This page describes the properties of milk protein
Another component whose reduction might be desirable is lactose. This may be accomplished through the production of an enzyme such as beta galactosidase in milk. Beta galactosidase breaks up lactose into the two simple sugars glucose and galactose. Producing a lactose free milk at the animal level may allow for the production of lactose free dairy products without having to modify the milk in the dairy plant.
This page describes the properties of milk fat
Other major factors contributing to uncertainty in hormone content/concentration include the breed of cow, time of year, stage of the lactation cycle and what the cow was fed. The composition of milk very definitely reflects the diet from which it is produced. High-percentage grain diets and production-enhancing hormone injections increase the volume of milk produced, but dilute overall levels of nutrients and can skew growth factor content upward. Since none of the studies mentioned the diet composition of the cows whose milk they examined, the variation in results came as no surprise.
The Estrogens: An important and often controversial class of steroid sex hormones including and usually associated with females, but present, and with important functions in males as well. Aside from their obvious influence on breast and uterine development, the estrogens (which are actually derived from the male sex hormones or 'androgens' and ) bolster bone maturation, strength and density, regulate formation of sperm cells and play crucial roles in fat (lipid), circulatory, respiratory and nervous system metabolism. The trace amounts present in bovine milk are considered too low to exhibit any physiological activity. , also present in raw milk, has an inhibitory effect on the estrogens. Estradiol: 160 pg/ml, Estrone: 34-55 pg/ml
Human Physiology - Cell structure and function - EKU
Peak yield is the point where the cow reaches the highest milk production level during the entire lactation. Heifers peak at 70-75% of mature cows and second lactation cows peak at 90% of mature cows. Normally, the peak is reached four to ten weeks after calving. The time it takes to reach peak yield varies with many factors, for example breed, nutrition and yield potential. Higher producing animals tend to peak later than low producing ones. A high peak yield normally means a higher total yield. Research shows that each one kilogram increase in peak yield usually means an additional 100-200 kg of milk produced during the actual lactation. Reaching high peak yields requires a very well managed and balanced feeding programme.
Because the shape of the lactation curve is fairly constant, milk yield in the early portion of the curve can be used to predict milk yield for the entire lactation period.
Analysis of lactation curve shape is helpful in identifying feeding and management problems within a dairy herd.
The cyotoskeleton represents the cell's skeleton
After calving, lactation continues for an extended period, in the dairy cow typically 300 days. Hormonal influences are critical to the maintenance of lactation. A few weeks after parturition the cow will begin her oestrus cycle again and show heat. She will be usually be artificially inseminated at an appropriate heat around 70-90 days after calving. The objective is to get the cow calving about once per year. Milk yield declines as pregnancy progresses. In fact the hormonal changes during pregnancy and the increasing flow of nutrients diverted towards the foetus serve to down regulate milk secretion.
At around 300 days milking is usually stopped and the cow “dried off”.
Synthetic - definition of synthetic by The Free Dictionary
The effect of ambient temperature on milk yield is dependent upon the breed. Holsteins and the other larger breeds are more tolerant to lower temperatures, whereas the smaller breeds particularly the Jersey, are much more tolerant to high temperatures. The optimum temperature for the Holstein cow is about 10 °C. Milk production declines when the environmental temperature exceeds 27 °C. The reduction in milk yield is largely due to a drop in feed intake. High temperature affect high producing cows more than low producers and it is particularly harmful during the peak of lactation.