By Jan Bonsma
Chapter 2 from The Wortham Foundation Lectures in Animal Science
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After studying livestock, production in various parts of the world and after having had the good fortune of being a guest professor at Texas A&M University in America, I would like to describe some of my concepts of livestock philosophy.
During the past 3 decades I had the good fortune of seeing much agriculture and livestock production in various parts of the world. As a result of these observations, it became obvious to me that animal husbandry is influenced mainly by the cultural and religious background of the people who practice it. Throughout the world one finds that those races who are superstitious, ignorant and prejudiced are backward in their approach to livestock improvement and the betterment of agriculture in general. The Bantu tribes in Africa consider animals to be a token of wealth and a means of acquiring a wife. These people never have regarded livestock production as a means of benefiting mankind and a method of improving the nutritional standards of their people. They have never practiced systems of selection and improved breeding with the object of producing more and better food for their own people. Likewise, to the Hindu, whose outlook on the animal is holy. These people are not permitted to castrate useless bulls; hence, they carry out no system of herd improvement whatsoever. The people of the western civilization have a cultural and religious background which stimulates improvement in livestock production.
It is worthy to note that in the Bible in Psalms 8:5-8, David sang to the Lord,
“For thou hast made him a little lower than the angels, and hast crowned him with glory and honor. Thou madest him to have dominion over the works of thy hand: thou hast put all things under his feet; all sheep and oxen yea, and the beasts of the field; the fowl of the air, and the fish of the sea, and whatsoever passeth through the paths of the seas.”
On those people of the Western Civilization who practice livestock husbandry, these few verses place a tremendous responsibility as is illustrated in the words, ‘they are put under man’s feet’ That implies that it is the duty of Westerners and Christians to improve that which has been given them. If they fail to do so they are failing in their responsibilities as husbandmen, and, in the case of university professors and lecturers, in their duty of teaching improved methods of livestock production.
A wheel drawn in three dimensions is used as the illustration of this livestock philosophy. In this diagram, Figure 1, man is considered the axle of the wheel, and the animal is the hub. The domesticated animal is in close symbiosis with man. In other words, the animal is to a great extent dependent for its existence on the management and husbandry of man. The domesticated animal is in close symbiosis with man because it has been modified and changed during the processes of domestication.
There are no fewer than 3,000 species of mammals in the world, of which man has domesticated approximately 30. Animals must have possessed certain characteristics and qualities to enable man to domesticate them. Some of the more important factors are tractability, docility and the ability of the animal to produce animal products useful to man, such as milk, meat, mohair, wool and hides.
Man has domesticated
1) Equidae — horses and asses;
2) Camelidae — camels, llamas and alpacas;
3) Bovidae — cattle, buffalo, yaks, gayals and bantengs;
4) Ovidae — sheep and goats;
5) Cervidae reindeer; and
6) Suidae — swine.
It is my opinion that if human life is removed from this earth, the domestic animals, also within a relatively short period of time, will be extinct. Only animals which are really well developed from an adaptability point of view will be able to propagate and survive for a long time. Such exceptions are the few breeds of indigenous cattle, but the highly improved animals which are highly productive soon will become extinct.
In the symbiotic tie between man and his animals, the closer the tie, the stronger is their symbiotic relationship. In Holland, for instance, the Friesland dairy cattle and the cattlemen’s families live under one roof. The cattle are the air-conditioning mechanism during the wintertime which keeps the homestead warm. Man looks after these cattle by making hay, which he stacks on top of the barn to keep the cattle at a comfortable temperature- during the cold winters. This chain relationship between man and his animals is closely linked, and where these links are closer than average, the cattle usually are very highly developed, and functionally more efficient than in those regions of the world where the symbiotic tie is not so strong.
In my livestock philosophy, man is the most important environmental factor. Man can, within limits, modify certain external environmental factors and by breeding, selection and modification of the environment, breed cattle which are highly productive and well adapted to a particular region.
If the approach of man changes due to certain economic factors and he loses his incentive to breeding better livestock, the livestock improvement program will degenerate. That is a facet of livestock production in America which perturbs me. So many cattlemen in this country have completely lost the incentive to produce better livestock because they need not show a profit on their livestock enterprises; they have made money in other fields of commerce and industry. These men have gone into livestock production as a token of social and financial status and as so many of these production sales, which started off as honest endeavors to, distribute and disseminate superior germ plasm, have degenerated, into a social event where, materialistic power is demonstrated and where status and friendship is traded. It has completely lost the incentive of selecting and buying improved genetic material to use in the betterment of herds.
