Ultrasonographic findings of pathological changes in the mammary gland in Bulgarian native goats

The Role of Ewes’ Udder Health on Echotexture and Blood Flow Changes during the Dry and Lactation Periods

Simple Summary

During lactation, the mammary glands of ewes are prone to infections caused by numerous pathogens. Consequently, mastitis and other udder abnormalities frequently occur. Unfortunately, udder inflammation, whether clinical or subclinical, it poses a significant barrier to livestock profitability by reducing milk production, decreasing milk quality, and suppressing ewes’ reproductive performance. The cost of subclinical mastitis often is greater than that of clinical mastitis. Thus, such conditions must be treated during the dry period, which is important for mammary gland repair and recovery. Moreover, an early diagnosis is crucial for effective treatment. Ultrasonography is a useful tool that is employed in the detection of echotextural and hemodynamic changes. During recent decades, there has been an increasing scientific interest in the contributions of B-mode and Doppler to the determination of physiological and pathological conditions occurring in mammary glands, which cannot be detected during a physical examination. Therefore, the aim of the present study was to investigate the alterations in ewes’ udders’ echotexture and blood flow during the end of lactation, the stages of dry period, and the first days of the postpartum period. A further objective was to investigate the hemodynamic and echotextural differentiations between ewes having healthy udders and ewes having subclinical mastitis.

Abstract

The objective of the current study was to investigate the echotextural and hemodynamic changes of ewes entering the dry period with or without subclinical mastitis. B-mode and color Doppler ultrasonography were applied to 12 Chios ewes (6 with healthy udders (group A) and 6 with subclinical mastitis (group B)) before the dry period, during the dry period (the involution phase, steady state, and transition phase), and postpartum. The color Doppler of the mammary arteries was used to evaluate them according to the pulsatility index (PI), resistive index (RI), end-diastolic velocity (EDV), time-averaged maximum velocity (TAMV), blood flow volume (BFV), and artery diameter (D). Udder parenchyma images, analyzed by Echovet v2.0, were used to evaluate the mean value (MV), standard deviation (SD), gradient mean value (GMV), gradient variance (GV), contrast (Con), entropy (Ent), gray value distribution (GVD), run length distribution (RunLD), and long run emphasis (LRunEm). In the involution phase, the PI was higher in group B compared to group A (p ≤ 0.05). The PI and RI were higher postpartum, whereas the EDV, TAVM, and D were higher in the transition phase (p ≤ 0.05). Neither the period nor the ewe group affected the MV, SD, GMV, GV, Con, and GVD values (p ≤ 0.05). In the steady state, the LRunEm was higher in group B, but postpartum, it was higher in group A (p ≤ 0.05). In conclusion, B-mode and Doppler can reveal differences (i) between healthy ewes and ewes with subclinical mastitis and (ii) among the different periods studied. Further research is needed on the blood flow and echotexture indices of the udders of ewes with unilateral subclinical mastitis.

Achados ultrassonográficos da glândula mamária de cabras naturalmente infectadas com o vírus da artrite encefalite caprina

RESUMO A artrite encefalite caprina é uma virose que está distribuída mundialmente nos rebanhos. Na forma mamária, é predominante a mastite crônica, que pode causar assimetria e endurecimento do úbere, mais conhecida como mastite endurativa crônica, levando à redução na produção leiteira. A ultrassonografia é um bom método de avaliação da glândula mamária, pois consiste em uma técnica não invasiva, rápida e de fácil aplicação. Este estudo objetivou avaliar as características ultrassonográficas (escala de cinza, ecogenicidade e homogeneidade) do parênquima mamário de 20 cabras sororreagentes e 20 não sororreagentes para o vírus da artrite encefalite caprina. Observou-se que o diâmetro médio dos linfonodos retromamários de animais sororreagentes (0,72cm) para o vírus da artrite encefalite caprina foi menor (P=0,02) que o dos animais não sororreagentes (0,93cm). Na análise entre as porções do úbere, os valores da escala de cinza do terço distal da porção caudal do parênquima mamário foram maiores nos animais sororreagentes (P<0.0001, lado direito; P=0,02, lado esquerdo). Tais dados sugerem que o aumento na escala de cinza do parênquima mamário das cabras pode estar correlacionado com as alterações crônicas causadas pela artrite encefalite caprina, como a mastite endurativa. Em relação aos aspectos subjetivos de ecogenicidade e homogeneidade, os grupos não apresentaram diferença entre si (P>0,05), exibindo em sua maioria padrões hipoecoicos e heterogêneos. Diante dos resultados, o presente estudo aponta indícios de que a artrite encefalite caprina pode causar alterações na escala de cinza mensuráveis pela ultrassonografia, a qual pode ser utilizada como método auxiliar eficiente e não invasivo no monitoramento e diagnóstico precoce da mastite endurativa.

B-mode and Doppler sonography of the mammary glands in dairy goats for mastitis diagnosis

This study aimed to evaluate the sonographic characteristics of the udder and teats and to determine the Doppler indexes of mammary artery in healthy and undergoing subclinical and clinical mastitis goats. Thirty animals among Saanen and Alpine Brown goats were arranged in three groups, healthy goats (HG), goats with subclinical mastitis (SMG) and goats with clinical mastitis (CMG). Using the B-mode, the sonographic characteristics (echotexture and echogenicity) and biometry (diameter and area of the udder cistern, diameter and area of the teat cistern and thickness of the teat wall) were evaluated. Using Doppler ultrasonography, the vascular indexes of the mammary artery were obtained. It was observed hyperechogenicity with solid component in the gland cistern when comparing animals with clinical mastitis and healthy mammary tissue. Regarding the echotexture of the breast tissue, there was heterogeneity in the mammary parenchyma on the three groups, for the milk, it was observed homogeneity for animals on HG and SMG and heterogeneity for animals on CMG. Grey-scale quantitative assessment revealed increase in echogenicity (mean value) for all the structures when comparing the three groups. Biometry did not reveal statistical difference between groups, for none of the evaluated structures. Doppler examination of the mammary artery showed the decrease of end diastolic velocity and raise of pulsatility index between groups. The association of B-mode and Doppler ultrasonography is useful for the evaluation of the udder of dairy goats with mastitis. It is a sensitive and specific method for the study of this disease. Doppler mode was unable to establish reliable criteria for diagnosis of subclinical mastitis. Moreover, the quantification of echogenicity is a useful technique for the evaluation of the milk in animals with mastitis; therefore, it is suggested that it can be used as complementary technique for the diagnosis of mastitis in goats.