Multivariate Analysis of Udder morphometric Traits Associated with Mastitis Incidence in Dairy Cattle

Introduction

The dairy sector plays a vital role in strengthening the rural economy and serves as a major source of livelihood for crores of people across the globe. In India, livestock rearing and milk production have been an integral part of the culture for thousands of years, shaping the unique structure of the country's dairy industry. Unlike many developed nations, India's dairy sector is driven largely by small and marginal farmers. It is often described as a system of "production by the masses" rather than "mass production," as most dairy farmers own only one to three animals. The sustained efforts of these smallholders, along with their livestock, have enabled India to emerge as the largest milk-producing country in the world. At present, the dairy sector provides employment to more than eight crore families in India. Its distinct strengths lie in the active participation of small farmers, the cooperative framework, and the contribution of indigenous cattle breeds, all of which together form the backbone of the sector. Milk production in India is growing at a rate exceeding 6 percent annually, compared to about 2 percent globally, and the per capita availability of milk in the country is also considerably higher than the world average. Mastitis, derived from the Greek words mastos meaning breast and itis meaning inflammation, is a complex, multi-etiological disease defined as inflammation of the parenchyma of the mammary gland. It is characterized by physical, chemical, and usually bacteriological changes in milk, along with pathological alterations in glandular tissues. The incidence of mastitis is influenced by a range of animal, environmental, managemental, and nutritional factors. In the present work, emphasis has been placed on animal-related factors, particularly udder morphology and biometry, including udder width, height, and length, in relation to mastitis occurrence. Differences between cows and buffaloes, as well as between indigenous and crossbred cows, were examined, as udder shape and morphological traits play a significant role in predisposing animals to mastitis. Patel (2014) reported that the incidence of mastitis was highest in cows with goaty udders (80.00%), followed by pendulous (60.61%), trough (46.02%), and round-shaped udders (35.90%). With respect to udder measurements, he observed that the highest proportion of mastitis-positive cases occurred in cows having medium udder length (48-68 cm; 49.32%), smaller udder width (<55 cm; 51.52%), and greater udder depth (>28 cm; 64.00%). Bharti et al. (2015) observed significantly higher mean somatic cell counts (SCC) in cows with pendulous udders (6.393±0.037) compared to those with normally shaped udders (5.120±0.034). They further noted that mean SCC values were highest in flat teats (6.189±0.105), followed by inverted (5.850±0.068) and pointed teats (5.030±0.035). Modh et al. (2017) [7] , in a study conducted on Gir cows, reported mastitis incidence rates of 47.05% in trough-shaped udders, 51.51% in round, 63.15% in goaty, and 55.55% in pendulous udders. Ahmad (2011) [5] studied the various shapes of udders and incidence of mastitis and reported that, trough shape of udder was most prevalent (56.80%), followed by round (28.5%), pendulous (12.62%), and goaty udders (2.0%). Further, the incidence of mastitis was higher in pendulous shaped (53.13%), followed by goaty (30%), round (28.97%) and trough shaped udders (19.10%). Regarding udder width, higher incidence (53.03%) of mastitis was found in the udder with udder width >73 cm as compared to udder width < 56 cm. (18.39%). With respect to the udder depth, higher incidence (41.18%) of mastitis was found in the udders with udder depth of <53 cm and lower (21.31%) in the udders with udder depth >65 cm. Sinha et al. (2022) [9] studied the udder and teat morphometric traits with the occurrence of mastitis in Karan Fries and Sahiwal cattle. The rear udder height, rear udder width, udder width and fore udder attachment were found to be the important udder morphometric traits associated with the occurrence of mastitis

