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.