Conditioning Principles for Performance Horses

Posted in Horses with tags , , on January 6, 2012 by extensionlivestock

As the weather gets colder, some horse owners are gearing up for early spring riding activities and competitions, while others are getting ready to give their horses some time off after a busy summer and fall.  Whichever category you fall into, there are scientific conditioning principals for preparing horses for events, as well as for keeping horses moderately fit during time off.  An important concept that one must understand in order to properly condition a horse is what exercise physiologists refer to as metabolic specificity, which basically means that the conditioning program must be comparable to the event or competition the horse is training for; the conditioning program must be designed specifically for the activity the horse will be asked to do.

Horses will often experience some level of fatigue during performance.  The objective of a fitness program is to condition the horse in a way that delays the onset of acute fatigue, which is when injuries are more likely to occur.  In order to design an effective and safe program, several factors need to be considered such as the age of the horse, its body condition, what previous conditioning has been done, and whether the horse is recovering from an injury or illness.   Very young horses and horses that are very unfit or haven’t had much prior conditioning will most likely need 3 to 6 months of targeted fitness work, or more, depending on the type of event they are training for.

Initial conditioning should begin with a planned goal in mind and should be started early enough to avoid forcing fitness development into a short period of time.  The fitness program should begin with long, slow distance work that targets aerobic exercises.  These exercises are categorized as aerobic because the heart rate will generally stay below about 150 beats per minute (bpm).  The goal is to elevate the horse’s heart rate and keep it there for several minutes, while over-time, gradually increasing the distance the horse travels.  Exercises will consist of walking and trotting intervals in the beginning, with increasing trotting and slow canter work.  Two to three aerobic training sessions per week, alternated with specific skill training sessions, should be done for several weeks up to several months before beginning advanced stages of fitness development.  Spending enough time in early conditioning to properly prepare the horse for higher intensity work is critical, and the amount of time it takes will depend on the starting fitness level of each individual horse. 

During this time, pre-ride checks should be used to evaluate how the horse is responding to exercise.  Taking a resting heart rate, observing the horse at the walk and trot, and checking specific areas for sensitivity will help you determine how to proceed with conditioning.  A resting heart rate can be taken by using the fingers to palpate the facial artery under the skin in the area of the horse’s lower jaw.  It is a good idea to determine what a normal resting heart rate is for your horse before beginning a new exercise program.  An elevated resting heart rate is a signal that the horse is experiencing some level of discomfort due to pain, stress, or illness.  Another part of the pre-ride check is observing the horse at the walk and trot for stiffness or lameness.  Check the back and loin for soreness by placing the thumb and forefinger on either side of the withers and, applying gentle pressure, move down the back, loin, and croup.  Horses will express soreness by dropping down away from the pressure. It is normal for horses to exhibit loin soreness during a new conditioning program, but regular checks will help determine when a horse needs a rest and when and how to continue as the muscles get stronger.  If the pre-ride check reveals that the horse is experiencing discomfort, exercise should be approached in moderation or the horse should be allowed a day-off with access to free exercise in a paddock.

Once the horse is responding positively to gradually increasing levels of aerobic exercise, the more demanding exercises can slowly be introduced.  Advanced fitness development introduces high-intensity, short duration work.  These types of exercises will generally increase heart rate to well above 150 bpm and are considered to be anaerobic as the muscles are now working too hard or too fast to rely solely on oxygen in the process of burning fuel.  During this time, horses are more at risk for energy depletion and fatigue, and thus injury.  The most effective anaerobic conditioning programs are those that are specific and are increased in a gradual overload fashion, which is also called interval training.  Interval training consists of multiple bouts of high-intensity work (galloping, cutting and hard-turning a cow, jumping a course, stopping and rope work) interspersed with relief intervals during which at least partial recovery of heart rate and respiration rate is allowed.  This method of anaerobic conditioning allows more work to be done while bringing on fatigue gradually and in a controlled manner; however, this type of training should be done sparingly and one to two days per week will be sufficient.  To begin an interval training program, a high-intensity exercise is done for several minutes followed by walking until heart rate and respiratory rate return to close to baseline levels.  Then the high-intensity activity is repeated, followed again by a recovery period.  It will be important to monitor how quickly heart rate and respiration rate recover as well as how low the heart rate falls during a specified recovery time.  If the heart rate has not returned below 100 bpm after 5 minutes of recovery, it is time to quit for the day.  As the horse becomes more fit, the high-intensity exercise can gradually be done for longer periods of time, and/or the number of repetitions can be increased until the end goal is achieved.  During advanced fitness development, it will also be important to continue with some days of long, slow distance work, making sure to offer one or two days of free paddock exercise per week as well.