From the point of view of man himself, the three greatest obstacles to improved livestock production are ignorance, superstition and prejudice. It is my opinion that the breed societies who have fixed ideas about what the ideal type of livestock is and who have made their breed standards so concrete that no modifications can take place have reached a point where they cannot select desirable variants; hence, they cannot improve their cattle. These fixed clay idols are nothing but prejudiced visions of men who really hero worship an image not measured in terms of functional efficiency. Prejudice is the main factor which in many instances prevents die improvement and progress of certain breeds.
Ignorance is another factor detrimental to the improvement and welfare :of breeds and breed societies. It is absolutely essential if breed societies have an inspection system of their cattle by livestock inspectors that these livestock inspectors are well acquainted with modern trends in animal research. They must be well read and must regularly associate with scientists in other fields of animal production to enable them to judge animals on a logical and functional basis. A livestock inspector or a cattleman who is ignorant will not make the necessary progress in livestock breeding which is essential in keeping abreast of time.
Superstition also plays a role in retarding the progress in livestock production, and it is for that reason that so many of the backward people cannot produce functionally efficient livestock. People who are disinterested in animals will never make a success of animal husbandry. The successful livestock producer is one who knows his animals and who treats them with care and love. Only then will the hub be lubricated and move with ease around the axle of the wheel.
In this livestock philosophy, the environment is the running surface of the wheel — a large concentric circle immediately around the hub which is attached to the hub by spokes, each of which has a direct action on the hub. Each environmental factor having a direct influence on the animal is indicated as a spoke directed from the running surface of the wheel to the hub.
Nutrition, together with metabolism which affects the transformation of food into products such as meat, milk and eggs is probably the mightiest spoke in the wheel. The nutrition of the animal and the interaction between the feed and the animal is a living chemical and physical, reaction between the animal and its total environment. The quantity and quality of feed produced is environmentally controlled; there are no two environmental regions which produce feed, of the same nutritional value, and no two animals interact exactly the same on the feed.
Animal metabolism is closely correlated with, and influenced by external environmental factors such as temperature, light, radiation, wind, etc, and their catalytic action on the chemical reactions taking place in the animal. The interaction between the animal and the total environment depends on its hide, hair and color.
An animal’s color, coat cover, vascularity of hide and ability to maintain a normal thermal equilibrium in a specific environment greatly influences its metabolic rate and efficiency of food utilization. The animal’s internal environment, namely its endocrine function and physiological reactions also determine what, the coefficient of digestibility of the feed will be.
The ability of man to assess the nutritional status of a particular region and to exploit the adaptability phenomena exhibited by animals has enabled man to produce livestock where previously it was absolutely impossible to maintain them.
We only have to consider the advances man has made in connection with the feeding of pelleted hay, concentrates or rations with a low heat increment in areas where thermal, stress was too high for dairy cows to produce milk, In Israel, it was impossible as recently as 20 years ago to produce enough milk to supply public demands. Now, by feeding dairy cattle concentrated rations with a low heat increment, it is possible to produce an abundance of milk — in fact, the Israeli dairy cattle are highest milk-producing cattle per capita in the world.
It is, however, not possible for man to overcome the hazards of climate from a reproductive point of view by nutrition. It is probable that this hazard will also be overcome but at this date it is very definite that the cattle in Israel require more inseminations per conception than in most other countries of the world.
Energy for maintenance can be compared to a cooling ball used at Messina Research Station, Northern Transvaal, Republic of South Africa, to measure the energy input and energy loss from a bail painted the color of human skin. Electric energy was transferred from electric storage batteries to an electric coil in the ball. By controlling the flow of electric energy into the ball, it was possible to maintain an average temperature of 98:7° F. The slightest change in daylight hours or the passing of a cloud in front of the sun would immediately cause the cooling ball to radiate more energy; hence, more energy had to be put into the cooling ball to maintain a temperature of 98.7° F.
The energy input into the cooling ball was recorded by a galvanometer in gram calories per minute, and it became very obvious that weather fluctuations such as wind, rain, clouds or a sudden cold spell would immediately change the amount of energy dissipated by the cooling ball. From this concept it became clear that there is no such thing as a maintenance ration for an animal. The amount of feed or energy put into the animal is dictated by weather and climate and by the internal and external function of the animal. That is, the internal function, the endocrinology and the physiology have a marked influence on the efficiency of food utilization.
