FARM AND DAIRY.

Taranaki Daily News, 23 April 1917, Page 8

FARM AND DAIRY.

MILK AND MILK MAKING. _ The averagei dairyman knows very little of the process of milk-making, as performed by her Majesty the Cow. He will find it immensely to his advantage to study closely and ponder deeply tlie following notes from Pcnlington's Science of Dairying:—■ BLOOD SUPPLY OP THE UDDER.

The material from which milk is made is originally obtained from the food which is digested in the alimentary canal. It enters the blood stream, qnd is conveyed to the udder By a large blood vessel called the mammary artery. [VALUABLE INFORMATION. It is good for a vendor of any partiJar commodity to know all there is to know about the article lie sells. On nearing the udder this artery divides and subdivides into many branches, which form a fine network of capillaries all through the udder. The contents of these capillaries are then collected into large veins, through which the blood is carried back to tlie heart. These Tjeins are called milk-veins; although, of course, they contain blood, not milk. They can easjjy be felt by passing the liand along the cow's 'body slightly forward of the udder. In good dairy cows these veins are very prominent. The size of the milk-veins is an indication regarding the amount of blood which is supplied to the udder, and So large veins are a good sign. If we follow the milk veins as far forward as possible, we find that they suddenly disappear into openings in the body wall, which can be easily felt with the finger. These openings are known as the "milk wells" or "milk fountains." There should be one of these milk wells for each branch of the milk veins. To a certain extent they regulate the capacity of the veins, and so large openings are very desirable. If too small, they will restrict the flow of blood and consequently diminish the production of milk. STRUCTURE OP THE UDDER AND FORMATION OF MILK The udder is a bag of tissue which hangs beneath the hind part of the cow's bodj. Its. internal structure is very compter. The greater part of the substance of the udder consists of a soft, spongy, greyish-pink mass, which is made up of muscle, blood vessels, nerves and fat. Above each of the teats,' which are generally four in number, it a mil): reservoir. As tlie name indicates, the milk reservoirs are intended to contain the milk which is made in the other parts of the udder. Each reservoir lias a capacity of about one pint. A vertical partition runs lengthwise, from back to front, through the udder, and divides it into two distinct and similar parts, each of which is called a milk gland. These milk glands have a very complex structure. Small blood vessels and capillaries carry blood through every part of the organ, and together with them«i;e to be found large numbers of nerves, which regulate the flow of milk and control the formation of milk. The remaining substance of the milk glands consists chiefly of a large number of small round Vta?s known as gland lobules. These gland loMes are arranged very much like gra]»*s upon a stalk. Corresponding te thb main stalk there is a narrow tube as tlio mi'k duct. At intervals along this main milk duct smaller tubes branch out, and at the end of each of these branches we find a round gland lobule. (D# not confuse the ward "lobule" with "globule.") When examined under the microscope the iliside of each gland lobule is found to be lined with a largo number of small bodies called alveoli. They are round at one4nd, and taper somewhat to a neck at the other. These alveoli are very small, but they are most important, for it is in them that the milk is formed. In some peculiar way which is not quite understood at present the alveoli take from the bloorl and lymph those substances of which milk is composed, and pass them through the seek of the lobule into the branch milk duct. The milk e: te.-s the main duet awl then runs d»wn into the reservoir, where it remains intil the cow is milked. From the bof'osi of sach reservoir a tube leads down through the teat beneath, but the milk i» prevented from escaping by rings of muscle around the tube. Muscles of tkio 'yp- which keep a tube closed tlicy are oontracted are called jphiacter imiiilcs. Ore of th«m is found at the ,o > of each teat and a more powerful oar at h_ Wttcsi. Other spliineei muscles, kit jot bo veil developed, are found 'jfiu.dhg ilx moutlis of the Irc.s vhie'- onvey miik from the gland k>uloc i to th. •. The cow can Jiese ar.s;)n tr a very considerable ext- t, and if in ?, bad humor at milkiiig time dw vri'.l aire them te contract, a_d * hold ba.l (lie milk. If only f»r this reas«E cmv_ !_hs"ld be kindly treated. Some animals an naturally difficult to milk, bj: ma->y more have Iften made bo by harsh, treatment.

MILK IS MACE DURING MILKING. The reader may have wonderd how it is that a cow can give ten quarts or more at a milking when the total capacity of the milk reservoirs is only alout two quarts. The reason for this apparent impossibility is quite simple—the greater part of the milk is made during milking. The milk waiting in the reservoirs is small in quantity and poor in quaKty. The largest and richest portion is manufactured during the actual process of milking. Pressing the teats excites the network of nerves in the milk glands, and so causes the alveoli to perform their work with greatly increased vigor; drops of rich milk trickle down the milk ducts into the reservoirs. Hers, again, is a most important) reason for treating the cow kindly, especially at milking time. Not only can sho make herself difficult to milk by contracting the sphincter muscles of the teats, but she has also a good deal of power over

the formation of tlio milk in tlie gland lobules. Consequently, if put in a bact temper by unkindness she will retaliate by restraining the action of the milkforming alveoli, and so cause the farmer to lose much of the most valuable part top and pressing the teat against the ball ol' the thumb. Complete "stripping" is very important. If a cow is only halfmilked she will reduce her milk yield accordingly. Thorough milking develops the udder and helps to maintain a large milk yield.