PRECISION LIVESTOCK FARMING: PROTOTYPING SENSOR-BASED APPLICATIONS

Somatic cell count (SCC) represents a marker to monitor the udder health in dairy ruminants. In a situation of non-specific illness, such as infections by microorganisms, shocks and/or injuries to the breast tissue, improper milking and environmental stress, the immune system sends in the breast the white blood cells and, consequently, milk presents an increase in SCC. An indirect method widely used for the estimation of the somatic cells is the measurement of the milk electrical conductivity (EC). The value of EC depends on several factors including the iones Na+, K+ and Cl-, which represent, in addition to lactose, the osmotically active components of milk. Portable and online EC meters are commercially available, however the correlation between EC and SCC is low both in sheep (R2 = 0.37) and cow milk (R2 = 0.39). The objective of this work was to study the relationship between the ione Na+ and the main components of sheep milk, in particular somatic cells. Moreover, a portable device for estimating SCC in sheep milk was designed. The study was conducted on 75 Sarda breed sheep, randomly selected from three different farms located in Sardinia (Italy). A weekly sample of 50 ml of milk was taken from each half udder during the morning milking. Sampling lasted from March to June 2015, and a total of 1,500 samples were analyzed. The milk components examined were: fat, proteins, lactose, pH, sodium chloride, urea (Milkoscan FT 6000, Foss Electric, Hillerød, Denmark), SCC (Fossomatic 5000, Foss Electric, Hillerod, Denmark) and the ions Na+ (Laquatwin B725, Horiba, NY, USA) in the ARA (Associazione Regionale Allevatori) certified laboratory (Oristano, Sardinia). Arithmetic means, standard deviations and Pearson correlation coefficients were calculated on the parameters. Values of SCC were transformed into natural logarithm to determine the relationship between sodium ions and SCC. The correlation between Na + and SCC corresponded to R2 = 0.76 (P <0.001). The prototype developed incorporates two containers which receives milk samples taken from each half udder. Each container has integrated inside two sensors, one to detect the level of Na+ in the milk and the other one to compensate the milk temperature. The mathematical model, loaded into the microcontroller by a firmware written in C / C ++, analyze the data and gives back the estimate of SCC level. The device is also equipped with a slot for memory card (SD card) that allows to storage the measured data. The portable device developed would allow farmers and stakeholders to monitor the ewes health status by periodically comparing the somatic cell counts of each half udder.