The surface which forms the contact between the animal and its external environment is the hide and hair. The vascularity of hide and the nature of the hair determine the rate of radiant energy dissipated from the animal’s body, and it is very obvious that animals which differ in coat color and cover and hide thickness definitely vary in their nutritional requirements in a particular environment. This also clearly illustrates that there is no universal breed regarding efficiency of food utilization in a particular environment. The object of the performance testing of animals and the determination of the efficiency of food utilization is based upon this interaction between the total environment and the animal. If we performance test animals, we try to measure which animals give the greatest return on the amount of energy put into the animal. Performance testing is a method to measure the relationship between energy input and output and to select the animals which are most efficient. It is a basic concept to breeding better livestock.
High temperatures are a serious problem to livestock production. Low temperatures do not constitute the same problem if the animal is supplied with sufficient food. The inflow of electric energy will maintain the temperature of the cooling ball despite cold wins or rain. If the radiating surface of the cooling ball is covered by material there will be less energy radiated. The nature of the external radiating surface of the animal such as coat color, coat cover, vascularity of hide and relationship of surface area per unit weight has a marked influence on the amount of radiant energy lost and on the animal’s adaptability.
At the University of Missouri, some experiments were carried out in which Zebu, Jersey and Holstein cattle were kept in rooms where the temperature varied from 5° to 105°F. The sleek-coated Zebu cattle, which have a relatively large surface area per unit weight, can withstand high temperatures very well. Low temperatures are less well tolerated as a result of greater radiating surface. These animals could not overcome cold as readily as cattle of the European, breeds. In a series of experiments: the animals were kept in psychometric chambers at a temperature of 65° F, and the food intake was measured. When the temperature was raised to 105c F, the animals showed acute symptoms of distress. When the temperature was lowered, to 5° the cattle showed no sign of real distress. The result of this experiment showed that at 5° F. the Holsteins consumed 8 percent more food, the Jerseys 26 percent more and the Zebus 36 percent more than what they respectively consumed at 65° F. Although Zebu types (Bos Indicus) could withstand the cold and were not uncomfortable, they had to consume appreciably more food than did the British breeds (Bos taurus) in order to maintain their heat balance at 5° F. Extra energy had to be given the animals which had a more effective radiating surface to enable them to maintain their thermal equilibrium.
The coefficient of digestibility of feed is greatly reduced by high atmospheric temperatures. In preliminary tests on rats kept on a constant well-balanced ration, it was found that the coefficient of digestibility of the ration was 72 percent at 85° F and that it was reduced to 59 percent at 85° F. At 105° F. the appetites of all the animals were greatly reduced and all showed symptoms of distress.
Since temperature plays such an important role, an attempt has been made to develop a new type of animal adapted to the hot climate such as prevails at Mara Research Station, Northern Transvaal, Republic of South Africa. Animals should be bred in such a way as to promote their adaptability to high temperatures. For this reason, all cattle which are to be adapted to a high environmental temperature must have certain characteristics which enable them to maintain thermal equilibrium on hot days. Here again the basis of selection should be determined by research. In an endeavor to determine which animals are more adaptable, man must measure, correlate, interpret, select and breed. It was found from research work done on tropical and subtropical adaptation of cattle that certain morphological characteristics are closely associated with the ability of the animal to maintain a thermal equilibrium in hot environments. The most important factors to select for are the following: The animal must be sleek coated and must have hair that is medullated — only one hair must come out of each primary hair follicle. The animal must have a thick, pigmented hide having a high degree of vascularity. Those animals with movable hides that exhibit downward skin folds have a high vascularity of hide. The amount of dewlap and development and naval fold is not significant where adaptability is concerned. Animals should be able to move freely to obtain nutrients from areas where the climate is semiarid and where vegetation is sparse. Only animals which move with ease and which can maintain a thermal equilibrium are able to sustain themselves under such conditions.
Also, if it is possible, the hemoglobin index should be measured. Animals that are tropically adapted usually have a high hemoglobin index.
Beef cattle such as the Brahman (Bos Indicus) and the Afrikaner (Bos Indicus) are well adapted to the high temperatures in subtropical areas. However, these animals are slow maturing and often are sub-fertile. By crossing cattle of the Bos Indicus breeds with the British breeds of livestock such as Shorthorn, Hereford, Aberdeen Angus or Sussex, desirable genetic traits from both species of livestock can be combined and new breeds can be created, such as the Santa Gertrudis, the first “man made” American breed of livestock, and the “Bonsmara” in South Africa.