Conditioning of performance horses is influenced by a variety of factors, and individuals will differ in their ability, behavior, and strength.  Allowing ample time to achieve fitness development and closely monitoring horses during a fitness program will be critical to success.

Reproduction Reproduced…..Part 1….

Posted in Cattle on November 28, 2011 by extensionlivestock

This article is intended to be Part 1 of a two-part series on the reproductive system in cattle.

As we dive head first into winter, a lot of area operations are beginning to look forward to the next “big thing” – breeding season.  If we are looking to have fall calves in the area, we are generally concerned with the time frame of February, March, and April as the time to turn the bull out and start preparing for a new calf crop.  However, before we start, it may be of interest and importance for us to take a look at just how effective we can be.

In general, a cow’s reproductive system is not terribly unlike that of the human – and no, I’m not making a snide comment about anyone under my breath.  Cattle have the same physiology and basic processes that humans do when it comes to this topic.  A cow’s estrus cycle is 21 days; her gestation period is roughly 283 days (give or take 3 days in either direction for differing breeds) or 9 ½ months.  We expect our animals to work for us, but we must be aware of the inner workings of the reproductive process before we can fully understand how to help, or what options we choose.

To begin, we need to know what we’re dealing with, and how it functions.  We’ll start with the hormones produced by cattle during the estrus cycle.

  • Progesterone – produced by the corpus luteum (yellow body or “CL”) is a hormonal cell derived from the wall of a follicle post-ovulation.  Progesterone is a naturally occurring steroid hormone that prevents estrus and prepares the uterus for pregnancy.  Large luteal cells are killed by lutelolytic prostaglandins.
    • Common names/products:  CIDR (vaginal implant), MGA (feed additive)
  • Estrogens – produced by a dominant ovarian follicle, the primary ovarian steroid is estradiol 17-beta.  Estradiol acts on the hypothalamus to induce estrus behavior in the absence of progesterone.  The estradiol produced by the follicle inhibits follicle-stimulating hormone (FSH).  When a follicle produces estradiol in absence of progesterone, it induces a surge of the gonadotropin luteinizing hormone (LH) at the onset of estrus.  Estradiol can also stimulate endometrial cells to produce prostaglandin F2-alpha (PGF2a).
    • Common names/products:  GnRH (shot), Factrel (shot), Cystorellin (shot)
  • Prostaglandin – normally produced by the endometrium of the uterus and carried by the uterine veins to ovarian artery.  The primary function of this hormone is to kill luteal cells, and it may activate uterine neutrophil to kill bacteria.
    • Common names/products:  Lutalyse (shot)

Now that we have a rudimentary understanding of the hormones involved in the estrus cycle, we will begin to look at the phases of estrus.  There are four basic stages of the bovine estrus cycle: proestrus, estrus, metestrus, and diestrus.  It is important to note that Day 0 is considered estrus, Days 1-5 are metestrus, Days 6-17 are diestrus, and Days 18-20 are proestrus.

