Technologies for the improvement of animal welfare in relation to the quality of milk

Abstract

Objectives of the PhD project thesis were a) improving knowledge on relationship between quality of milk and welfare of cows in order to better characterize food in relation to the animal welfare as an important attribute of sustainability of animal productions; b) providing science based suggestion on how to preserve milk quality while improving quality of animal lives by using innovative technologies. Research activities focused on welfare of cow and calf around calving and birth that is the crucial phase in a dairy herd. The technologies currently available and their impact on animal welfare were studied. Livestock precision farming can provide real-time decision support systems helping producers to detect health and welfare disorders at an early stage and to improve management procedures. Automation of barn operations and precision livestock farming are key factors to improve husbandry and increase robustness of dairy sector, having the potential to increase milk yield and optimize process inputs meanwhile helping animal welfare. Automated systems are becoming widely used for milking, feeding and detecting oestrus in dairy cows while automatic systems for monitoring calving are still scarcely used. Careful monitoring of cows helps to minimize pain and distress during calving; moreover, knowing the exact time of birth is important to ensure timely assistance and the adequate ingestion of colostrum by the calf. However, direct visual observation is time consuming and the continuous presence of an observer during stage two of calving can disturb cows. Video cameras or accelerometers recording behaviour of cows can be integrated in systems using image analysis or locomotive activity to alert the farmer when calving is imminent. However, alerting systems require input of benchmark information about behaviours and changes in behaviours which can be predictive of the time of calving. Data from 24 hours videorecording of cows before delivery were analysed to identify the behaviours associated with an imminent birth. The only behaviour that was significantly influenced by the distance to delivery was posture changing (P<0.0001). Two hours before the delivery, the proportion of posture changes was different from all the hourly proportions measured from -24 to -3 hours relative to delivery (P<0.005), resulting 3.6 times the average of the previous 22 hours relative to delivery. Increase of posture changes may be an indicator of calving approaching, but further studies are needed to input benchmark values in alerting systems. The calf, at birth, has an immature immune system that reacts slowly to infections and therefore makes it more exposed to pathogens. Moreover, at birth the calf is free of the maternal antibodies which during gestation cannot cross the syndesmochorial placenta that is impermeable to the large molecules. Passive transfer of immunity is essential for the short- and long-term health of dairy calves. Colostrum is the first and most important line of defence for a newborn calf. The first immune protection is given by the immunoglobulins (Ig) that the calf ingest in the first hours of life through the colostrum produced by the mother. A portion of these immunoglobulins, once absorbed through the small intestine, provides protection against systemic diseases. Another part of immunoglobulin acts directly in the intestine where it can neutralize pathogens and prevent the development of diarrhea. With the colostrum the calf also takes the maternal lymphocytes that, through the intestinal mucosa, reach the different tissues and stimulate the development of immune system. The calf should take colostrum within 6 hours of birth, since the intestinal permeability to the IgG decreases with the time. Actually, the effective timing of administration of the first colostrum varies considerably between farms and within farms depending on the time of birth and the organization of work. In some farms the calves born at certain times of the day can have the first administration well over 6 hours after birth. A field study was carried out on two case study farms to better understand variability of colostrum quality and the feasibility of quality assessment at farm level. The information provided will be useful to prepare infographic and other educational material to promote better management of colostrum at farm level. The bibliographic review on association of animal welfare with milk quality showed evidences of relations between specific welfare issues of dairy cows and quality of milk; the best demonstrated links are the effects of mastitis and oxidative stress on composition, shelf life, sensory and technological characteristics of milk and milk product. Effect metabolic diseases on gross composition of milk is also well-known, but little is known about the effects on other milk characteristics which are of great importance: fatty acids content; mineral content; acidity and coagulation properties. The changes of milk composition during ketosis in dairy cows have been investigated by many decades providing consolidated knowledge about the effect of ketosis on fat; fat percentage and fat:protein ratio are used as indicator of risk of ketosis. However, the changes of fatty acids content; acidity and coagulation properties have been very little or not studied at all. A field study was designed to explore the variability of these parameters in relation to metabolic disorders, especially ketosis; the purpose of this pilot study was to provide preliminary information necessary to design a larger survey.