Light is the most constant of all weather and climatic conditions. At the same location, the atmospheric temperature on a particular day may vary greatly from year to year, and light intensity may vary slightly, but light duration remains constant at comparative dates of different years. Light rays cause an impulse or stimulus on the pituitary gland and hence, a reaction by which the animal sheds its hair. As the days become shorter and the nights longer, cattle begin growing longer hair and develop winter coats. Conversely, as the nights shorten and the days lengthen, they shed their winter coats and become smooth coated.
In Britain the difference between the longest days in summer and the shortest days in winter is at least 12 hours; in countries in the Southern Hemisphere such as South Africa this difference is approximately 2 hours; and on the equator there is a difference of 2 minutes between the longest and shortest days.
Those animals which shed their winter coats and become smooth coated early in spring can adapt themselves, and breed regularly in a subtropical environment. In research work done in the photo-period rooms at the University of Pretoria, Republic of South Africa, it was shown that animals with smooth coats and which sleek off readily with changing light stimuli have a higher gonadotropic content in the blood than those that maintain their woolly coats,
A smooth-coated Hereford herd was bred at Mara in the Northern Transvaal by using only animals that reacted to a stimulus of only 3 hours difference in daylight between the longest and shortest clays of the year. By selecting those early hair shedders in spring, it was possible, in approximately 15 years, to build, up a smooth-coated, thick-hided herd of Hereford cattle. Four smooth-coated, Hereford heifers were transferred from Mara Research Station to Mpapwa Research Station in Tanganyika approximately 250 miles south of the equator. As a result of the slight difference between daylight length during summer and winter, these heifers did not shed their hair at Mpapwa. It is very definite that light acts as a catalyzing agent with regard to the metabolism of food in the animal. In the photo-period rooms at the University of Pretoria, it was possible to change the rate of hair shedding by changing the photo-period in the rooms, and it also was possible to change the gamma globulin content of the blood. Animals maintained in the dark had superior marbling to those maintained in the light.
Light has a very marked influence on the metabolic rate of animals. For this reason extra light is used in chicken houses to facilitate rapid feathering and earlier egg production. It also is used in broiler production, and rapid alterations of dark and light stimulate the amount of food consumed and hence increase growth rate. The marked influence light has on animals has been clearly demonstrated by German scientists who placed pigeons in light bell jars and others in dark bell jars. All the pigeons were deprived of food. The pigeons in the light bell jars died after 12 days while the ones in the dark bell jars survived, for 24 days.
It is my opinion that more research should be done in connection with the influence of the photo-period on various physiological reactions of animals. It is one of the most important factors influencing the sexual activity of animals. In the research work on the sexual activity of cattle in the subtropics and tropics, it was found that the cattle showed higher sexual activity when the daylight and night hours were equal. The influence of light on sexual activity and how this will affect animals which are transferred through several degrees of latitude is most important where cattle are shipped from one hemisphere to another.
During the war years, cattle were transferred from the Southern Cape area in South Africa to Messina Research Station in Northern Transvaal. This change of environment through 100 of latitude caused the animals which cycled normally in the southern part of South Africa to stop cycling. In the group, 16 Shorthorn heifers never cycled for approximately 1 year. The 16 Afrikaner heifers in this group did not come in heat or show estrus for approximately 10 months. After more than a year, 12 of the 16 Afrikaner heifers were in calf, but only 4 of the Shorthorn were settled.
If animals are transferred from one environment to another and are brought through 10 or more degrees of latitude, the normal periods of estrus are upset and animals will not come in heat in; many instances for as long as a year. If cattle are transferred from the Northern Hemisphere to the Southern Hemisphere, for instance, from the United States to the Argentine, it would be best to transfer young animals which are pregnant for the first time. The transfer should be made when these animals are approximately 3 months pregnant. Results obtained in transferring cattle from one hemisphere to another indicate that the normal reproductive processes are impaired. Many animals will become completely sterile, and many will not exhibit estrus for as long as a year.
Animals taken from the northern part of the United States and transferred to the Argentine will take appreciably longer to adapt themselves than those transferred from Southern states such as Florida, Louisiana or Texas. It also is necessary to transfer the cattle from the United States to the Southern Hemisphere during the American autumn so that those animals arrive in the Southern Hemisphere during spring. That is when the daylight is on the increase.