  • Proestrus – occurring during the late luteal phase, if a pregnancy is not recognized in the system by day 17-18, prostaglandin is released.  This causes luteal regression (progesterone declines) and GnRH levels rise, causing LH and FSH to be produced.  Once this occurs, a dominant follicle will establish itself and continue growing – producing estrogen in the granulosa cells.  Estrogen is what actually causes the signs of estrus in the animal.
  • Estrus – during this period, the FSH and estrogen are declining in the animal’s system.  The LH peaks during standing estrus (standing heat), and will last approximately 18-20 hours.  Note:  this time may be shorter due to heat stress during the summer in this area of the country.  After this time period, cells start producing progesterone, which inhibits both LH and FSH release.  Ovulation occurs 12-18 hours after end of estrus.
  • Metestrus – this stage is 3-5 days long and is the time of luteal development.  The corpus hemorrhagicum (CH) is the “bloody body” that is left behind after ovulation occurs for the dominant follicle.  The CH begins to develop into a corpus luteum at this point; however, the CL is not mature at this stage, so progesterone is still rising.  Without the CL being mature, no prostaglandin receptors are present, making luteolysis via prostaglandin impossible.  Basically, this means we cannot regress the CL by means of lutalyse or other drugs.
  • Diestrus – lasting from days 5-17 of the estrous cycle, this is the time that the mature CL is producing progesterone.  During this time, there are 2, 3, or 4 waves of follicular growth depending on the individual cow (follicular waves).  This means that follicles form, last for about 2 days, then regress.  In understanding synchronization programs, this is a very important piece of the puzzle to understanding a cow’s response to the program being used.  In 2 wave cows, wave one starts on day 2, wave 2 starts on day 11 and it is the second wave that ovulates.  On 3 wave cows, wave 1 starts on day 2, becomes static on days 8-12 and regresses on days 12-16; wave 2 starts day 9, ends day 17; and then wave 3 starts day 16 and eventually ovulates.  At the end of diestrus, if the CL recognizes no pregnancy, the luteolytic hormones are produced and the CL regresses.

During Part 2 of this article, we will look into synchronization programs for both herd bulls and artificial insemination uses.

Body Weight Estimation in Horses

Posted in Horses on November 7, 2011 by extensionlivestock

Being able to estimate body weight is useful in many different management scenarios.  First, safe and effective feeding of horses should be done according to body weight.  Additionally, many medications such as dewormers require an adequate estimate of body weight in order to avoid the danger and waste of overdosing, or the ineffectiveness of under-dosing.  Unfortunately, most horse farms do not have easy access to livestock scales.  Research has shown that when using visual appraisal alone, the majority of horse owners underestimate their horse’s weight by at least 150 pounds.  There are two commonly used methods of estimating body weights in horses: 1) commercially available weight tapes that use only a heart girth measurement and 2) weight estimation formulas that use both a heartgirth and a body length measurement.  Although commercially available weight tapes may be the most commonly used, they have been shown in several studies to be the most inaccurate.  The weight estimation formula is a more reliable method for estimating body weight compared to both visual observation and commercial heartgirth weight conversion tapes.  The weight estimation formula uses heartgirth circumference and a body length measurement, both measured in inches, along with an adjustment factor.  The equation is:

(Heartgirth x Heartgirth x Body Length) / 330  = Body Weight

Measurements should be taken in inches with a plastic measuring tape that is at least 75 inches long, although longer tapes will be needed for larger breeds of horses.  Cloth tapes should not be used as they can stretch giving inaccurate measurements.  The heartgirth measurement should be taken by running the measuring tape around the circumference of the horse, directly behind the shoulder, crossing over the highest point of the withers, while keeping the tape perpendicular to the ground.  Before taking the body length measurement, the horse should be stood square and on level ground.  The length measurement is taken from the point of the horse’s shoulder, straight along the horse’s side and around the corner of the hip to the point of the buttock.  The point of the buttock is half way between the widest part of the stifle and the tail.  It will take two people to take the body length measurement.  When using the formula to estimate body weight in weanling horses, the denominator should be changed from 330 to 280.

Studies conducted on hundreds of horses have shown the weight estimation formula to be the best method to estimate actual scale weight and although it will not be exact in all horses, it generally averages within 25 pounds of actual weight.  Estimations will be more inaccurate in horses that are not as well balanced, particularly horses that are extremely heavy fronted and light hipped, and may be off by as much as 150 pounds.  Additionally, estimations will not be as accurate in horses that are severely underweight (BCS less than 4) or overweight.  Still, if scales are not available, the formula method will be a better estimation than commercial weight tapes or guessing.

