by: Wes Ishmael
�Thin cows do not compete.�
That's a statement of fact that Kris Ringwall, Extension beef specialist at North Dakota State University (NDSU) believes should be written on barn walls and painted on pasture fences. Right along with: Thin cows need more feed.
Given the historically high cost of replacing females and the historically high opportunity cost of keeping cows in the herd, neon colors might be most appropriate.
Though obvious, Ringwall is getting at the effect cow body condition has on herd reproductive rates. He's also making the point that between geographic forage growing seasons and a beef cow's production cycle, adequate nutrition and the opportunity to adjust cow condition are most effective at certain times of the year.
�Reproduction is the most important factor in determining profitability in a cow calf enterprise,� explains Johnny Rossi, assistant professor and Extension specialist at the University of Georgia in the insightful factsheet, Body Condition Scoring Beef Cows. �To maintain a calving interval of 365 days, a cow must re-breed in 80 to 85 days after calving. Many cows in Georgia need a higher level of condition at calving and breeding to improve reproductive performance.�
�Cows will regain body condition easier when production demands are low,� Ringwall emphasizes. For the spring-calving herds in his part of the world, he adds, �As cows go out of production during late lactation and weaning, fall provides an excellent time to put weight on cows. In addition, the cow does not need to channel calories into staying warm, so do it now.�
Cow Body Condition and Reproductive Rate
�Body condition at the time of calving is the most important factor affecting rebreeding performance of normally managed beef cows,� say contributors to the extension.org website. �Body condition changes before and after calving will have more subtle effects on rebreeding especially in cows that are in marginal body condition. Body condition changes from the time the cow calves until she begins the breeding season can also play a significant role in the rebreeding success story. This appears to be most important to those cows that calve in the marginal condition score range of 4 or 5.�
The Extension.org contributors use a recent Oklahoma State University research trial as an example. �Two groups of cows began the winter feeding period in similar body condition and calved in very similar body condition. However, after calving and before the breeding season began, one group was allowed to lose almost one condition score (from 5.3 to 4.6),� they explain. �The other group of cows was fed adequately to maintain the body condition that they had prior to calving. The difference in rebreeding rate was significant (73 percent versus 94 percent). Again, this illustrates that cows that calve in the body condition score of 5 are very vulnerable to weather and suckling intensity stresses and ranchers must use good nutritional strategies after calving to avoid disastrous rebreeding performance.�
By way of refresher, the beef cow Body Condition Score (BCS) system is standardized visual assessment of cow body condition or fat cover, which reflects nutritional status; energy reserves more specifically. The score ranges from 1 (emaciated) to 9 (obese). Depending on the herd and the resources, BCS 6-7 are often considered to be optimum condition
�Poor reproductive performance is directly linked to the percentage of body fat in beef cows,� Rossi says. �Body condition scoring (BCS) is an easy and economical way to evaluate the body fat percentage of a cow. Cows can then be sorted and fed according to nutritional needs. Body condition scoring can be an effective tool for cattle producers who cannot weigh cattle, and it may be an even better measurement of cow condition and reproductive performance than weight. Most studies show that body condition decreases at a faster rate than weight loss. Therefore, body condition scoring can estimate the probability of re-breeding.�
Sorting Power
�First-calf heifers have historically been the toughest females on the ranch to get rebred,� says Glenn Selk, Emeritus Extension Animal Scientist at Oklahoma State University in his recent production comments. �They are being asked to continue to grow, produce milk, repair the reproductive tract, and have enough stored body energy (fat) to return to heat cycles in a short time frame. Two-year old cows must fill all of these energy demands at a time when their mouth is going through the transition from baby teeth to adult teeth.�
Selk emphasizes these younger cows are likely to be pushed aside from supplemental feed if they run with older cows.
�The result of these adverse conditions for young cows very often is a lack of feed intake and lowered body condition,� Selk explains. �Of course, lowered body condition in turn results in delayed return to heat cycles and a later calf crop or smaller calf crop the following year.�
Looking at 21 years worth of commercial cowherd data from NDSU, Selk explains, �The average two year old is about 20 percent smaller than her full grown herd mates. There is little wonder that the younger cows get pushed away from feed bunks, hay racks, or supplements fed on the ground. The results of the size differences and the need to continue to grow are manifest in the lower body condition scores noted in the very young cows.�
At the same time, using the same data set, Selk says, �The very old cows (10+ years) are experiencing decline in dental soundness that make it difficult for them to maintain feed intake and therefore body condition. The two-year old cows and the 11 year-old and older were significantly lower (0.3 or more units) in body condition score than middle-age cows.�
Consequently, Selk adds, �It makes sense to sort very young cows with the very old cows and provide them with a better opportunity to compete for the feed supplies. By doing so, the rancher can improve the re-breeding percentages in the young cows and keep the very old cows from becoming too thin before culling time.
Cow Costs are Increasing
Along with maintaining condition for reproduction, sorting and paying attention to times of the year when condition can be added most effectively has plenty to do with controlling costs, too, Ringwall says.
Based on data from the North Dakota Farm management education program and from the Center for Farm Financial Management at the University of Minnesota (FINBIN), Ringwall notes that almost three-fourths of the direct expenses of a cow can be traced back to feed-related items.
�Although current market trends tend to muffle these expenses, they still are expenses, so long-term survivability relates to the ability to control expenses,� Ringwall says. �A quick look at some of the numbers available from FINBIN shows that production costs are escalating. Annual direct costs are approaching $500 per cow, or almost $1.40 per day.�
If feed-related expenses continue at 75 percent of direct expenses, Ringwall notes that feed costs of $1/day will soon be common.
�Of course, there still are big, medium and smaller cows. There are cows that eat at bunks and cows that walk a mile for lunch. There are cows that could fill a milk bucket and those that introduce their calf to outside feed quickly,� Ringwall explains. �More than likely, all these types of cows exist in herds across the area because a lot of cows are not selected for specific traits that lower costs. Instead, they are selected for specific traits that increase production. Also, the information that is known about cow efficiency relative to decreasing feed costs is not readily implemented into a cowherd. For the average herd and typical producer, why not acknowledge those time frames when a positive impact could be made to lower total feed costs.�
Ringwall shares an example of a moderately milking 1,300-pound cow in his part of the world that will eat about 30 lbs. of good, green hay per day prior to weaning.
�After weaning, that same cow needs 26 to 27 lbs. of that same hay,� Ringwall says. �In other words, the cow is no longer milking and does not need the extra feed. However, if the feed is offered, such as during fall aftermath grazing, the cow will store that extra feed as improved body condition. Even if feed is plentiful, the producer can take feed away from well-conditioned cows and give it to the thin cows. The thin cows should respond with increased conditioning, which means they will be better prepared for winter and next year's calving.�
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