Abstract The objective of this study was to evaluate the production, fat and fatty acids of milk as well as the diameter, classification and quantity of the milk fat globules (MFG) of goats consuming a diet with 15% of crude glycerin. Twelve multiparous Saanen goats weighing 40 ± 6 kg and 90 ± 5 days of lactation were used. The experimental design was completely randomized with two treatments (0 and 15% inclusion of glycerin). In this way, each milk sample is classified according to the percentage of milk fat globules that were included in these three size categories. For the variables milk production, fat, diameter, medium and large fat globules and amount of globules showed a significant effect of the inclusion of glycerin in the diet (p < 0.05). Fifteen fatty acids were found, mostly saturated. For caprylic, palmitic, and linoleic fatty acids, there was no significant influence of the inclusion of glycerin (p > 0.05). Can recommend the use of 15% double-distilled glycerin in the feeding of lactating goats increased milk production, the amount of fat, increased the size of the milk fat globule. Regarding the saturated and polyunsaturated fatty acids, they kept the level of 15% of glycerin.

Abstract The objective of this study was to evaluate the effects of replacing corn with bidistilled glycerin from the biodiesel industry on the physicochemical, microbiological, and sensory quality of milk and goat cheese. Twelve Saanen multiparous goats weighing 40 ± 6 kg and 30 ± 5 days of lactation were used. The physicochemical parameters analyzed were: fat (%), non-fat solids (%), protein (%), lactose (%), salts (%), relative density at 15/15 °C (gmL-1), index cryoscopic (°C), electrical conductivity (mScm-1), pH and acidity. The milk from each treatment was used to make the rennet cheese. The physicochemical variables: pH, lipids, ESD, and cheese yield had a significant effect (P < 0.05) for the increasing use of bidistilled glycerin in the goat feeding. The pH, acidity, EST, ESD, and yield variables presented linear regressive effect and lipids quadratic regressive effect. The softness sensory attribute had a significant effect (P < 0.05) for the increasing levels of bidistilled glycerin in the goat diet; the softness decreased as the glycerin level increased. Bi-distilled glycerin, when inserted in the diets of dairy goats at increasing levels, promotes a reduction in the lipid content of milk, consequently affecting the cheese yield and the sensory softness parameter.

Resumo Objetivou-se com este estudo comparar funções matemáticas no ajuste da curva de lactação média e individual de caprinos e estimar parâmetros genéticos e ambientais para medidas repetidas de produção de leite. Foram utilizadas 183 lactações, sendo 121 de cabras Saanen e 62 de cabras Alpinas, de animais pertencentes ao Laboratório de Caprinocultura e Ovinocultura da UFPB/CCHSA. O controle leiteiro foi realizado em intervalos de sete dias. O ajuste foi feito para curva média utilizando-se seis funções matemáticas: polinomial inversa, linear hiperbólica, gama incompleta, quadrática logarítmica, linear e quadrática, sendo ajustada por processos interativos, através de regressão não linear. Os critérios utilizados para verificar a qualidade do ajuste para cada função foram: coeficiente de determinação ajustado (R2a), percentuais de desvio entre as produções totais observadas e estimadas, percentuais de curvas típicas, desvio médio absoluto e quadrado médio dos resíduos. Verificou-se que qualquer um dos modelos testados pode ser utilizado para estimativas da curva média, porém, para o estudo das curvas individuais, o modelo Gama Incompleto deve ser preferido por apresentar melhores estimativas dos componentes da curva de lactação.

Abstract The objective of this study was to compare mathematical functions in adjusting the mean and individual lactation curve of goats and to estimate genetic and environmental parameters for repeated measures of milk production. 183 lactations were used, 121 of Saanen goats and 62 of Alpine goats, of animals belonging to the Laboratory of goat and Sheep of UFPB/CCHSA. The milk control was performed at intervals of seven days. The adjustment was made to the mean curve using six mathematical functions: inverse polynomial, linear hyperbolic, incomplete gamma, quadratic logarithmic, linear and quadratic, and adjusted by interactive processes through non-linear regression. The criteria used to verify the fit quality for each function were adjusted coefficient of determination (R2a), percentages of deviation between observed and estimated total yields, percentages of typical curves, mean absolute deviation and mean square of residues. It was verified that any of the models tested can be used for mean curve estimates, but for the study of the individual curves, the incomplete gamma model should be preferred because it presents better estimates of the components of the lactation curve.