Desenvolvimento de novilhas leiteiras submetidas a diferentes relações proteína metabolizável: energia metabolizável na dieta

• Autor(a) principal: Albino, Ronan Lopes
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5795
• topic: Glândula mamária; Balanço de nitrogênio; Desempenho; Mammary Gland; Nitrogen balance; Performance; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

This work was conducted to evaluate the mammary gland development and the body growth of Holstein heifers fed to a fast growth under different metabolizable protein and metabolizable energy ratios (MPMER). Twenty five Holstein heifers (weighing 213 ± 67 Kg) were assigned to one of five treatments. The treatments were composed of metabolizable protein and metabolizable energy ratios (MPMER), with 33, 38, 43, 48, 53 grams of metabolizable protein per Mcal of metabolizable energy (ME) to each treatment. All diets were isoenergetic (2.6 Mcal of ME/ Kg DM). The experimental design was randomized blocks, being the weigh at beginning used as factor to local control. The MPMER obtained on the experiment were 36.2, 40.2, 46.2, 47.1 and 50.8 g PM per Mcal of ME. The intakes of CP, EE and NSC were affected (P < 0.05) by treatments. However, there were not (P > 0.05) differences to DMI and NDFI in Kg/day and g/ Kg of body weight (BW). In relation to the digestibility analyses, only CP was affected (P < 0.05) by treatment. There was a reduction (P < 0.05) of the nitrogen microbial and nitrogen intake ratio (Nmic: N-int) and an increase (P < 0.05) of daily excretions of total nitrogen (urinary-N) and of urinary urea nitrogen (UU-N). The MPMER did not affect (P > 0.05) weight gain, hip width, body length, and heart girth. However, the variables wither height and hip height shown a quadratic effect (P < 0.05). Regarding the hormonal and mammary gland evaluations, just the content of IGF-1 on the serum was affected by treatments. Overall, the increase of MPMER led to greater loss of urinary nitrogen. The weight gain was not affected by MPMER, but the gains of wither height and hip height, showed a quadratic response. The brightness of mammary gland images, shown here through of mean of pixels, was not influenced by MPMER in diet of heifers submitted to fast growth.