 A second source of inaccuracy with this method of weight estimation is human error.  For owners who are learning to take measurements for the first time, it is a good idea to get an actual scale weight on one or two horses and then practice taking measurements to learn the proper placement of the measuring tape.  Practice taking measurements as soon as possible after obtaining a scale weight, before the horse has had time for a large drink of water or a meal.  Again, always make sure the horse is standing square and on level ground.  Furthermore, if measurements are being taken on a horse to observe weight changes over time, these should be done at the same time of day, preferably in the morning prior to feeding.

Although it will not always be an exact estimation of actual weight, the weight estimation formula can be used effectively for most horses and will be a more reliable method than commercial heartgirth conversion tapes.  Overall, this simple tool can be used by horse owners to better manage their animals.

Placement of measuring tape for heartgirth and body length measurements.

Git along little dogies…….

Posted in Cattle on October 24, 2011 by extensionlivestock

Join us for a livestock field day!!

2011 Livestock Field Day (click me)

Udderly Intensive…….

Posted in Cattle on October 12, 2011 by extensionlivestock

Mastitis is a very complex subject to understand, and it is the most expensive disease in the dairy industry today. It occurs when an udder becomes infected by bacteria, which results in high somatic cell counts, reduction in milk production, undesirable milk quality – and ultimately, financial losses.

You, your family and your employees are invited to attend an Udder Dissection Wet Lab & Mastitis Workshop to learn about udder health and physiology. Stacey Homan and Marco Lopez, Vi-CORÒ Milk to the MAXÒ  Customer Support Specialist, will present and lead us through this training session in both English & Spanish.

 

A portion of the meeting will be held at the Pleasant Union United Methodist Church, 5929 Coble Church Road and then we will travel to and meet outside at the Bowman Dairy, 6506 Bowman Dairy Road to discuss cow comfort and their new bedded pack housing for the milking herd.

 

So that we can prepare accordingly for our sponsored lunch, please RSVP by October 31st by e-mailing extension.programs@chathamnc.org with Udder Dissection as the subject line and your name and the number of people coming from your farm in the body of the message.  If you do not have access to e-mail, you can phone in to the Chatham County Extension office at 919.542.8202 to RSVP.

 

Hope to see you November 3rd!

The Great Hay Debate

Posted in Horses with tags , , , , on September 26, 2011 by extensionlivestock

The digestive system of the horse is designed to utilize forages as the primary component of their diet.  No matter what they are used for, all horses need plenty of high quality forage, and feeding programs should be based around the forages that are available to the horse – not the other way around.  Horses require a minimum of 1% of their body weight per day in fresh pasture or long-stem roughage in order to avoid digestive disorder.  As natural forage eaters, most classes of mature horses can meet their daily energy requirements with forage alone.  However, an important point that horse owners must keep in mind is that horses can be nutritionally deficient and can also be subject to digestive disorders such as gastric ulcers even when plenty of forage is available to them, if that forage is not of adequate quality.

There are more myths associated with feeding horses than with any other livestock species, mostly spread by owners and other industry professionals that have very little basic animal nutrition training.  In my travels around the country I have heard a great deal of myths about which types of hay are best, or worst, for horses.  In some parts of the country it is believed that high-quality hays that contain a small amount of legumes will inevitably cause digestive upset, while in other parts many believe that the grass hays that are abundant in the southern United States are bad for horses.  The truth is that the quality of the hay in question is much more important than what type of grass it is.  It is more likely that digestive upset that is associated with feeding hay is caused by poor quality hays or by changing types of hay too quickly.  Just as with changing a horse’s feed, changing the type of hay in a horse’s diet should be done gradually over a period of several weeks in order to acclimate the gastrointestinal tract to the change in nutrients and the physical properties of the new hay.

There is no one forage species that is best for all classes of horses and owners must take into consideration the physiological status (age, metabolism, weight, health) of their horses as well as the level of activity and stage of production (growth, reproduction, lactation) when choosing hay.  In general, we classify hays in two different ways: grasses vs. legumes, and cool season grasses vs. warm season grasses.  There will be more pronounced nutritional differences between the classifications, but when comparing different grass species within a classification, nutrient make-up of the hay will have much more to do with the way the grass was managed than the species of the grass. 

