Page 224 - The Welfare of Cattle

ranGe beef CoW and CaLf heaLth and WeLfare 201

Ocular Squamous Cell Carcinoma). This occurs mostly in cattle with white skin around the eyes,
and therefore tends to occur in some breeds more than others, but it is also promoted by extreme
sun exposure. Caught early, the cancer can be treated and eliminated. In prolonged or severe cases,
it can spread to other body regions and may warrant euthanasia. Eye problems account for about
1%–2% of cows that are culled.
The extensive management and feeding of beef cattle presents other challenges. Although
these are not common, they can affect large numbers of animals in a herd, or even the entire herd.
Such problems include plant poisonings and nutrient deficiencies. There are a wide variety of toxic
plants. Some affect the cardiorespiratory system, such as larkspur poisoning. Others affect kidneys
(oxalates), neurologic system (locoweed), liver (senecio species, kochia weed), or skin (kochia
weed, buckwheat). Some plants that are commonly eaten and nutritious can become poisonous in
certain environmental conditions such as drought or too much moisture, including nitrate poison-
ing, cyanide poisoning, bluegreen algae poisoning, and fungal endophytes on some grass species
(ryegrass poisoning, fescue grass). These problems may lead to severe animal health issues and
even kill some animals. Surveys estimate that about 1%–2% of all cattle deaths are attributable to
poisoning.
Nutrient imbalances also can affect large numbers of animals. Common hazards for range cattle
include copper deficiency, hypomagnasemic tetany, sulfate toxicity, selenium poisoning, selenium
deficiency, and others. These are usually specific to particular types of soils or particular plants
that grow on the soil. Cow/calf producers and their veterinarians or nutrition advisors try to prevent
these problems by sampling the feed or sampling the animals and then feeding supplements to try
and balance the ration. But it remains a liability of extensive animal management that the entire diet
is difficult to control. Cows on range are obliged to eat the forage that is available. Sometimes defi-
ciencies and excesses can be identified and avoided, but commonly the problem is already occurring
before it can be identified. Of the 1% of cows that die on the ranch, about 2% of these deaths are
attributed to such mineral/metabolic diseases.
Another hazard for beef cattle is the grazing of plants that have spines, seeds, or awns that injure
the lining of the mouth. The initial injury is usually minor, but commonly the injury is then invaded
by bacteria that cause inflammation of the oral cavity, or that spread through adjacent tissues and
the lymphatic system to cause severe cellulitis or abscessation. Since the problem occurs around the
mouth and jaws, it is commonly referred to as lumpy jaw. In some cases, the problem can be treated
and resolves, but in severe cases the animal may be culled or die.
Perhaps the most important occupational hazard of beef cows, and particularly first-calving
beef heifers is difficult calving, called dystocia. If the calf is too large for the size of the maternal
pelvis, or if the calf is presented for birth in an abnormal position, or in the case of twin birth, the
dam may have trouble delivering, or the delivery may be impossible. This presents a life-threatening
problem for the calf, and will be discussed below, but also a major problem for the dam. One of the
reasons that having a defined short calving season is preferred by most ranchers is that it facilitates
gathering the dams for a discreet number of weeks to monitor delivery and assist when problems
occur. The majority of difficult births can be successfully assisted if the difficulty is identified, and
alternatively a caesarean section surgery can be performed. This requires more-or-less round the
clock monitoring and calving season is the busiest time of year for ranch managers.
Dystocia is more common in 2-year-old dams, because they have never delivered before and are
not fully grown to mature cow size. This problem can be a major source of animal injury including
torn tissues and crippling neurologic or musculoskeletal injuries. Bulls can be selected to produce
smaller calves at birth, called “calving ease sires,” and many ranchers focus on this feature when
they select breeding bulls for their heifer breeding. Dystocia is a fact of life in any population
and cannot be completely eliminated. But over the last several decades, with better bull selection
procedures, increased focus on heifer selection and growth, and better education about both pre-
vention and resolution of the problem the problem now occurs in only 2%–3% of mature cows and