A1- and A2-Milk and Their Effect on Human Health

Milk proteins are a heterogeneous group of polymeric compounds that have a wide range of different molecular structures and properties. They occur as caseins, whey proteins, enzymes, minor proteins and nitrogen compounds. Caseins constitute about 80% of the total proteins of cow’s milk. β-casein is an important part of the caseins, which makes up about 37% of the total caseins. Within β-casein, there are a number of variants which are genetically determined. However, there are thirteen genetic variants of β-casein found in cow´s milk. A1 and A2 are the most common variants, which are called A1 β-casein (A1-milk) and A2 β-casein (A2-milk). The only difference between A1- and A2-milk is a difference in the 67th amino acid in the chain. At this position, A2-milk has a proline amino acid, while A1-milk has histidine amino acid. Several studies have reported that cow’s milk with a dominant or singular A2-milk may be healthier than A1-milk. These studies are based on digestion of A1-milk which lead to release β-casomorphin-7 (BCM-7). Subsequently increase inflammation, Type-1-diabetes, heart disease, autism, gastrointestinal discomfort and other disease in the consumer. For this reason, there is a growing global interest in A2-milk. In conclusion, the effects of A1-milk compared to A2-milk on human health show mixed results. On the basis of the available results, we cannot conclusively assess the health effects of A1-milk and A2-milk. Therefore, further investigations are needed

Best combination of pre-stimulation and latency period duration before cluster attachment for efficient oxytocin release and milk ejection in cows with low to high udder-filling levels

Experiments were designed to investigate the suitability of a combination of a short manual teat stimulation with a short latency period before teat cup attachment to induce and maintain oxytocin release and milk ejection without interruption. In Experiment 1, seven dairy cows in mid lactation were manually pre-stimulated for 15, 30 or 45 s, followed by either 30 s or 45 s of latency period. It was shown that all treatments induced a similar release of oxytocin without interruption until the end of milking. In particular, the latency period of up to 45 s did not cause a transient decrease of oxytocin concentration. In Experiment 2, milking characteristics were recorded in seven cows each in early, mid, and late lactation, respectively. Because the course of milk ejection depends mainly on the degree of udder filling, individual milkings were classified based on the actual degree of udder filling which differs between lactational stages but also between morning and evening milkings. All animals underwent twelve different udder preparation treatments, i.e. 15, 30, or 45 s of pre-stimulation followed by latency periods of 0, 30, 45, or 60 s. Milking characteristics were recorded. Total milk yield, main milking time and average milk flow rate did not differ between treatments if the degree of udder filling at the start of milking was >40% of the maximum storage capacity. However, if the udder filling was <40%, main milking time was decreased with the duration of a latency period up to 45 s, independent of duration of pre-stimulation. Average milk flow at an udder filling of <40% was highest after a pre-stimulation of 45 s followed by a latency period of another 45 s. In contrast, average milk flow reached its lowest values at a pre-stimulation of 15 s without additional latency period. However, average milk flow after a 15-s pre-stimulation increased with increasing latency period. In conclusion, a very short pre-stimulation when followed by a latency period up to 45 s before teat cup attachment remains a suitable alternative for continuous stimulation to induce milk ejectio

Laboratory Tests to Optimize the Milking Machine Settings with Air Inlet Teat Cups for Sheep and Goats

Milking machine design and performance are directly related to the milkability of sheep and goats, with the aim of milking quickly, completely and gently. This leads to an increase in the milk yield with improved quality, and the maintenance of healthy udders. The aim of this study was to carry out laboratory tests to determine the optimal level of vacuum, pulsation rate and pulsation ratio of new milking machines in high and low milk lines for sheep and goats. This study was conducted at the Department of Research and Development, Siliconform, Germany. For this purpose, different levels of vacuum (32, 34, 36, 38 and 40 kPa), milk jet (2, 2.5, 3 and 4 mm), milk line (high line and low line) and pulsation ratio (50:50 and 60:40) were used. First minute water flow (1st WF/kg) was used as an indicator for assessing the best combination in the milking machine. In addition, the cyclic vacuum fluctuation was measured in the inner chamber of the teat cup during the 1st WF/kg with the aid of a Vacuscope device. Statistical analysis was conducted using the mixed procedure in SAS. Our results show that the vacuum level, the milk jet and the pulsation ratio had a significant influence (p < 0.05) on the 1st WF/kg in the two milking machines for goats and sheep. In conclusion, the ideal conditions for milking goats with air inlet teat cups in the milking machine are a vacuum level of 36–38 kPa (low line) and 38–40 kPa (high line), a pulsation rate of 90 cycles/min and a pulsation ratio of 60:40, while the ideal conditions in the sheep milking machines are a vacuum level of 35–36 kPa (low line) and 36–38 kPa (high line), a pulsation rate of 120 cycles/min and a pulsation ratio of 60:40 or 50:50

Milk Properties and Morphological Characteristics of the Donkey Mammary Gland for Development of an Adopted Milking Machine&mdash;A Review