Cattle transferred during the winter from Colorado, Kentucky or states further north will have long outer protective coats, woolly inner heat retaining coats (winter coats) and such animals will not readily shed their hair during the summer in southern United States. It is absolutely essential, if transfer of cattle is made, to select sleek coated animals.
The woolly coated animals transferred from the Northern Hemisphere to the Southern Hemisphere will never become absolutely sleek coated because the difference between summer and winter daylight length in the Northern Hemisphere is much greater than the difference between summer and winter daylight length in the cattle producing regions of the Southern Hemisphere. In the Northern Hemisphere there are approximately 12-14 hours difference between summer and winter daylight, and this large difference stimulates these animals to shed their hair and become smooth coated. The woolly coated animals of the Northern Hemisphere will not react to the stimulus of approximately 2-5 hours difference in the summer and winter daylight as is usually experienced in the cattle regions of the Southern Hemisphere.
It also is advisable to transfer cattle through degrees of latitude, that is from North to South or vice-versa, during early spring. In the research work done in the photo-period room at the University of Pretoria, Republic of South Africa, it was shown that the gamma globulin content of the blood increased during increasing daylight, and it probably would be advisable to immunize cattle during the spring. If cattle are transferred from America to Latin America, it would be easier to immunize them during the South American spring.
In the work done in the photo-period room at the University of Pretoria, animals that sleek off readily as a result of the changing photo-period have a higher gonadotropin content than those which do not become smooth coated. It always is advisable to select animals which are early hair shedders in spring. If exports of cattle are to be made from Britain to the Republic of South Africa or from the United States to the Latin Americas, it will be advisable always to select sleek-coated animals.
Various colors in animals will react differently to light intensity. Where light intensity is low, dark colored cattle will have a higher metabolic rate than light colored ones; hence, in thickly forested regions I would prefer dark colored cattle. Light cannot be separated from radiation because light is composed of the various spectra, namely red, orange, yellow, blue, indigo and violet, and the infrared rays are heat rays and the ultraviolet rays are the chemical rays, hence light intensity is in many ways correlated with the effects of radiation.
Sunlight comprises a series of rays differing in wave length, composition and action. If sunlight is split into the spectrum and thermometers are placed in the various segments, temperatures will become progressively higher from violet to red. The hottest spot of the spectrum is the invisible section just beyond the red, namely the infrared. The red rays are heat rays and when they impinge on the animal’s hide they make it warm; so warm on a hot day in the case of some black cattle that one cannot touch them. During the hottest part of the day most animals require shade, one of the limiting factors on many ranches. More trees should be planted, or shelter provided for animals to enable them to find shade and avoid the problem of infrared radiation.
In open Savannah country where the infrared radiation is intense, it is considered that red cattle with pigmented hides or white cattle with pigmented hides will be better able to radiate energy and utilize the nutriment of that particular environment more efficiently than other cattle. In, a hot climate radiant heat energy absorbed by the body must be dissipated before the animal can consume sufficient food for maximum growth.
Light waves also cause chemical reactions. Effects of the ultraviolet beam are demonstrated when animals are exposed to high altitudes, it is very obvious that animals which do not have pigment in or around the eyes suffer from eye cancers. If an animal is predominantly white or with areas lacking pigment in the hide, as in the case in some British breeds, ultraviolet rays cause hyperkeratosis of the hide and the animal suffers severely. ‘White pigmentation in an animal is a great hazard in areas where ultraviolet impingement is intense, as at high altitudes or in regions where the sky is often slightly overcast. The hair color and the hide and its functioning are most important in those climatic zones where ultraviolet radiation is intense. The hide is a temperature regulating organ containing a thermostat which efficiently can control the body temperature of the animal, and it also supplies sebum which will enable the animal to overcome the ill effects of ultraviolet radiations such as hyperkeratosis.
Much research work needs to be done on how an animal’s color influences its adaptability to overcome hazards of ultraviolet radiation and infrared impingement. In those areas where ultraviolet impingement is intense, a white color or even white areas in which there is no pigment in the hide constitute a definite hazard to the animal. The white animal with strongly pigmented hide well supplied with sebaceous glands can overcome the hazards. Zebum has a screening or filtering effect upon the ultraviolet radiation. The combined effects of light and radiation may cause animals to become photosensitized when they consume certain plants; for instance, in the case of sheep, goathead, Tribules terestis, will cause disease. It also will cause the sloughing of the white areas of the hide in cattle. Cattle which consume lantana will become severely photosensitized, the mucous membranes of the body will become terribly irritated and such animals usually die. Sandburn in horses also is a condition where photosensitization is caused by the eating of a plant.