In general, legume hays have more digestible nutrients and will be higher in crude protein, digestible energy, and calcium when compared to grass hays.  However, because of the unique digestive system of the horse as well as the actual amino acids that comprise the proteins in the hay, the biggest actual nutrient difference will be in digestible energy.  This difference explains the added weight gain or “bloom” many owners see when switching from grass hays to legume hays.  However, the fiber component of grass hays is typically more digestible than the fiber component in legume hays.  This is the reason that grass/legume mixed hays are generally touted to be the perfect hay for horses.

Due to the environmental conditions in which they grow, warm season grasses tend to be lower in overall nutritional value because of a decrease in the leaf to stem ratio.  In general, warm season grasses will be lower in crude protein, digestible energy, and minerals compared to cool season grasses, but they will be higher in fiber content.  Cool season grasses are also generally higher in non-structural carbohydrates (starches and sugars) which are a concern in the diets of horses with metabolic diseases or certain medical conditions. 

Most horse owners have heard over and over again that you can’t really predict nutrient content of a load of hay by visual appraisal alone, but you cannot predict nutritional value by knowing the species of grass either.  If management practices are kept similar, and the hays are of moderate to good quality, these nutrient differences between the classes of hays should hold true.  However, the nutrient content and quality of hay will be greatly influenced by how it was managed.  Nutrient content will be affected by the type of soil it was grown in, the fertility of the soil, how mature the grass was when it was cut, the % moisture at baling, the length of time it was cured, the quality and duration of storage, and even the time of day it was cut.  A good quality grass hay grown in the fertile soils in the south will have greater nutritional value than poor quality alfalfa hay from anywhere in the country.  Bahia grass that is well managed and cut at the right stage of maturity is more nutritious than bermudagrass that is poorly managed and allowed to get too mature before it is cut.  Well managed bermudagrass hay from this part of the country often tests higher in nutrients than cool season hays that were poorly managed.  My files are full of hay analyses such as these that demonstrate that the buyer isn’t always getting what they expected by purchasing a certain species of hay.  For this reason, each unique load of hay (different growers, different cuts, etc) should be analyzed before you buy it, or at least before you feed it.  If you buy small amounts of hay more frequently, at least sample every 3rd or 4th load so that you get an idea of an average quality for the source you are using.  The North Carolina Department of Agriculture will analyze hay samples for $10 and there are many private labs that offer hay testing services as well.  Your local Extension Agent has the forms and tools to help you get your hay analyzed and to help you interpret hay sample reports.

From NC to NE and back……

Posted in Cattle, Horses on September 22, 2011 by extensionlivestock

While visiting the Pitzer Ranch for their fall production sale, we were fortunate to get to see a bit of “the rest of the story”. The hayfields stretch out for miles and miles beyond the barns and houses of the ranch.

What a different world!  As we drove around – for miles and miles and miles – I was fascinated with the differences and similarities in agriculture between Nebraska and North Carolina.  The area of NE we visit stocks their pastures at about 15:1 – acres to cows that is!  A bit further east where rainfall is more plentiful, it’s closer to 4:1.  Land prices are a bit different too – $400 -$4000 an acre depending on productivity.

Just like in North Carolina, they grow some good hay and some of that classic “better than a snowball” type!  Hay across the country is short this year so it will be more important than ever to get your hay bought or at least found as early as possible.  Estimating how much you will need for the winter and trying to buy it early can save you money and worry and possibly even some animal health concerns.  If you wait till the only hay left is the BTAS kind, it could be expensive from the standpoint of bagged feed to supplement poor quality or from vet bills to rescue your horse from the pitfalls of low digestibility hay.

Buy hay that has already been analyzed for nutrient content if you can.  Until you develop an eye for characteristics that determine the feeding value of hay, buying hay that has not been analyzed is like buying a pig in a poke. That said, it’s a rare find, analyzed hay.   So, arm yourself with the knowledge to do a good visual assesment.  There are 4 main characteristics you need to evaluate:

Texture – texture will give you an indication as to the maturity of the plant at harvest.  Presence of seedheads and stiff stems tells you the hay should have been cut earlier and is lower in quality.  If the hay is leafy and pliable – having more leaves than stems – you know the hay has optimal nutrition for the type plant it is.  That said, different forage species have different potential for quality.  Legume/grass mixtures and cool season plants have more quality potential than warm season grasses as a general rule of thumb.

