首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Effect of different level of roughage availability and contrast levels of concentrate supplementation on flavour of goat milk
Institution:1. Norwegian University of Life Sciences, Department of Animal and Aquacultural Sciences, P.O. Box 5003, 1432 Ås, Norway;2. Norwegian University of Life Sciences, Department of Chemistry, Biochemistry and Food Science, 1432 Ås, Norway;1. Alexandria University, Faculty of Agriculture, Animal and Fish Production Department, Alexandria, Egypt;2. City of Scientific Research and Technological Applications, Arid Lands Cultivation Research Institute, Livestock Research Department, New Borg El-Arab, Alexandria, Egypt;1. INRA, UMR1213 Herbivores, Site de Theix, F-63122 Saint-Genès-Champanelle, France;2. Clermont Université, VetAgro Sup, BP 10448, F-63000 Clermont-Ferrand, France;3. Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, Ceredigion SY23 3EB, United Kingdom;1. Department of Dermatology, University Hospital of Strasbourg, Strasbourg, France;2. Department of Biophysics and Nuclear Medicine, University Hospital of Strasbourg, Strasbourg, France;3. ICube, UMR 7357 University of Strasbourg/CNRS and FMTS, Faculty of Medicine, University of Strasbourg, Strasbourg, France;1. Grasslands Research Centre, AgResearch Ltd., 11 Dairy Farm Road, Palmerston North 4442, New Zealand;2. School of Chemistry and Chemical Engineering, Harbin Institute of Technology, 92 Xidazhi Street, Nangang District, Harbin 150001, China;3. Ruakura Research Centre, AgResearch Ltd., 10 Bisley Road, Hamilton 3214, New Zealand;4. Callaghan Innovation, 69 Gracefield Road, Lower Hutt 5010, New Zealand;5. Invermay Research Centre, AgResearch Ltd., 176 Puddle Alley, Mosgiel 9053, New Zealand;1. Departamento de Ciencias Agroforestales, Escuela Técnica Superior de Ingeniería, Universidad de Huelva, “Campus de Excelencia Internacional Agroalimentario, ceiA3”, Campus de la Rábida, 21819 Palos de la Frontera, Huelva, Spain;2. Departamento de Medicina y Cirugía Animal, Universidad de Córdoba, Campus Rabanales, 14104 Córdoba, Spain;3. Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008 Granada, Spain;4. Departamento de Ciencias Agroforestales, Escuela Técnica Superior de Ingeniería Agronómica, Universidad de Sevilla, Ctra. Utrera km 1, 41013Sevilla, Spain
Abstract:Rancid and tart flavours are the most common off-flavours in Norwegian goat milk. In a feeding trial, we examined the effects of different levels of concentrate and of supplementary hay feeding on the occurrence of these off-flavours. Forty-eight experimental goats grazed cultivated pasture in the lowland during spring and autumn, and mountain pasture in summer. Twenty-four of the goats were fed 0.2 kg/day of concentrate (low concentrate, LC) and the remaining 24 goats 0.7 kg/day (high concentrate, HC). Twelve animals in LC and HC groups grazed freely, while the remaining goats in the two groups were given feeding challenges (limited periods of roughage restriction and ad libitum hay feeding). This was done to examine the effect of differing roughage availability on milk flavour. The animals fed low level of concentrate and with free grazing represented the control group. During the challenge periods, the goats were kept indoors and fed 0.2 kg hay/day for 2 days (roughage restriction) or hay according to appetite for 2 days (ad libitum feeding). At least 10 days of uninterrupted grazing were allowed between the challenges. Milk samples for sensory and chemical analysis were taken at the end of the challenge periods.The level of concentrate feeding did not influence the flavour of the milk when the goats were on lush spring pasture. However, the low level of concentrate feeding (LC) increased the frequency of off-flavour during the mountain and autumn experimental periods (P < 0.05).In the end of the mountain experimental period when the frequency of rancid/tart flavour increased in all groups, the sensory quality of milk produced by goats fed hay ad libitum (S1) had better taste ratings (P < 0.001) than milk from goats that were grazing. When the goats were given restricted amounts of hay, they adapted to the treatment by reducing their milk yield. In the spring and mountain experimental periods, restricted roughage feeding resulted in higher fat content and better taste ratings, especially in the group fed low level of concentrate (LC/S1). However, this connection was not clear in the autumn.Probably, the goats are able to handle a negative energy balance as long as mobilizable body reserves exist, but start to produce milk with lower dry matter content and higher frequencies of rancid/tart flavour when the body reserves are empty and the energy deficit is still pronounced.It is concluded that increasing the level of concentrate and feeding hay supplements will reduce the frequency of flavour defects at times when grazing is suboptimal or the pasture is of medium or low quality.
Keywords:
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号