by: Daniel Kniffen
Assistant Professor of Animal Science Penn State University
Many times a producer does not consider or appreciate the value of a good year-round herd health program until confronted with a difficult calving season or an unacceptable level of calf loss from health challenges.
Year-Round Herd Health
Managing through a disease outbreak in a herd is significantly more costly than implementing a preventative health program. Understanding that many cow calf producers have employment away from the farm or ranch greatly reduces the amount of time available during the day to attend to management and health issues with the cow herd.
As a producer it is important to take an active role identifying health related issues particular to your area. Consulting with other producers in your area both beef and dairy are a good initial resource for not only someone new to the cattle business but also for individuals that have move and are new to an area. Your local veterinarian is also an excellent resource to help develop a herd health program.
During their life cattle develop two types of immunity passive immunity and active immunity. Passive immunity is immunity that passes from the cow to her calf in colostrum. Active immunity is either naturally developed from exposure to a disease or as the result of an immunization program.
Additionally in the initial development of a herd health program it is good to establish a plan to meet the management needs of the herd. It is important to remember cattle need to be most protected as they enter times of stress or when their health will be challenged. Many times periods of stress are elevated when a change occurs in the weather or the management of animals. For example, stress occurs when calves are weaned or again when they are co-mingled with other animals. Calves will remain healthy as long as their level of protection or immunity is higher than the level of stress they are exposed to.
A good herd health program should begin in the cow herd prior to the calves being born. A cow herd vaccination program stimulates the immune system in the cow causing her to build the necessary antibodies to provide passive immunity to her calf in colostrum. This is the first line of protection for the new calf. It is important to remember several factors beyond a health program will impact the health and vitality of the new calf. For example changes in the body condition score of the cow will have a direct impact on the quantity and quality of the colostrum a cow produces. The industry established a body condition score of 5 - 6 is an optimum range for cow performance pre-calving. Cows in a lower body condition will not produce the same quantity or quality of colostrum. Calves born to these lower body condition cows will not receive the same level of protection as calves born to cows in a higher body condition score.
In addition to preparing the cow for calving it is important to establish a good health plan for the calves prior to being moved from the farm or ranch of origin. Calves will carry a level of natural immunity to the health challenges and diseases it will be exposed to where it is born. A good plan should also consider the future location of a calf if it is sold from the premises. So plan not only for where the calf currently resides but also build a vaccination plan for where the cattle are being shipped to if sold.
The following chart outlines the suggested times during the year and principal products to consider in a basic year round herd health program for the North East. No specific product names are identified. Producers can source products from numerous suppliers and should consult with a local veterinarian for the specific products available. Additionally, there are some specific products that should be included in a vaccination program for calves being shipped out of state to different parts of the country.
Year Round Herd Health Program for the Cow / Calf Herd
Cows 45 - 60d pre-calving vaccinations
� Killed Virus complex (IBR BVD P13 BRSV)
� Clostridial complex
� Tetanus Toxoid
� Consider adding a pinkeye vaccine at this time
All open Cows 30d prior to breeding:
� A Modified Live virus complex (IBR BVD P13 BRSV)
� Clostridial complex (only required for the new breeding age heifers)
Calves at time of vaccinating open cows Above Optional
� A Clostridial Complex consider including pinkeye vaccine
� Calves could be boostered with a second round of vaccine three to four weeks following this first round of vaccination
Calves 45d prior to weaning
� A Modified Live virus complex (IBR BVD P13 BRSV)
� A Clostridial complex (consider including pinkeye)
� A Pasturella vaccine
� Tetanus Toxoid
ALL calves should be re-vaccinated (Boostered) 14 - 21d following the initial vaccinations itemized above. This will improve the level of protection developed by the calves.
Wean 30d following the last round of vaccinations. Expose calves to feed bunks and water tanks or automatic waters. Calves should be weaned a minimum of 30d prior to shipping.
Producers should always follow label directions for dosage and route of administration when working with food animal health products. Strict adherence to product label and withdrawal times must be practiced at all times. Producers should participate in and become certified in Beef Quality Assurance (BQA) training and employ good BQA practices when vaccinating and handling animals. Many times neighbors will help neighbors when working larger groups of animals. Particular attention should be paid to farm/ranch Bio-security as people enter and exit the premises. This includes people either coming over to help or entering the premises as visitors and potential customers.
Internal Parasites
Internal parasite control in cattle is location specific and actually varies from herd to herd. Many times if the cow herd is managed in a rotational grazing program, on a sufficiently large enough area to avoid crowding and having a sufficiently long enough interval (24d) between repeat grazing periods on the same area, the herd may not require an intense parasite control program.