Aroma – mold has a distinctive odor you should learn to identify as it indicates the hay was either cured or stored improperly.   Mold will appear as a grayish-white dust when you pull apart a bale of hay, or as a white flaky substance in tightly packed sections of the bale. Horses have a lower tolerance for molds than ruminants and as a rule, moldy hay should be avoided.

Foreign matter – weeds, sticks, rocks, clods of dirt, wire – these are things you’d really prefer not to have in your hay and are signs that maybe there were a few too many things on the plate of your hay grower that got more attention than the hay.  While the occasional dehydrated snake may or may not give you the willies, hay containing such things should be sorted through and fed with caution – and your horses should be vaccinated and boostered annually for botulism.

Color – Used alone, color is a relatively poor measure of quality – be sure to consider all of these factors together. Bright green hay indicates higher levels of vitamin A.  A light tannish color indicates the hay may have layed in the field longer till it dried or was stored somewhere that sunlight could reach and bleached the exterior of the bale only.  Dark brown hay could indicate the presence of clovers in the hay or it could mean the hay was baled wet and is heat-damaged.

Do be sure to analyze the hay once you’ve bought it – and check the box to test for nitrates.  The test costs $10 and can make a big difference in how you feed your animals.

Also, buy – or at least calculate your price – on a weight basis rather than by the bale.  You’d be amazed at the variation in bale weights – but everybody assumes a bale of hay weighs 50 pounds.  At 50 pounds per bale, $6 a bale hay costs $240 a ton.  When the bales weigh only 40 pounds, that same $6 a bale hay costs you $300 a ton.  Calculating a per ton price gives you one more tool in making a good comparison and a good buy on hay.

Just like in Nebraska, North Carolina farmers love the land and tend it with care and reverence.  Get to know the farmer who grows your hay.  You’ll appreciate the friendship and so will he (or she)!

A little bit of football and some cow tips……

Posted in Cattle on September 12, 2011 by extensionlivestock

 

When the weather starts cooling, it doesn’t only mean that football season is around the corner, it also means that a large percentage of cattle farms in this region are beginning one of the most intense and busy seasons:  calving time.  Fall calving allows for many different options when marketing, but that’s a different topic for a different article.  Here we’re going to look at management and some issues to watch for.

 

–       Pasture

  • Make sure you have a pasture ready for calving.  Hopefully this pasture is clean with plenty of good forage available.  We need to take care of the cows and their calves need to have a good place to begin their lives.  We typically designate a “clean” pasture as a pasture that hasn’t been grazed in 6-12 months.  However, many farms cannot accommodate that.  If we can get anywhere from 2-4 months, our pastures are “clean-er” and we can hopefully look to improve the chances of disease and heavy parasite (worm) loads on our animals.

–       Body Condition Scoring

  • This is a very important concern when we start looking forward to calving season.  As a general rule of thumb, we prefer to see heifers in a BCS of 6-6.5 at calving time, and cows in a BCS of 5-5.5.  We need to start looking at our animals at least 30-60 days prior to calving to allow for bringing them to the appropriate level if they are lacking.

–       Calving Difficulty

  • Know the proper presentation for a calf.  Make sure you have a calving “toolbox” prepared. A toolbox should include OB chains and handles, lubricant, calf jack (optional), gloves/palpation sleeves, and a flashlight with new batteries.  If you are having problems, it may be a good idea to give your regular veterinarian a call so they will be prepared to come assist you.  If you haven’t had any progress within 30 minutes it is advisable to get your veterinarian to come out.

