Seasonal Morphometric and Stereological Changes in the Testes of Cattle Egret (Bubulcus Ibis)

Abstract

Cattle egrets are important stocky heron seasonal breeder involved in bio-control of ticks and lice in cattle. Despite research documented on morphometric parameters of avian testes including cattle egret there is need for documentation of data on the seasonal changes in the male organ of this species to further buttress the existing literature. The study was undertaken to document the seasonal changes in morphometry, gonadosomatic index and stereology of male sex organ in cattle egret. The mean ± standard error of mean of the weight, length and width of the reproductive organs were compared within and between seasons with student t test using GraphPad prism version 8. The Mean ± SEM weight of the whole testes (1.47 ± 0.10g breeding and 0.68 ± 0.11g non-breeding) was statistically significant (p ≤ 0.05), whole testis gonado-somatic index (0.42 ± 0.03 breeding and 0.25 ± 0.13 non-breeding season) was statistically significant (p ≤ 0.05), left and right testis (0.72 ± 0.06g, 0.76 ± 0.04g breeding and 0.37 ± 0.06g, 0.31 ± 0.05g non-breeding season) not statistically significant within each season (p ≥ 0.05). Testis left and right length (4.33 ± 0.14mm, 4.64 ± 0.14 breeding and 2.80 ± 0.13mm, 3.49 ± 0.16mm non-breeding season) not statistically significant within each season (p  ≥ 0.05) but statistically significant (p  ≤ 0.05) between breeding and non-breeding season, testis left and right width (4.78 ± 0.30mm, 5.12 ± 0.32mm breeding and 2.46 ± 0.29mm, 2.20 ± 0.15mm non-breeding season) were statistically significant (p  ≤ 0.05) between breeding and non-breeding season and left and right vas deferens length (45.44 ± 0.90mm, 46.00 ± 0.96mm breeding and 35.13 ± 0.98mm, 36.28 ± 1.36mm non-breeding season) obtained were significantly increased during the breeding season compared to the non-breeding season (p ≤ 0.05). In conclusion, the result indicated heavier, wider and longer male sex organ, larger germ cell volume and germ cell number in the breeding season than non=breeding season. The study also revealed that the right testis has higher germ cell volume than the left testis in both seasons.  Hence, these findings provide baseline quantitative morphometric data on seasonal reproductive dynamics in the cattle egret, with potential applications in comparative anatomy, reproductive biology and species management.