.

The ostrich is the largest living bird and has unique characteristics in its locomotor system that differentiate it from other bird species. The purpose of this study was to provide a reference atlas of reference-interval computed tomography (CT) and cross-sectional anatomy of the tarsometatarsal region and digits in the ostrich (Struthio camelus). The pelvic limbs of 25 ostriches were used for this imaging study. The transverse CT images were obtained from the middle third of the tarsometatarsal bone to the distal end of the third digit. The specimens were frozen and sectioned with an electric band saw at 1.5-2 cm intervals. The CT images were compared with the corresponding frozen cross sections. The bones, ligaments, and tendons were identified and labeled at each 1.5-2 cm intervals. The CT images provided anatomic details of the tendons and ligaments in the tarsometatarsal region and digits of the ostrich. The transverse CT images provided an excellent depiction of the anatomic structures of the leg and foot when compared with the corresponding frozen cross sections. The information presented in this study may be used as an initial reference when evaluating the CT images of an ostrich's tarsometatarsal region and digits. Moreover, the information provided in this report may be helpful in determining definitive diagnoses of musculoskeletal disorders affecting the lower leg in this species.

Ostrich ejaculate characteristics and male libido around equinox and solstice dates.

The study evaluated the effect of time of the year in which changes in photoperiod occurs on ostrich semen characteristics and male libido. Semen was collected for 5 days before, on and 5 days after winter solstice (21 June 2016), spring equinox (22 September 2016), summer solstice (21 December 2016) and autumn equinox (20 March 2017) in the southern hemisphere. Semen was collected from 10 South African Black ostrich males (average age ± standard deviation; 4.5 ± 2.27 years) using the dummy female. Semen volume, sperm concentration, total sperm per ejaculate, sperm motility traits, percentage of normal sperm, head and tail abnormalities and percentage of affected sperm in the hypo-osmotic swelling test (HOS) were evaluated. Male libido defined as the willingness of males to mount the dummy female was also recorded. Semen samples collected around summer solstice, spring and autumn equinox were higher in sperm concentration and sperm output compared with winter solstice (P < 0.05). Study periods did not influence semen volume, sperm motility traits, the percentage of normal sperm, head abnormalities and HOS. Tail abnormalities were higher around winter solstice than around spring equinox (P < 0.05). Male libido and the success of semen collection were significantly higher around spring equinox (P < 0.05). Changes in photoperiod in the southern hemisphere do not affect semen production in ostriches. However, high sperm output and male libido around spring equinox and summer solstice dates suggest that these periods may be preferred for semen collection for artificial insemination and storage purposes.

Extensive human presence and regular gentle handling improve growth, survival and immune competence in ostrich chicks.

A total of 416 day-old ostrich chicks were randomly allocated to one of the three different husbandry practices for 3 months after hatch; HP1 (extensive human presence with gentle human voice, visual and gentle physical stimuli), HP2 (similar to HP1 but without physical stimuli) and S (human presence limited to supply of feed and water). Chick weight (kg) was measured at 6 and 12 weeks of age, while mortalities were recorded daily to calculate the survival rate. Finally, chicks' antibody responses to vaccination against Newcastle disease (NCD) was measured using the Hemagglutination-Inhibition (HI) test at 20 weeks of age. While HP1 chicks were heavier and survived better to 6 weeks of age than HP2 and S chicks (p < .05), no difference was observed thereafter (p > .05). Furthermore, HP1 chicks had an improved immune competence, as illustrated by their lower percentage of positive HI titers, compared to HP2 and S chicks (p < .05). Hence, integrating extensive human presence with positive human-chick interactions may assist in alleviating challenges related to chick rearing in the ostrich industry.

Major shifts in gut microbiota during development and its relationship to growth in ostriches.

The development of gut microbiota during ontogeny is emerging as an important process influencing physiology, immunity and fitness in vertebrates. However, knowledge of how bacteria colonize the juvenile gut, how this is influenced by changes in the diversity of gut bacteria and to what extent this influences host fitness, particularly in nonmodel organisms, is lacking. Here we used 16S rRNA gene sequencing to describe the successional development of the faecal microbiome in ostriches (Struthio camelus, n = 66, repeatedly sampled) over the first 3 months of life and its relationship to growth. We found a gradual increase in microbial diversity with age that involved multiple colonization and extinction events and a major taxonomic shift in bacteria that coincided with the cessation of yolk absorption. Comparisons with the microbiota of adults (n = 5) revealed that the chicks became more similar in their microbial diversity and composition to adults as they aged. There was a five-fold difference in juvenile growth during development, and growth during the first week of age was strongly positively correlated with the abundance of the genus Bacteroides and negatively correlated with Akkermansia. After the first week, the abundances of six phylogenetically diverse families (Peptococcaceae, S24-7, Verrucomicrobiae, Anaeroplasmataceae, Streptococcaceae, Methanobacteriaceae) were associated with subsequent reductions in chick growth in an age-specific and transient manner. These results have broad implications for our understanding of the development of gut microbiota and its associations with animal growth.

The Effect of Extensive Human Presence at an Early Age on Stress Responses and Reactivity of Juvenile Ostriches towards Humans.