Studies done previously

Materials and methods Location of the study and Research design

The study was conducted in the Mancherial, Siddipet, and Rangareddy districts of Telangana State, representing the North, Central, and South agro-climatic zones, respectively. From each district, four mandals were selected, and three villages were chosen from each mandal for the study. A list of dairy farmers for whom dairying served as a major or subsidiary source of income was obtained from local milk cooperative societies and personnel of the Animal Husbandry Department. From each selected village, eight dairy farmers were randomly selected, resulting in a total sample size of 288 respondents. Data were collected through personal visits using a prestructured and pre-tested interview schedule. A survey was undertaken to assess udder morphology, including udder biometry parameters such as length, width, and depth, along with their characteristics, and to study the incidence of mastitis based on the distribution of different udder shapes and their association with mastitis occurrence. A semistructured questionnaire, common to all respondents, was designed to capture information related to dairy cattle management practices. The enrolled farmers, who owned dairy cows and buffaloes, were evaluated for mastitis incidence using recommended diagnostic tests. The study adopted an exploratory research design with a simple random sampling technique. Rapport was maintained with the farmers throughout the investigation to ensure accurate responses, and data were collected through informal and friendly interactions at their homes and farms during the early and late hours of the day. The collected data were analyzed using appropriate standard statistical procedures to draw meaningful conclusions.

Udder morphology with their characteristics Udder shape

Shape of udder were determined through visual appraisal method adopted by Cerkascenko (1958), accordingly categorized into different types, viz., trough, round, goaty and pendulous.

Biometry of udder (length, width and depth)

Udder length, width and depth were measured one to two hours before evening milking after securing the animals properly in a standing position on a leveled floor for the accuracy. All the measurements were recorded in centimeters.

Udder length: The udder length was measured from the rear attachment of the udder, near the escutcheon, to the front of the udder where it blends smoothly with the body Udder width: The udder width was measured as a distance between two lateral lines of attachment of the udder to abdominal wall, beneath the flank.

The measuring tape was kept in position on one side of the animal, under flank, near the stifle joint and it was passed over in between fore and rear teats to the other side. Large (more than 67) Large (more than 96) Large (more than 20)

Results and discussion Distribution of different udder shapes and incidence of mastitis

The data on percent distribution of different udder shapes are presented in Table 5.1 and Fig. 1. The results of the table read that, the trough-shaped udder was the most frequent (34.73%), followed by round (31.94%), pendulous (18.75%) and goaty (14.58%). Further, slightly higher degree of pendulous udder shape was observed in dairy cattle which might be due to the increasing age and parity that weaken the median suspensory ligament of the udder.

Udder shape and incidence mastitis

Udder shape Frequency (N) Percentage (%) The results of the table 4.15 shows that, the percent incidence of mastitis was 40.22%, 35%, 57.41% and 31% among round, trough, pendulous and goaty shape of udders respectively.

Further the table also revealed that the shape of udder had only 40.0 percent influence on incidence of mastitis.

Udder morphological risk factors associated with the incidence of mastitis in dairy cattle

Observation of Table 4.16, indicate that, the incidence of mastitis was 27.7, 36.4 and 51.3 percent in dairy animals with small (less than 57cm), medium (57-68cm) and large (more than 68cm) udder length, respectively. As the length of udder increased above 57cm (medium and large) the incidence of mastitis was recorded significantly higher (P<0.05). Similarly, a higher incidence of mastitis was observed in udder width greater than 67cm (49.1%) as compared to udder width medium (41%) and smaller than 54cm (26.7%).

With respect to the circumference of the udder, higher incidence (50%) of mastitis was found in the animals with udder circumference more than 96 cm as compared to animals having medium (44.2%) and less than 80 cm udder circumference (30.6%). Similarly, with respect to the udder depth, higher incidence (51%) of mastitis was found in the animals with larger udder depth (more than 20 cm) compared to medium (38.1%) and lower udder depth (30.6%). The chi-square analysis of udder morphological risk factors associated with mastitis in dairy cattle revealed that, there was significant effect in relation to udder length, width, udder circumference and udder depth (Table 4.16). The width of udder showed a significant(P<0.05) effect on the incidence of mastitis.

References

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