Desenvolvimento da glândula mamária de bezerras mestiças aleitadas com diferentes concentrações de sólidos na dieta líquida

• Ano de defesa: 2016
• Autor(a) principal: Pamela Micheli Furini
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Área de parênquima; Desenvolvimento; Escore de palpação; Dieta em veterinaria; Bezerro Alimentação e rações; Glândulas mamárias
• Link de acesso: http://hdl.handle.net/1843/BUOS-BC6NAA

The aim of this study was to determine the effect of increasing total solids (TS) in liquid diet during preweaning phase on mammary gland development in dairy heifers. The increase in total solids (TS) was obtained with the addition of milk replacer powder to whole milk. Crossbreed Holstein-Gyr heifers (n = 60) were distributed in four treatments with different TS concentrations: 13.5% (n = 15); 16.1% (n = 15); 18.2% (n = 15) and 20.4% (n = 15). The liquid diets were provided from 5 to 55 d of age. From 56 to 59 d of age, the total amount of liquid feed was reduced by half, maintaining only morning feedings. Heifers were weaned at 60 d and monitored until 90 d of age. From 60 to 90 days old, the same concentrate of the preweaning period was supplied. Corn silage was added to the diet at 70 days of age. Ultrasound mammary gland evaluations were performed weekly between the wk 5 to 11 of age, using a B-mode ultrasound equipped with micro-convex transducer of 6 MHz frequency. The images were obtained from the front and rear quarters with the animal laid on lateral decubitus, with the probe in a standardized position with a 45º inclination in relation to the teat position, always in caudal-cranial direction. The images obtained were saved in BMP format and then transferred to the ImageJ® program for analysis. In those same weeks, the manual palpation of mammary parenchyma was performed. Increased TS concentration of liquid diet during the preweaning period increased BW of heifers, but did not alter mammary parenchyma growth and the deposition of adipose tissue in the mammary gland evaluated by ultrasonography. The oval-shaped structure of mammary parenchyma was altered after two months of age. In the evaluated period, mammary parenchyma growth was isometric with respect to the body growth rate. Palpation scoring of mammary parenchyma had a strong correlation with the ultrasound evaluation of the mammary parenchyma