The effect of extensive human presence and regular gentle handling performed at an early age (0⁻3 months old) on stress responses and reactivity of juvenile ostriches towards humans was investigated. A total of 416 ostrich chicks over two years were exposed to one of three treatments for three months after hatching; namely, Human Presence 1 (HP1, N = 144): extensive/prolonged human presence with physical contact (touch, stroking), gentle human voice, and visual stimuli; Human Presence 2 (HP2, N = 136): extensive/prolonged human presence without physical contact, but with gentle human voice and visual stimuli; and the Standard treatment (S, N = 136): human presence limited to routine feed and water supply as a control. At 7.5 months of age, the plasma heterophil/lymphocyte (H/L) ratio was measured before and 72 h after feather harvesting and feather clipping to determine acute stress responses, while chronic stress was measured by quantification of corticosterone (CORT) concentrations in the floss feathers of the birds. Birds' behavioural response towards a familiar or an unfamiliar handler was evaluated at 12 months using docility and fear tests, and through behavioural observations conducted on random days between the ages of 8⁻13 months. Willingness to approach, and to allow touch interactions, aggressiveness, and exhibition of sexual display towards the handler, was recorded. No difference in the H/L ratios before and after feather harvesting and clipping was observed in HP1 birds, whereas H/L ratios showed a significant increase 72 h post feather harvesting and clipping in HP2 and S birds (p < 0.05). Birds from the S treatment exhibited a significantly (p < 0.05) higher feather CORT concentration compared with HP1 birds, while HP2 birds had intermediate responses. Birds' reactivity towards humans and temperament as evaluated using behavioural observations, docility, and fear tests was not affected by treatment (p > 0.05). However, HP1 and HP2 birds were more inclined (p < 0.05) to approach a familiar rather than an unfamiliar handler during the behavioural observations, indicating an ability to distinguish between a familiar and an unfamiliar handler. Overall, the results indicate that early gentle human interactions with ostrich chicks can be beneficial in reducing physiological stress sensitivity later in life and facilitate the ability of ostriches to distinguish between familiar and unfamiliar handlers.

Mineral profiling of ostrich (Struthio camelus) seminal plasma and its relationship with semen traits and collection day.

Successful assisted reproduction techniques, with specific focus on in vitro semen storage for artificial insemination, are dependent on certain key elements which includes the biochemical profiling of semen. The objective of this study was to complete an ostrich seminal plasma (SP) evaluation by inductively coupled plasma mass spectrometry (ICP-MS) among seven males at different daily intervals (day 1, 3, 7, 11, 15, 19, 21, 23, 25, 26, 27, 28) for a period of 28 days during spring (August to September) for mineral profiling. The effect of collection day and male on sperm concentration, semen volume and seminal plasma volume, was explored as well as the relationships amongst these specific sperm traits and SP minerals. Variation amongst SP mineral concentrations, accounted for by the fixed effects of sperm concentration, semen volume, seminal plasma volume, collection day and male, ranged from 18% to 77%. Male had the largest effect on variation in SP minerals, namely: phosphorus (P), potassium (K), calcium (Ca), sodium (Na), boron (B), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), barium (Ba), arsenic (As) and selenium (Se). Sperm concentration instigated fluctuations of P, magnesium (Mg), B, zinc (Zn), Fe, aluminium (Al), Se, manganese (Mn) and lead (Pb). Semen volume had an effect on Na, K, B, Pb and Ba while seminal plasma volume only influenced variation in Na. There were fluctuations among collection days of specific micro minerals, Ni and Mo, with initial Ni concentrations being relatively greater and Mo at lesser concentrations. Semen volume, seminal plasma volume and sperm concentration varied amongst males. Sperm concentrations during the initial collection days, 1 and 3, were less than that for days 7 to 28. Significant variation of SP minerals and sperm characteristics among ejaculates and males suggest an association of these specific elements with sperm function and are, therefore, considered to be of potential importance to success of assisted reproduction technology for the ostrich. The relationship amongst sperm concentration and collection day confirms the need to conduct an initial period of collection to stabilise a greater sperm concentration to optimise sperm numbers for artificial insemination purposes.

Ostrich specific semen diluent and sperm motility characteristics during in vitro storage.

The dilution of semen is a very important initial process for semen processing and evaluation, storage and preservation in vitro and efficient artificial insemination. The aim of the study was to evaluate the effect of two synthetic diluents (OS1 and OS2) on ostrich sperm motility parameters during in vitro storage. Formulation of OS1 was based on macro minerals (Na, K, P, Ca, Mg) and OS2 on the further addition of micro minerals (Se and Zn), based on mineral concentration determined in the ostrich seminal plasma (SP). Sperm motility was evaluated at different processing stages (neat, after dilution, during storage and after storage) by measuring several sperm motility variables using the Sperm Class Analyzer® (SCA). Processing (dilution, cooling and storage) of semen for in vitro storage purposes decreased the values for all sperm motility variables measured. The percentage motile (MOT) and progressive motile (PMOT) sperm decreased 20% to 30% during 24 h of storage, independent of diluent type. Quality of sperm swim (LIN, STR and WOB), however, was sustained during the longer storage periods (48 h) with the OS2 diluent modified with Se and Zn additions. Quality of sperm swim with use of OS1 was 6% to 8% less for the LIN, STR, and WOB variables. Male fitted as a fixed effect accounted for >60% of the variation for certain sperm motility variables (PMOT, MOT, VCL, VSL, VAP and ALH) evaluated at different processing stages. Semen from specific males had sustained sperm motility characteristics to a greater extent than that of other males during the 24-h storage period.