Altitude has a direct influence on man and animals; for every 1,000 feet increase in altitude there is an average decline of 3° F. At high altitudes, the temperature usually is lower than that of lower lying surrounding areas on the same degree of latitude.
High altitude also has an influence on the oxygen tension of the atmosphere. In the Andes Mountains, many European organizations attempted to settle at altitudes of 11,000 feet and higher. However, they found that men could work there for a while but the women could not work at all as they could not stand the rarified atmosphere. The Inca Indians live in this region. The men weigh an average of 114 pounds. These people have tremendous chest capacity; hence, they can utilize the oxygen in the rarified air better than other people who are not so well adapted. In breathing they must inhale a tremendous volume of air to obtain sufficient oxygen to feed their tissues. At those high altitudes where the soils are usually acid, potatoes grow well although they are of low nutritional value. In general, crops grown at high altitudes are very low in calcium, hence the small stature of the people.
Soil pH usually is low at high altitudes, usually resulting in the development of animals of small stature. An exception is the high soil pH in the valleys of the Swiss Alps where large Brown Swiss cattle are produced. Some animals can live at high altitudes better than others. One of the most important is the llama, which has a red blood cell count twice that of man, and the affinity of the blood for absorbing oxygen also is twice as efficient as that of human blood. What has this to do with animal breeding? The Swiss worker, Duerst, and his associates many years ago found that cattle in regions of high altitudes, such as the Brown Swiss cattle, have the highest blood counts of all breeds. The tropical adaptability of the Brown Swiss centers around this point, since at high altitudes and in areas of high temperature the animals contend with the problem of rarified air. Further mutual similarities between high altitudes and subtropic conditions are that at high altitudes ultraviolet impingement is great, such as in the tropical regions. Infrared radiation also is intense, and the dark colored animal is preferable at the higher altitude where infrared radiation is required as a source of energy. In the tropics, however, infrared radiation is not required as a source of energy and therefore is a problem. Because of the occurrence of intense ultraviolet and infrared radiation at high altitudes and in the subtropics, similarities between animals of the two environments are apparent. In most high altitude regions where indigenous cattle are encountered, these cattle usually are dark brown or black in color. There is no doubt that, at high altitudes, light hair color and hides which lack pigmentation are definite hazards to animals. At high altitudes the incidence of eye cancer in cattle such as the Hereford also is very intense. Windy days are more frequent at high altitudes and wind acts as a cooling agent to these animals. The problem of wind is not nearly so severe in South Africa as it is in New Zealand or in the north of Scotland.
On the eastern seaboard of New Zealand where wind blows continuously, cattle are inclined to have appreciably longer hair-than in regions where wind is less often encountered. It also is a well-established fact that in an endeavor to grow long curly hair on Hereford cattle for show purposes it is only necessary to use atomized water and blow it over the animals with a strong fan. Moist wind will stimulate hair growth in animals. At high altitudes and in regions where cattle have to endure moist cold winds, they usually grow very long hair. A typical example is the Scots Highlander. The animals grow two types of hair: an inner heat retaining coat, and an outer protective coat. These two coats have different electrical charges, and when wind blows over the animal the hair packs tightly as a result of the increase in the difference between the charges. The coat becomes impermeable to moisture and wind, and the loss of energy is reduced.
In high altitude areas such as the High Veldt of the Transvaal in South Africa, where the average altitude above sea level is over 4,500 feet, animals lose weight rapidly during cold spells. If animals are to overcome the cold, they must be provided with more heat, ie., extra feed. It also is certain that in areas where animals are adapted to the subtropics and which have sleek coats die in greater numbers during a cold spell because of the rapid energy loss, regardless of stored fat. Shelter also is considered very important at very high altitudes.
DISEASE AND PARASITES
The problem of disease in livestock production often can be relegated into the background if the animals are well adapted to the environmental conditions in which they are maintained and if they are well nourished. It is certain that by proper management and good nutrition the disease factor will become less important. In a series of experiments done at the Onderstepoort Veterinary Laboratories in South Africa on badly worm-infested sheep, one-half of this group was properly fed while the other half was poorly nourished but treated with wormacides. Results showed that the properly nourished sheep were free from internal parasites long before the others. The malnourished animals became prey to internal and external parasites.