The most accurate method to determine the parasite load of the cow herd and the necessity to implement a de-worming program is through the use of a fecal egg count. This method will accurately determine the number of parasite eggs being shed in the manure from the cows. With optimum environmental conditions - moisture and warm temperatures - the eggs develop into infective larvae in two weeks or less, and move from the fecal pats onto surrounding vegetation. The larvae migrate up the grass leaves to the upper 2/3 of the leaf. As the grass is consumed by the cattle they also ingest the waiting larvae. It is through this cycle animals in the herd become infected. Once ingested, larvae develop to mature egg-laying adults in three to six weeks and the cycle starts over again.
If de-worming is necessary or recommended it should occur approximately 6 weeks into the grazing season. A broad spectrum product should be used that kills the majority of adult and larval nematodes, as well as inhibited larvae. This system will be most economical as it will be effective on a wide range of the parasite life cycle. If the decision is made to only de-worm the cow herd one time per year, consider the fall as cows come off grass. De-worming at this time will kill any parasites picked up during the summer grazing season. This method will allow the cows to get through winter without the physical stress of worms. As an additional benefit it will also prevent egg shedding for the first part of the next grazing season.
There are several important facts to consider when selecting an anthelmintic. Delivery method is very important. A producer must select a product which fits into their particular management style.
Next the spectrum of parasite control. Different products will control different types of parasites. Make sure to choose a product that is effective on the parasites of the region.
Duration of activity, some products are longer acting as compared to other products. Also there will be a price consideration. Choose the most cost effective product not the cheapest product. Don't be penny wise and pound foolish.
External Parasites
The short list of external parasites which can affect cattle include lice, warbles (grubs) and flies. Lice are most prevalent in late winter. Lice can be a problem on all sizes/ages of animals. Generally if they are identified on one size group most probably they are affecting all animals. The telltale signs of lice include; continuous severe itching and hair loss, primarily around the neck, shoulders and over the tail head. Because the louse spends their entire life cycle living on an animal, development of a control program is significantly easier.
There are three separate stages in the life cycle of lice:
1. nit (egg)
2. larva
3. adult
All available products kill lice in both the larvae and adult stages. Unfortunately no products kill the nit. To completely eradicate lice from a herd, the cattle must be treated two times. The same product may be used but the application must be done two weeks apart. Alternatively, the cattle can be treated with a product that has more than two weeks of persistent activity. There are numerous commercial products available that are approved for use on cattle. Some products will control more than one parasite. Shop for the most competitive price based on the needs of the particular cow herd. Lice problems will typically clear up as the ambient temperature rises in late spring and early summer. However they can still cause decreases in body condition and milk production if the infestation is severe enough.
Flies
Fly control for the cow herd can be achieved through selection from a variety of different management tools. Some of the more common methods are outlined below.
Fly Tags
Fly tags are similar in style and application method to an identification ear tag. Many commercially available fly tags have an effective life of three to six months depending on the tag and the product it contains. Tags may contain either pyrethrins or organophosphate compounds or a combination of both products. Fly tags are very popular with producers because of their ease of application and length of effectiveness. Producers should remove fly tags from previous years and reuse the same hole in the ear of the cattle to preserve the integrity of the ear.
Pour-ons
Pour-on insecticides are a popular method of parasite/insecticide control. Topically applied, pour on products many times provide convenience and ease of application when combined with other management processes requiring cattle be handled through a chute. Many will provide protection from multiple types of parasites. Pour-on products have numerous different formulations. These products typically provide protection from known resistant fly populations for 2-11 weeks of the year. As stated earlier one distraction to using pour-on, cattle must be processed through a facility to allow direct application to each individual animal.
Back Rubs
Back Rubs generally are constructed of an absorbent type material that will retain a volume of liquid. Back rubs have been constructed from large diameter cotton rope or absorbent fiber material packed inside a large sock type tube. The back rub will be hung between two posts, elevated off the ground high enough so the cattle can stand under the rub and it will lie over their back. As cattle rub their back with the rope they will be coated with the insecticide contained in or on the rub. Many times the concentrates consist of either a pyrethrins or an organophosphate. These concentrate products are generally mixed with fuel oil as an extender and applied to the back rub to later be transferred to the cattle utilizing the device. To be utilized effectively back rubs should be erected in a high traffic area where cattle pass on a regular basis to ensure treatment application.
An inexpensive option in smaller cow herds is to apply insecticides using a Hand Sprayer. Concentrates can be mixed on an as needed basis in a sprayer and applied to cattle two to four times a month. Try not to apply spray immediately before a rain storm. This may reduce the effective time of the treatment.
Other options exist as a means to get insecticides applied to cattle. This is just a partial listing that provides some of the more common methods in use today.
Flies can develop resistance to products that contain pyrethrins and those containing organophosphates; rotation between these two types of insecticides on an annual basis is thought to reduce the likelihood of resistance occurring.
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