–       Health Concerns

  • Here is a list of some issues generally seen during the fall and winter seasons:
    • Hypocalcemia (milk fever)
    • Cow will not be able to stand, if she does, she will stagger and soon fall.  Advanced stages will have them down and their head and neck will be facing their back end.
    • Hypomagnesemia (grass tetany)
    • Cow will stagger; advanced stages will have the cow down and displaying convulsions.  This is usually put under “spring season” illnesses, but is also prevalent in the fall season because of increased grass growth.
    • Pregnancy Toxemia
    • One of the first noted abnormalities is often loss of body condition over 1-2 weeks. Decreased appetite, rumination, fecal production, and nose-licking are general signs of illness. With time, affected cows become markedly depressed, and weak.

 

Developing a management plan for your operation can help your cattle throughout the fall calving season and into winter.  Many of the health concerns listed are treatable with proper minerals and good quality forage.

Body Condition Scoring in Horses

Posted in Horses on July 15, 2011 by extensionlivestock

Body Condition Evaluation Areas

Body condition scores (BCS) are based on body fat indicators in six areas on the body that help to estimate stored energy.  Research has shown that the amount of stored energy influences many physiological functions and can greatly influence the performance of equine athletes, fertility in broodmares, stallion performance, and the growth of young horses.  The system most commonly used is the Henneke system which was developed by Texas A&M University in the 1980’s as a way for veterinarians, nutritionists, farm managers, and horse owners to evaluate the nutritional status of horses.  This system evaluates six areas on the body by visual appraisal and palpation.  Each area that is evaluated is given equal emphasis when assigning the score, which helps account for physiological and conformational differences in horses.  A systematic method of scoring is important as not all horses are proportioned equally, and long, tall horses will appear leaner at first glance than horses that are compact.

The evaluator will visually observe and then feel the six main areas on the horse’s body, and compare his/her observations to the descriptions on the BCS scorecard to assign a score.  All of the conditions must be met for a given score in order for the horse to be assigned that score.  However if a few criteria are not met, the score is often adjusted up or down in one-half-unit increments as indicated.  When evaluating body condition, there are several key points to keep in mind to get the most accurate estimation.  First, horses that are fed free-choice hay will often develop a prominent belly as will foals that are just weaned.  This gut distention should not be confused with fat.  Additionally, the enlarged belly of a pregnant mare will actually pull the skin and muscle tight over the top line and ribcage (especially in the third trimester) so these areas should not be used in determining BCS during this time.  Some horses have unique conformation or problems such as prominent withers, flat loins, weak top lines, or injuries that make it necessary to eliminate certain criteria when making evaluations.  Lastly, don’t ever be fooled by long hair coats, and make sure to use observations made by palpation when the hair coat is long enough to make the horses visually appear fatter than they really are.

 Ideal body condition will vary somewhat depending on the use of the horse but will range between a score of 4 (moderately thin) and 7 (fleshy).  A horse below a BCS of 4 is not considered to be of adequate weight by the NC Horse Council’s Guide to Minimum Standards of Care.  A BCS of 5 (moderate) is ideal for performance horses as they will be better able to effectively use dietary and stored energy toward the performance activity, with a slower onset of fatigue and improved thermoregulation.  Performance horses in a thinner condition are more prone to early fatigue because they have to rely almost entirely on energy that is derived from the daily diet.  Alternately, fatter horses will require more energy to dissipate heat and cool themselves than properly conditioned horses thus they will have less fuel available for performance.  Young growing horses should be maintained in a moderate BCS of 5 as well.  Broodmares should kept in a good body condition throughout the year and ideally go into the breeding season in a moderately fleshy to fleshy body condition score between 6 and 7.5.  Many research studies over the years have shown that mares in higher body condition cycled earlier, had higher pregnancy rates, had lower number of cycles to conception, and sustained more pregnancies.  Furthermore, once mares foal they will need plenty of stored energy to support the demands of early lactation while maintaining enough condition to rebreed efficiently. 

