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The use of alternative plant proteins in place of the soybean meal protein in diets for farmed animals aims to reduce the extra-EU soybean import and partially substitute the GMO in the food chain. Among the possible alternatives, the heat-processed (flaked) faba beans appears interesting for dairy cow diet. Two consecutive experiments were carried out to test flaked faba beans as a partial substitute for soybean meal in the diet of Reggiana breed dairy cows producing milk for Parmigiano-Reggiano cheese-making. In both experiments a "Control" concentrate (12% soybean meal, no faba beans) was compared with a "Faba" concentrate (7.5% soybean meal and 10% flaked faba beans). Forages fed to animals were hay (mixed grass and alfalfa) plus mixed grass in experiment 1, hay only in experiment 2. Milk yield and quality and the characteristics of grab faecal samples as empirical indicators of digestibility, were similar between feeding groups. The milk urea content was slightly lower in the "Faba" group, particularly in experiment 2 ("Control" vs "Faba": 34.6 vs 32.9 mg/dL in experiment 1, P<0.1; 27.4 vs 23.4 mg/dL in experiment 2, P<0.01); the plasma urea content in experiment 2 confirmed the trend observed in milk (3.9 vs 3.0 mmol/L, P<0.01). The inclusion of faba beans, within the allowed limit of the Parmigiano-Reggiano Consortium for diet formulation, could represent a feasible opportunity for a partial substitution of soybean meal. [ABSTRACT FROM AUTHOR]

Six pregnant heifers, coming from a herd with a history of high concentration of Polychlorobifenyls (PCB) into the milk, were fed with a very low-PCB diet starting from the 6th month of pregnancy. After parturition cows were milked for at least 190 d with a maximum of 270 d. Diet was made of: corn silage (31.7% of DMI), dehydrated alfalfa (13.3% of DMI), grass hay (3.7% of DMI) and concentrate (51.3% of DMI). The average DMI was 23.12 kg/d. Milk production was recorded and samples of milk and blood were taken and analyzed for PCB (18, 28, 31, 52, 44, 101, 149, 118, 153, 138, 180 and 194 congeners) content using a GC-MS technique. The average milk yield (kg/d) of the 6 cows was 26.0, 22.5, 23.2, 24.5, 28.9, 29.3. The maximum PCB concentration of 100 ng/g of fat allowed by the Italian law was reached after 144-209 days of lactation. One animal after 204 days had a PCB concentration of 102 ng/g fat. If log10 of PCB concentration (ppb) in milk fat is regressed against days in milking (DIM) the following significant equation was obtained: log10 PCB (ng/g of milk fat)= 2.796 -0.00474 DIM; r2 0.72; P<0.01 The initial level of contamination is not the main factor affecting the time required in order for PCB to return to below the legal threshold of 100 ng/g fat, while daily milk yield significantly affects PCB excretion. Body condition and energy balance could be important factors affecting PCB excretion. In the presence of high contamination, about 6 months of lactation are required in order to obtain milk with a sufficiently low PCB content. Among the seven congeners considered by Italian legislation, PCB 101, PCB 118, PCB 138, PCB 153 constitute almost all the PCBs found in tissues and milk, with a much smaller presence of PCB 180, and the numbers of the congeners PCB 28 and PCB 52 are almost insignificant, probably because they accumulate little in the body. The congeners PCB 138 and PCB 153 are those most frequently found. For PCB 138 the liver is the principal organ of accumulation, while for PCB 153 we found equal accumulations in the liver, kidneys and tail, but a low presence in milk. The PCBs 118 and 138 are those most abundant in milks. [ABSTRACT FROM AUTHOR]