Anatomy and Physiology of Water Buffalo Mammary Glands: An Anatomofunctional Comparison with Dairy Cattle

Abstract

The present review aims to analyze the anatomical and physiological characteristics of the mammary gland and udders of water buffalo by making an anatomofunctional comparison with dairy cattle. It will also discuss the knowledge generated around the physiological regulation of milk ejection in the water buffalo. It was found that buffalo's average udder depth and width is approximately 20 cm smaller than Bos cattle. One of the main differences with dairy cattle is a longer teat canal length (around 8.25-11.56 cm), which highly influences buffalo milking. In this sense, a narrower teat canal (2.71 ± 0.10 cm) and thicker sphincter muscle are associated with needing higher vacuum levels when using machine milking in buffalo. Moreover, the predominant alveolar fraction of water buffalo storing 90-95% of the entire milk production is another element that can be related to the lower milk yields in buffalo (when compared to Bos cattle) and the requirements for prolonged prestimulation in this species. Considering the anatomical characteristics of water buffalo's udder could help improve bubaline dairy systems.

Keywords: Bubalus bubalis; prestimulation; udder morphology.

Figure 1

Morphologic comparison of the udder of dairy cattle and dairy buffalo. The main difference is the greater development of the udder in cattle resulting in higher milk yields.

Figure 2

Examples of different udder and teat shapes in water buffalo. Shapes of the udder and nipples, respectively, have been described as (A), divided and conical; (B), pendulous and cylindrical; (C), goat shaped and bottle shaped; (D), pear shaped and pear shaped.

Figure 3

Internal structure of the mammary gland of water buffalo. Values written in red are the comparison with Holstein cattle measurements.

Figure 4

Neuroendocrinology of milk ejection. Milk ejection occurs as a response to sensorial stimulus in the mammary gland. These stimuli are transmitted through the inguinal and genitofemoral nerves to reach the dorsal root ganglion (DRG) of the spinal cord. The signaling travels through the spinothalamic tract to connect with the hypothalamus, specifically to the supraoptic nucleus (SON) and paraventricular nucleus, where oxytocin (OXT) is synthesized. Using the hypothalamic–pituitary tract, the neurons in the pituitary gland release OXT to the systemic circulation. Blood vessels in the mammary gland transport OXT to the myoepithelial cells, causing its contraction and the consequent release of milk. MPOA = medial preoptic area.

Figure 5

Comparative anatomy of the mammary glands in lactating cows and buffalo: (A): the sagittal section of the glandular mammary of the adult lactating cow; (B): the sagittal section of the glandular mammary of the adult lactating buffalo; and (C): the sagittal section of the teat of the adult lactating buffalo.

Figure 6

Surface thermal response of the udder of Murrah buffalo before, during, and after suckling. (A) Before suckling, the maximum temperature of the udder and the teat is 37.8 °C and 37.1 °C, respectively. (B) During colostrum intake by the calf, the maximum temperature of the udder and the teat reaches 39.3 °C and 38.4 °C, increasing an average of up to 1.5 °C when compared to the previous thermal image. (C) After suckling, a decrease in the maximum temperature of the udder (38.6 °C) is observed when compared to the B image. However, in comparison to A, both temperatures stay above basal temperature by up to 1.4 °C. Red triangle: maximum temperature; blue triangle: minimum temperature. Radiometric images were obtained using a T1020 FLIR thermal camera. Image resolution: 1024 × 768; up to 3.1 MP with UltraMax. FLIR Systems, Inc. Wilsonville, OR, USA.

Figure 7

Positive and negative stimulus that influence milk synthesis and ejection. CRH: Corticotropin-releasing hormone; ACTH: adrenocorticotropic hormone; SON: supraoptic nucleus; OXT: oxytocin.