During 1940-42, a study to determine tick repellency on different animals showed that adaptable animals with slick smooth coats, thick movable hides, and a sensitive pilometer nervous system were relatively free from ticks and were in good condition. Cattle which lacked adaptability had thin hides and were woolly coated, were infested with ticks.
Disease has been relegated into the background in this philosophy as it is not a major problem if management is correct with regard to nutrition and prophylactic immunization and if animals are bred which are adapted to the environment.
The problem of parasites in livestock production also has been greatly overcome in many instances. An example is the almost complete eradication of the screw worm problem in Texas and other southern states. When such a vast ecological change such as the complete eradication of screw worm has been brought about in a particular environment it will become essential to do new ecological research work to reorient the whole livestock production situation in these environments. As a result of the screw worm fly eradication, the deer population in vast ranching areas has greatly increased and new ranch management programs will have to be worked out. It also will be necessary to reorient certain management practices for instance, the dehorning of cattle and the castration of bulls can take place at other seasons than previously, and the methods adopted, for these operations can be changed because there is no longer the problem of fly strike.
During seasons of higher rainfall and humidity the incidence of internal and external parasitic infestation is high, and provision should be made for livestock to be protected against those hazards. Animals which lack adaptability become prey to parasites and also become more susceptible to diseases carried by insects such as ticks. Internal and external parasites can be partially overcome in two ways: the first method – which is preferable – is to breed cattle to be adapted animals with short hair, smooth coats and thick movable hides which are tick repellent. It would, however, be foolish not to use the protective measures science has provided in the form of various dips. De-worming remedies and therapeutic treatment of internal and external parasites can contribute greatly to overcoming those problems. If there are successful methods of combating disease by immunization or by therapeutic treatment, they should be employed, but these methods should not become the major issue in cattle breeding operations. They must be used only to overcome certain problems.
Rainfall and Humidity
Rainfall and humidity play a marked role in cattle production. In the hot humid areas of high rainfall, the soil pH usually is low as a result of the leaching out of soluble calcium, phosphorus and trace elements’. In such areas, small cattle usually are encountered. In humid, subtropical areas such as Southern Africa, India and Australia, the cattle are small because of the problem of maintaining thermal equilibrium. The problem of heat dissipation through evaporation of moisture from the lungs and the hide in a hot humid climate, becomes an acute problem. Animals maintained under these conditions usually have a relatively large skin area per unit weight. It is my opinion that in all regions where the relative humidity and temperature is high in those climatic zones where the average annual isotherm is about 65° F and the relative humidity is above 85 percent, the animals will be small. In many of those regions there is a very profuse plant growth and dense formation. In such areas it is desirable to maintain black cattle, as they are considered better adapted to dull and subdued light. In most areas where the humidity and temperature is high, the nutritive value of the pastures is very low as a result of fast pasture growth, the lignin content and hence the crude fiber content of such pastures is high and the protein content is low. In areas with a muggy climate the soil pH is low and nitrification cannot take place readily, hence, such areas must be fertilized with lime and if the soil. pH can be raised certain leguminous crops which will improve the protein content of the pastures can be grown. It must be realized, however, that under natural muggy conditions, livestock will be small. Soil fertility has an indirect effect on the welfare of livestock. As a result of the increased crop production on fertile soils, it is possible to improve the nutritional conditions of livestock; hence, better cattle can be produced on fertile land by virtue of greater yield crop which provides feed, of higher nutritional value.
No large cattle have been bred in acid soil country. This explains why the indigenous cattle of the high Himalayan Mountains are very small, the black cattle of the higher regions of Wales, the cattle on the higher slopes of the Drakenberg in South Africa and the indigenous cattle of Mashonaland are all small. Mashonaland is a highly fertile area but lacks lime, and as a result of the low pH in that region the cattle have small skeletal development. In areas where the soil pH is low, nitrification cannot take place successfully and hence the grasses grown in those areas have a very low protein value and do not form a natural curing hay on the land during winter. It is very interesting from an ecological point of view to have a thorough knowledge of the indigenous trees that grow in an area. The trees which grow in an area are indicative of the soil pH value and are correlated with nutritional value of the natural pasture.
In work done at the Mara Research Station in South Africa, cattle were kept on the same ranch in paddocks 3 miles apart under the same managerial conditions. The only difference in these pastures was that the one section had high soil pH as indicated by the Acacia tiortulis trees, and the other section had a low soil pH as indicated by the Combretum apiculatum trees growing there. Steers maintained in the two pastures differed 300 pounds in live weight between pastures at 3 years of age in favor of those on the high pH (6.5) pasture. In the low pH pasture the soil pH was approximately 4.5 to 5.
