HEALTH-MANAGEMENT INTERACTION: BEEF CATTLE

Maxs U.E. Sanam

HEALTH-MANAGEMENT INTERACTION: BEEF CATTLE

BEEF CATTLE BREEDING HERDS BEEF FEEDLOTS

Several managerial practices increase productivity within cow-calf herds when they can be implemented economically and practically. A restricted breeding season Identification of the optimal calving season A good heifer replacement program Heifer reproductive tract scoring, Proper nutrition Good herd health Bull breeding soundness examinations Cross-breeding Maintaining good records

Reproduction In most regions of the world, there is an

optimal period for the females to calve, suckle, and rebreed.

This period is mostly related to nutritional opportunity, although other environmental factors such as cold or heat strees and parasite population may play a role

Benefits of restricted breeding seasons (65-80 hari)

Pregnancy Testing The longterm goal is to develop a beef herd of

uniform, low maintenance cows that thrive in their given environment

This goal is strenthened by having a restricted breeding season in which open cows are culled from the herd

Cows should be sorted by projected calving date and body condition score (BCS)

The herd pregnancy diagnosis (HPD) represents an important starting point for beef herd diagnostics and advice and is a pivotal component for informed decision making

Breeding Soundness Evaluation Reproductive performance is influenced by

many factors including sire fertility, heard health aspects, and opportunity to mate

BSE is a technique for assessing the reproductive performance of the cow herd

It includes obtaining relevant information, analysis and interpretation, and recommendation for improvement

One measure of reproductive performance is the number of exposed females that actually raise a live calf

Other valuable information may be obtained from an analysis of the distribution of of pregnancies (and calvings) that resulted from a particular breeding season

This distribution may be studied on the basis of timing (eg, 21-day estrus periods), breeding groups, female age or parity, nutritional opportunity (eg, BCS) etc.

Such analysis provide the basis for evaluation of either the breeding or calving season

A successful breeding soundness evaluation for a bull is also very important.

Because reproductive performance is an improtant economic trait in the cow herd, the reproductive capabilites of breeding bulls assume great importance.

The best assurance that a bull is likely to be fertile is a successful breeding soundness evaluation

A rule of thumb for bulls is that they can breed ~1 cow/mo of age in a breeding season of 65 - 80 days

For example, a 38-mo-old bull that passes his BSE should be able to breed 38 cows in 65-80 days

This rule is effective for bulls about 14 – 50 mo old, with 50 cows/bull being the maximum

Cull Cow Selection and Manegement

Culling of cattle in a beef operations usually implies removing those that cannot meet or maintain performance and economic criteria for the herd

Other reasons may include physical or temperament problems in animals, as well as judicious culling during periods of environmental hardship or economic necessity

The judicious removal of nonperforming females is also important in maintaining or improving herd fertility

However, the assumption that cull cows are necessarily unproductive may not always be correct; recent surveys indicate that ~43% of cull cows in the USA are pregnant

In addition, “open” females are not necessarily infertile

Identification of appropriate candidates for culling is critical and should be an important component of pregnancy testing

Benefits of restricted breeding seasons (65-80 days) include:Enhanced production potentialFavorable environmental factorsA concentrated calving season and more

homogenous calf crop Increased opportunity to perform

prebreeding management procedures and monitor nutrition

Improved female replacement and culling procedures

The ability to detect problems early

Nutritional management Nutrition is the most important limiting factor

of beef herd reproductive performance. Increasing stocking rate tends to cause

increased gain per unit land area (pasture) but can result in decreased gain per animal

The key is to have these two factors in balance so that pasture land is optimally grazed and gain per animal is adequate

Overgrazed pasture is detrimental to the environment and can severely reduce gain per animal

Nutritional requirement vary throughout the year The most critical periods for reproduction are

immediately precalving, when fetal growth is maximal along with lactation prpeparation, and early postcalving, when maximal lactation is combined with the need for rebreeding

Environmental conditions can strongly influence the nutritional requirements and intake of cattle

For example, cold weather increases energy needs, whereas hot or inclement weather can reduce foraging opportunity

The quality and quantity of range forage varies greatly throughout the year and between years, influenced by moisture, soil fertility, plant species, and grazing pressure

Seasonal changes in the nutrient density of rangeland forages are mainly associated with the degree of plant maturity.

In general, the greatest nutritional value of plants develops before maturity

Good nutritional management involves matching, as far as possible, the nutrient requirements of cows and nutrient density of the pasture by careful consideration of factors such as

the types of animals involved, stocking rates, plant species available, season of grazing, fertilization, and grazing method used

Body Condition Score Accurate and timely determination of

nutritional status of grazing animals represents a challenge for beef producers

The use of BCS is an effective indirect method for determining nutritional status in breeding females

BCS and changes in BCS, appear to be more reliable indicators of nutritional status than is body weight or change in body weight, which can vary with gut fill and pregnancy status.

BCS can be assessed more convenient than body weight

BCS varies throughout the year and should be monitored regularly

In the 1-9 BCS system widely used in North America, the reference standard for beef female is a BCS of 5, which represents an average, moderatele fleshed cow that is neither fat nor thin

In general, cows should calve when they are are between BCS 5-6 (heifers at 6-7) and then regain the weight lost at calving or gain slighly until breeding.

It generally takes around 2 months to gain 1 score (75-100 lb or 34.1 – 45.5 kg) under pasture conditions.

The ideal time to assign BCS to cows is 2-3 months precalving.

This gives ample time to move cows to an optimal precalving BCS, because BCS at calving is higly correlated to herd fertility

It is best if someone other than the owner (eg, veterinarian, extension specialist etc) does the BCS evaluation of the herd

HEALTH AND PRODUCTION MANAGEMENT PROGRAM A cost effective herd health and production

management program is essential for the economic viability of cow-calf operations.

A good herd health program manages risk of disease and lowered productivity at a number of levels, including considerations of biosecurity, nutrition, and the judicious use of biologics and parasiticides

One starting point for such a program is to identify current production losses by comparing the performance of the particular herd with relevant standards, from regional or national surveys, which can also provide an economic estimate of losess.

The major disease risks for a given herd, along with appropriate preventive measures, should be established in consultation with herd owners

The best times for herd intervention must be identified. These often coincide with other managerial tasks and can be syncronized to minimize herd disruption and labor costs.

One approach is to devise a herd-health “calender” in which the health events are coordinated with major operational events

Interventions for a particular herd vary based on factors such as available labor, normal herd working dates, calf weaning dates, calf management practices, and previous disease problems

Vaccinations Prebreeding vaccination should be

completed ~4 wk before the start of breeding and should be based on local patterns of disease and any state or national requirements

Replacement females should be vaccinated with the same vaccines given to mature females before breeding

Precalving vaccinations are intended to protect the newborn calf throuh colostral transfer (eg, protection against neonatal calf diarrhea)

Preweaning is an important intervention that can help prepare calves for the stress of weaning and reduce the possibility that such stress will compromise the efficacy of biologicals (eg, vaccines)

Common vaccinations include the clostridials and bovine respiratory diseases.

A broad-spectrum anthelmintic should also be given at this time, because calves that have been on pasture have almost certainly been exposed to internal parasites.

For areas where brucellosis is under regulatory control, appropriate heifer vaccination shoul be done within the age ranges stipulated

Bulls should receive the same vaccination as the cow-calf herd, with some exceptions.

Buls should not be vaccinated for brucellosis. Also, the trichomoniasis vaccine currently approved for use in the USA is not approved for bulls.

Caution! Bulls vaccinated with MLV infectious bovine rhinotracheitis may recrudesce this virus and shed it in the semen.