Effect of mid-line or low-line milking systems on lipolysis and milk composition in dairy goats

Two experiments were carried out to investigate how milking in mid-line (ML) affects the lipolysis level and milk composition in goat livestock, in comparison with low-line (LL) milking. The first experiment took place, in triplicate, on an experimental farm. For each replicate, a crossover design (62 goats, two treatments, ML and LL, in two periods each lasting 4 days) was used. Milk samples were taken daily at 0 and 24 h after milking. In the first experimental replicate, some enzymatic coagulation cheeses were made, which were assessed by a panel of tasters at 50 and 100 days of maturation. In the second experiment, the lipolysis level and composition of tank milk from 55 commercial dairy goat farms (25 ML and 30 LL) were analysed, in milk samples taken in three different weeks. The results of the first experiment showed that ML milking increased free fatty acid (FFA) concentration in raw goat's milk significantly (0.71 v. 0.40 mmol/l, respectively). However, in the milk samples taken from commercial farms the FFA concentration remained unaffected by the milking pipeline height (0.59 v. 0.58 mmol/l for ML and LL, respectively). No significant differences were found in the milk composition, nor in the sensory characteristics in the cured cheeses, which suggests that factors other than the milkline height are able to influence the level of lipolysis under commercial conditions. Therefore, ML milking should not be discouraged, provided that the correct functioning and management of the milking operation and milk storage on the farm is guaranteed.

Effect of organic farming on selected raw cow milk components and properties

Organic dairying is an alternative for friendly exploitation of environment. This paper was focused on impacts of organic dairying on milk composition and properties. The conventional (C) cow milk was compared to organic (O) milk. Holstein bulk milk samples (BMSs) from winter and summer season in 4 C and 4 O (n = 32 and 32 BMSs; 2 years) herds were investigated. 6 herds were grazed and 2 C herds were not grazed. Mean O cow milk yield (MY, 305 lactation days) was 7037.3 ± 421.5 and C MY 7015.8 ± 1068.1 kg. Higher values (P < 0.05) in O milk had: log acetone (0.7321 > 0.6048); titration acidity (8.34 > 7.82 ml 0.25 mol.l−1 NaOH); alcohol stability (0.6 > 0.44 ml); time for enzymatic coagulation (150.75 > 115.03 second); whey protein (0.54 > 0.49%); fat/crude protein (1.2 > 1.15); milk fermentation ability (FAM) by titration (31.45 > 22.18 ml 0.25 mol.l−1 NaOH). Lower values (P < 0.05) in O milk had: solids–not–fat (8.64 < 8.73%); urea content (19.91 < 29.03 mg.100ml−1); electrical conductivity (3.66 < 4.08 mS.cm−1); whey volume (32.03 < 34.53 ml); crude protein (3.16 < 3.25%); casein (2.47 < 2.58%); non–protein nitrogen compounds (0.15 < 0.18%); urea nitrogen in non-protein nitrogen ratio (40.81 < 49.0%); casein numbers for crude protein and true protein (78.12 < 79.58 and 81.99 < 84.11%); coli bacteria count in normal and logarithm form (330.56 < 1502.92 CFU.ml−1 and 1.484 < 2.5823); actual yoghurt acidity (4.71 < 4.8). O cows suffered probably from lower energy and nitrogen compounds intake due to feeding under mentioned conditions. O milk could be a little better environment for yoghurt cultivation.

Impact of Different Milk Yields on Milk Quality in Bohemian Spotted Cattle

The milk yield (MY) is a significant economic and health factor. MY influences the health state of dairy cows, their reproduction performance, longevity and milk indicators (MIs). Differences within MIs between 2 higher (1; 8 348 kg per lactation; 240 individual milk samples) and 2 lower yielding herds (2; 7 344; 239) of Bohemian Spotted dairy cows (B) were tested. Sampling was carried out during summer and winter feeding seasons. Lactation factors were well balanced. Group 1 was on a higher genetical level, had better nutrition and higher MY by 13.7% (P < 0.001). All herds were milked twice a day. Twenty-three MIs were examined and 39.1% (9 of 23; 30.4% it was formerly in Holstein (H) with higher MY by 30%) were influenced (P < 0.05) by relatively smaller difference in MY: fat; log somatic cell count; urea (U); acetone (AC); alcohol stability; time for enzymatic coagulation; whey volume; ratio of urea nitrogen in nonprotein nitrogen (URN); fat/protein content ratio. It shows a higher susceptibility of B cows to the impact of higher MY on lactation physiology than H. Most changes were in more important MIs, usually with higher differences compared with H. The whole milk protein spectrum was not influenced (P > 0.05). The U was higher (5.707 > 4.365 mmol l-1) in group 1, AC and URN as well (0.0362 > 0.0238 mmol l-1 and 51.94 > 41.97%). It corresponds with nitrogen and energy metabolism.