Reproductive characteristics of captive greater rhea (Rhea americana) males reared in the state of São Paulo, Brazil

Abstract

Rheas (Rhea americana) belongs to the ratite group. Considering the commercial significance of this birds, some techniques, such as semen collection, were standardized. In this study, 107 male rheas (3 to 4 years of age) reared in commercial farms in the state of São Paulo, Brazil, were used. Semen was collected during the breeding and offbreeding seasons of 2001, 2002, and 2003. Bird hierarchical behavior was observed. Birds were restrained performed using a box and a black hood. Semen was collected by digital pressure on the base of the phallus, which size was measured, and the presence or absence of spiral shape was observed. Immediately after collection, semen samples were evaluated for volume, motility, sperm concentration, and morphology. In a limited number of birds, blood samples were collected to measure testosterone levels. Among the 69 birds studied during the breeding season, 44 presented large phalluses, out of which 26 showed spiral shape. The method of semen collection was efficient. The following semen parameter results were obtained: volume (0.68 ±0.14 ml), motility (61.11±11.54%), sperm concentration (3.29±1.33 x10 9 sptz/ml), and number of spermatozoa per ejaculate (2.40±1.38x10 9 sptz/ml). Morphological abnormalities were analyzed and recorded. Testosterone levels were statistically different (p = 0.0161) between the breeding and non-breeding season (53.28±18.41 ng/ml and 5:57±3.81 ng/ml, respectively). Variations in phallus size were also found between the breeding and non-breeding seasons. Larger phalluses and higher testosterone levels were correlated with dominant behavior. The results of the present experiment confirmed that it is possible to collect semen from rheas, allowing the future use of biotechnologies such as artificial insemination.

Head-base bending and disjointed spermatozoa in the emu (Dromaius novaehollandiae): A morphological comparison of two closely related defects

“…Reporting on the incidence of abnormal sperm in the emu, Malecki et al [24] provide a category for "bent sperm" without defining the term whereas Góes et al [25] simply report that bent heads, folded tails and strongly folded tails are observed in the rhea. Midpiece reflexes have been described in the ostrich [26,27] and Soley et al [28] reported an association between cytoplasmic droplets and bent tails in the same species.…”

Effect of temperature, air humidity, and rainfall on the reproductive season of Rhea americana (Linaeus, 1758) at latitude 25°S

“…The breeding season of Rhea americana is in the spring (Immelmann, 1971) and summer, starting in the first warm days of late winter and finishing mid-February (Góes et al, 2010) at 30 • S. In the present study, the animals started the reproductive season in July and stopped in December. This might be because the animals were closer to the equator (25 • S).…”

“…Although the farm breeding of Rhea americana began around 1800, studies of its reproductive behavior have been rare (De Almeida, 2003), mainly comparing it to other species of ratites (flightless birds), such as the ostrich (Góes et al, 2010). Rhea americana initiates reproductive activity as the photoperiod increases, varying according to the latitude (Cubas et al, 2006).…”

“…The females start laying about 25 days after copulation. The male sets the nest, incubates 20-30 eggs in the nest (Bruning, 1971;Góes, Cavalcante, Nichi, Perez, & Barnabe, 2010), establishes a territory (Cubas et al, 2014), and maintains a clean area of 2-3 m 2 , where some females lay their eggs. In nature, incubation time starts five to eight days after the females start laying, and lasts for 20 to 30 days.…”

Morphology and Histochemistry of Juvenile Male American Alligator (Alligator mississippiensis) Phallus

“…In addition to ontogenetic phallus development, androgen mediated regulation of phallus size may be seasonally dynamic. In Rhea americana , phallus size positively correlated with circulating testosterone levels between breeding and non‐breeding seasons (Goes et al,2010). Therefore, the phallic morphologies presented in this manuscript are of a developing juvenile anatomy which will greatly enlarge and elaborate with increased exposure to sex hormones and sexual maturity.…”