Every spoke of the wheel as drawn in the diagram has been discussed and it is very definite that if there is complete harmony between the animal and its total environment that the wheel will be round — the spokes will be equidistant from the hub and will not throw the wheel out of balance. If there is complete harmony between the animal and its total environment the animal will flourish and be an efficient producer. The wheel will move forward smoothly and progress will be made in the breeding of better livestock. A thorough knowledge of how each environmental factor influences the animal will enable us to select animals adapted to a particular environment. In successful livestock production it is essential that the breeder be well acquainted with the climatic conditions of the environment in which he intends to breed cattle. It is essential that a thorough knowledge of the interactions between plants and total environment, trees and pastures and pastures, and the livestock be understood. If we understand the particular hazards of an environment it will be possible to select those animals in that environment which are more adaptable and which will propagate adapted animals.
In livestock production, much stress is put on performance testing of the livestock. Hence, those animals which respond best to certain nutritional conditions are selected for further breeding purposes, but, if in a particular environment the nutritional conditions are fairly good but temperature becomes a hazard, more emphasis should be placed on the selection of cattle able to withstand high atmospheric temperatures. In mountainous areas radiation becomes a problem and more stress should be placed on selecting cattle which can overcome the hazards of ultraviolet radiation. By carefully evaluating the total environment production records and being aware of the limiting factors in the environment, it will be possible to breed well adapted cattle. Selection is our mightiest tool and the time has come that we must regionalize our livestock production on ecological grounds.
Red cattle and light-colored cattle with pigmented hides should be stocked in the open Savannah country, and in forested humid and muggy climates, cattle should be black. At high altitudes animals should have brown or black hides, A white colored hide lacking pigmentation is a great hazard to animals in high altitudes. In livestock breeding, it is essential to carefully observe animal behavior and to determine which factors in the total environment cause stress on the animal. By changing certain environmental conditions and by selecting cattle which are in harmony with their environment, livestock production can become efficient.
An important factor to be remembered in livestock production is that reproduction is the most sensitive index of the total adaptability of the animal. Any environmental factor which causes a stress on the animal will reduce its fertility. In the selection of cattle to be fed under artificial conditions, it will be necessary to select on the basis of performance testing in feed lots. To breed cattle that must be able to overcome high atmospheric temperatures, it will be necessary to select smooth coated cattle which become smooth coated early in spring. An animal with a poor nutritional status which comes through the winter with difficulty and has only a small reserve of vitamin A in the liver will not readily shed its coat. Even when daylight lengthens, it will not possess the vitamin A required to assist in shedding its winter coat. Furthermore, the animal which sheds its winter coat early is sexually more active and more fertile. Every heifer that sheds its hair the first spring after birth and becomes sleek coated will be a good one. No degenerate animal is able to do this and if one is not able to carry out all the adaptability tests, it is best to select the early hair shedders since they are the ones possessing nutritional reserves and hormonal balances enabling them to become smooth coated early in spring.
If intense light is a problem, as it often is in coastal regions and in open savannah country, it will be necessary to select animals which have light coat color and dark pigmentation in the hide. Animals exposed to intense ultraviolet radiation should preferably be dark colored, and if Hereford cattle are maintained at high altitude every effort should be made to breed these cattle to have pigment around the eyes. The problems of disease in any well managed herd should be overcome by preventive inoculation.
The third dimension or depth to the wheel is indicative of my approach to judging livestock for functional efficiency. I felt that it was necessary that one should judge cattle with an object of seeing more than the superficial. We should not only see the animal from the outside — it’s external appearance – but we must endeavor to interpret what we see in terms of the animal’s internal environment — in terms of its endocrinologic and physiological functions.
Successful livestock production and ranching depend on calving and weaning percentages. The aim in livestock production is to produce the maximum amount of beef per unit area. Every rancher can breed better cattle than he does at the present time and it is essential that this responsibility is appreciated. The rancher must realize that selection is his best tool. The institutions of higher education must devote much more attention to the teaching of livestock ecology. The relationship between the animal and its total environment should be more clearly understood. It is only through complete adaptability and selecting for functional efficiency, that is, regular reproduction and efficient food utilization, that a success can be made of livestock production.
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