Teat morphology across five buffalo breeds: a multi-country collaborative study

Abstract

The buffalo (Bubalus bubalis) is a species of worldwide importance, raised to produce milk, meat, and hides, and often used as a working animal in rural contexts with low access to hi-tech solutions. In the present study, 100 lactating buffaloes (50 primiparous and 50 pluriparous) of five popular breeds were recruited to characterize and compare teat morphology. In particular, the focus was put on the Nili Ravi, Mediterranean, Egyptian, Bulgarian Murrah, and Azeri buffaloes raised in Pakistan, Italy, Egypt, Bulgaria, and Iran, respectively. In all countries, a longitudinal cross-section ultrasound was obtained before the milking to measure teat parameters at individual level: overall, teat canal length (TCL) averaged 24.13 mm, teat diameter (TD) 30.46 mm, cisternal diameter (CD) 17.80 mm, and teat wall (TW) 7.12 mm. The most variable trait across breeds was TCL which was positively correlated with CD and TD and negatively with TW, regardless of the teat position (front/rear or left/right). A strong negative correlation was found between TW and CD (- 0.43). The analysis of variance revealed that the fixed effect of breed significantly affected all the traits except TD. In fact, Bulgarian Murrah, Azeri, and Egyptian buffaloes presented the greatest estimate of TCL, whereas NR the smallest (14.70 mm). The TW was maximum in Nili Ravi, Egyptian, and Mediterranean buffaloes, with estimates equal to 8.19, 7.59, and 8.74 mm, respectively. Nili Ravi also showed the greatest TL (82.39 mm). In terms of CD, the lowest least square mean was that of Mediterranean buffaloes (12.14 mm). Primiparous and pluriparous buffaloes differed in terms of TD, TW, and TL, with older animals presenting the highest least square mean. In terms of position, instead, significant differences were observed for TD, CD, and TL when comparing front and rear teats, as left and right teats did not differ. Teat anatomy includes a set of heritable morphological features and is therefore breed-dependent. Differences presented in this study could be attributed to the divergent breeding objective and selective pressure across the five breeds; e.g., in some cases such as Mediterranean buffalo, selection for decades was oriented to improve milk production and milkability and achieve optimal conformation for mechanical milking. A better understanding of the mammary gland anatomical descriptors can be informative of the history of a breed and could provide useful insights to guide possible selection.

Keywords: Dairy buffalo; Genetic diversity; Mammary gland morphology; Teat anatomy.