 BCS should continually be monitored and feed adjustments made to achieve optimal condition and to subsequently achieve maximum reproductive and performance efficiency.  Changing BCS upward or downward should be done slowly and carefully taking equine digestive function into consideration.  Thus weight gain or loss should be controlled by gradually increasing or decreasing the horse’s energy intake such that the horse loses or gains 1 BCS over a period of about 8 weeks.  This can be accomplished by either increasing or decreasing the amount of grain/concentrate, or by choosing a  feed with a greater or lesser energy density.  Providing feeds with greater energy density is a safer way to increase BCS in that feed volume does not have to be increased to provide more caloric intake.  Changes in feed volume, or between feeds with different nutrient profiles, should be done gradually.  In situations where dramatic increases in concentrate quantities are necessary, increase feed intake gradually over a 10-day to 2-week period of time so the digestive tract can adjust.  When changing between feeds with different nutrient profiles or physical forms (textured versus pellets), some changes can be made almost immediately; some require a few days; and others will require a week or longer to assure a safe changeover.  For overweight horses that are on all forage/hay diets, intake of fresh forage may have to be reduced by muzzling or confining the horse to a dry-lot paddock for a period of time.  Another alternative is to feed a hay with a lower digestible energy content such as a more mature hay.  This will satisfy gut fill without adding more caloric intake; however when changing to a lower quality hay, the horse will need to be provided a vitamin and mineral supplement to maintain health.

A Genetics Teaser………

Posted in Cattle on June 20, 2011 by extensionlivestock

In past articles, I have given brief overviews into the realm of reproductive strategies and very basic genetics.  This time around, I would like to dive into the genetics just a bit more and hopefully give you a better understanding of how we utilize genetics in the cattle industry.

When we think of genetics, we automatically think of high school biology and the Punnett squares where we figure out what color hair something has or whether or not our neighbor has a hitchhiker’s thumb.  The genetics we deal with in the cattle industry are much like these, with the exception that we’re looking at much more than we have in the past.  Genetics has two major terms that we need to understand:

Phenotype – an observable category or measurable level of performance for a trait in an individual (ie. hair color, weight, average daily gain)

Genotype – the actual genetic makeup of the individual

Now after that, we start to get into how genetics are utilized and what helps us to understand them.  The phenotype is a product of the interaction between the genotype and the environment.  As an example – if Cow A has the same genetic makeup (genotype) as Cow B in relation to heat stress, but Cow A lives in Alaska and Cow B lives at the beach in Florida, Cow B will not have the same qualities as Cow A when it comes to average daily gain or possibly reproductive efficiency.  This would be because with Cow A and Cow B being susceptible to heat stress, the animal living in the cooler environment will perform to a higher level than the one in the heat.  This is an example of phenotype being directly related to the interaction between the genotype of the individual and the individual’s environment.

When we talk about identifying genetics for certain operations, there are some key points that need ironing out:

  1. What kind of production system are we using? (ie. seedstock, purebred, feeder calves, etc.)
  2. What is our base nutrition system? (ie. forage, supplemental feed, mob grazing)
  3. What is our market? (ie. southeast, mid west, retained ownership)

Depending on which operation we are dealing with can dictate how we utilize selection based on genetics.  For example, if we’re looking at feeder calf markets as our operation goal, we need to utilize a terminal sire and possibly look at our base herd being a 50/50 cross breed (Example 1).

Example 1.

Brood cow base:  50% Angus – 50% Hereford cross bred cows (Black Baldies)

Terminal Sire: Simmental

Potential Gain from heterosis: +23.3% lbs. of calf weaned per cow

Utilizing a system like this allows us to make the most out of a genetic cross, because the very definition of hybrid vigor (heterosis) is the measure of superior performance of a trait of the crossbred individual over and above the average of performance of that trait of the two parental breeds.  Simplified:  how well an offspring performs above the performance of its parents.  Doing this gives us more bang for our buck, and allows us to see increased production from our herds.

Developing plans based on genetic information is becoming more common today than it has been in the past.  Everyday there are new developments in the genetics industry.  Today we can have our animals DNA tested to see what genes they are carrying that will directly relate to how well they will perform on birth weight, weaning weight, yearling weight, calving ease, tenderness, marbling, and a list of other traits.  While genetics is something that has been around for centuries, with today’s technology we are now able to utilize the actual data from individual animals more accurately and in depth, which allows us to make profit production decisions for our operations.  I will have more information on this in future articles.