Donkey milk (DM) has been known in the world for 5000 years for its benefits for human nutrition and health. Nowadays, DM has become more and more attractive as a commercial product. DM contains several physiologically functional components, including high-quality whey proteins, vitamins, important minerals, unsaturated fatty acid and bioactive components. Therefore, it is not only consumed as food but also as a remedy. The average daily milk yield of a female donkey over the entire lactation season was 1.57 &plusmn; 1.12 kg/day and fluctuated between 0.20 and 6.00 kg/day. Average milk concentrations (&plusmn;SD) of fat, protein, lactose, total solids and ash in DM were 0.63 &plusmn; 0.41%, 1.71 &plusmn; 0.24%, 6.34 &plusmn; 0.37%, 9.11 &plusmn; 0.95% and 0.39 &plusmn; 0.04%, respectively. Interestingly, DM is similar in composition to mare&rsquo;s milk, and both are similar to mother&rsquo;s milk. The anatomical and morphological properties of the mammary gland of the female donkey are special and can be compared with those of mare udders. However, the cistern cavity of the mammary gland of female donkeys is characterized by the presence of multiple pockets that open directly into the teat, instead of a single cistern cavity. Therefore, the mammary gland capacity in donkey mare is low and milking technique and routine are of most importance. So far there is no special milking machine for female donkeys and mares. The milking machines used nowadays were initially designed for smaller sheep and goat udders. The company Siliconform, Germany, has set itself the task of developing an optimized milking machine for donkey mares, which is adapted to the anatomical and morphological properties of the donkey mammary gland. Furthermore, it should achieve a physiologically ideal milking process meeting high animal welfare standards for increased milk production with high quality standards

Milking Machine Settings and Liner Design Are Important to Improve Milking Efficiency and Lactating Animal Welfare—Technical Note

The purpose of milking machines is to harvest milk at optimal quality and speed, while maintaining animal comfort and teat defense mechanisms against invading mastitis pathogens. Therefore, the milking machine is a very important piece of equipment on dairy farms to maintain a long healthy lactation by following the physiological conditions of the udder. The mechanical forces during long-term machine milking processes lead to changes in the teat tissue. This effect is related to the degree of adaptation of the milking machines to the physiological requirements of the individual udder anatomy and the physiological conditions of the lactating animals. If both, milking machine settings and liner design are not suitable for all teats and animals on the farm, some animals will not be fully milked, the teat condition will deteriorate over time and in the end, they may suffer from mastitis. Therefore, maintaining healthy udders and teats during milking is a central key component of an effective milking machine to produce good milk yield with higher quality by preventing mastitis and maintaining animal health and welfare. On large and thick teats, conventional liners often fit too tight, causing a massive mechanical stress load on the tissue. On small teats, however, they often do not adhere sufficiently close to the teat which can cause a considerable air admission and hence liner slips. The new liners, “Stimulor® StressLess” (Siliconform, Türkheim, Germany), have a wave-like lip construction and adapt well to the different teat sizes in a herd, thus ensuring consistent milking of lactating animals. A proper milking machine accommodates all teat sizes and forms, has a low vacuum to effectively open the teat and to stimulate physiological milk release and letdown. In addition, the right pulsation rate will maintain a stable vacuum on the teat area during milking. In conclusion, an ideal milking machine adapts to the morphological, anatomical, and physiological characteristics of the udder and teats of the lactating animals and it should achieve a physiologically ideal milking process that meets high animal welfare standards and increases milk production with a high quality standard

Physiological Aspects of Milk Somatic Cell Count in Small Ruminants&mdash;A Review

The aim of this review was to focus on the physiological aspects of milk somatic cell count (SCC) in small ruminants (SM). The SCC is an important component naturally present in milk and is generally used as an indicator of milk quality and udder health in milk producing ruminants. SCC contains the following cells: polymorphonuclear neutrophils (PMN), macrophages, lymphocytes, and many milk epithelial (MEC) cells, cell fragments, and cytoplasmic particles/vesicles. PMN (40&ndash;80%) represent the major cell type in milk in healthy uninfected goats, whereas the macrophages (45&ndash;88%) are the major cell type in sheep&rsquo;s milk. However, dairy goats and sheep have an apocrine secretory system that produces cytoplasmic cellular particles/vesicles and large numbers of cell fragments, resulting in the physiological SCC limit being exceeded. It is obvious that the SCC level in milk of SM can be affected by various influencing factors, such as milk fraction, breed, stage of lactation, parity, type of birth, milking system, and others. An increase in the SCC above the physiological level not only indicates an udder or general health problem but reduces milk production, changes the milk composition, and hence affects milk processing. Moreover, the milking machine plays an important role in maintaining udder health in SM and stable SCC at physiological levels in the milk obtained. So far, there are no healthy or pathological physiological SCC levels defined in SM milk. Furthermore, a differential cell count (DCC) or even a high resolution DCC (HRDCC), which were recently developed for cattle milk, could also help in SM to gain deeper insight into the immunology of the mammary gland and find biomarkers to assess udder health. In conclusion, SCC is an indication of udder health or exposure of the udder to infectious agents or mechanical stress and should therefore always be considered a warning sign

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves