Evaluating Cow Nutritional Status
The early onset of winter, extreme cold conditions, and marginal hay quality have contributed to cattle stress and a poorer nutritional status of cows than normal. Visual appraisal of cows for flesh and body condition is useful in evaluating their status, implications for production, and appropriate feeding strategies.
Visual appearance of cows for body condition provides a useful assessment for determining current and future feeding needs. Body condition can be determined by prominence of skeletal features, evidence of fat deposits, and general appearance of angularity versus blockiness. The degree of thinness reflects the severity of nutritional inadequacies. Nutritional stresses are the primary direct or indirect cause of failed or marginal performance, whether it be poor re-breeding, weak unhealthy calves, low milk production and weaning weights, or disease and death.
Body condition scoring is an objective approach to evaluating and describing condition for a more precise appraisal of status and managerial implications. Scoring is done on a 1 to 9 scale. Body condition score 1 is at the extreme thin end of the scale relating to cattle being extremely emaciated with no fat, little muscle, obviously weak, and survival being at risk. Body condition score 9 is on the very obese end of the scale and cows are so round and heavy they have impaired mobility.
When evaluating body condition, make sure you are estimating the degree of fatness and flesh and not hair coat and gut fill. Some adjustment may also need to be made for age, as with advancing age more weight and condition is carried lower on the body rather than over the top line. Dairy types also tend to deposit more fat internally rather than in visible subcutaneous locations.
In reality, the extremes are rarely seen and it is cattle scoring between 2 and 8 that are of concern and described below.
Score 2 - Emaciated
All ribs and bone structure easily visible, very little visible muscle tissue
Score 3 - Very thin
No fat over ribs or in brisket. Backbone is sharp and highly visible but some apparent muscling in hindquarters.
Score 4 - Thin
Ribs visible with shoulders and hindquarter showing modest muscling. Backbone visible but rounded rather than sharp.
Score 5 - Moderate
Backbone is not visible, areas on side of tail head are full but not rounded. Only last two or three ribs can be seen. General good overall appearance.
Score 6 - High Moderate
Ribs are fully covered, back appears slightly rounded and evidence of fat in the brisket and over tail head.
Score 7 - Good
Back appears well rounded due to fat. Brisket is full and tail head shows pockets of fat.
Score 8 - Obese
Back is square due to fat, brisket is thick necked and distended with heavy fat pockets around tail head. Deep blocky appearance.
Cow weight and condition fluctuations throughout the year are normal. Productive cows are often in low condition in the fall and then after weaning regain 50 to 150 pounds in the fall and early winter months to winter and calve at a targeted moderate degree of condition. For average frame size cows, each condition score represents approximately 80 pounds of body weight. Under extreme conditions weight loss of over 4 pounds per day and the loss of 1 body condition score over several weeks has been seen.
A cow with a body condition score of 5 is considered to be in average flesh and should be the minimum target for mature cows at calving. A body condition score of 6 is suggested for bred heifers as they are likely to experience a greater energy deficiency and weight loss after calving. There are many consequences associated with letting cows get run down to the thin or very thin condition scores. They are more vulnerable to stress and disease and often plagued with problems such as calving difficulty, weak scour susceptible calves, poor re-breeding, and lower weaning weight calves.
Once cows have lost significant condition it takes a more complex and costly ration to put the weight back on than it would have to maintain weight. Gains of over 2 pounds per day over a 90-day period are needed to recondition a body score 3 cow to body score 5 by calving. If cows are in thin to borderline condition late in gestation, it is infeasible to have them calve at optimum calving condition targets.
Feeding changes need to be made so there is no additional weight loss by thin cows in late gestation and possibly some improvement by calving, realizing many cows will calve at a borderline condition. It is critical that thin cows in late gestation be on a complete balanced nutritional program including appropriate protein, vitamin, and mineral supplements to meet their requirements to calve in good vigor and produce a strong healthy calf.
Since a primary concern with thin calving cows is subsequent reproduction, some further feeding adjustments are called for in the period between calving and breeding. Early calving cows, which calve in borderline condition of 4 and are fed after calving to gain weight prior to and during breeding, have a high likelihood for good re-breeding. Late calving thin cows or cows calving at body scores of 3 are unlikely able to compensate in the limited time to achieve high reproductive rates.
While body condition scoring is very useful and easily done several other options may also be used to determine cow nutritional status for specific nutrients. The collection Sand analysis of blood and liver biopsy samples can be used to evaluate status for some vitamins and minerals. Blood urea nitrogen levels can also be used as a guide to assessing protein inadequacies. Due to analysis costs and collection procedures such testing is often limited to a representative sample of the herd and is done by the herds veterinarian.
Body condition Score 4
The backbone is visible.
The ribs can be seen.
Flat muscling in quarter.
Body condition Score 5
Backbone is not visible.
12th and 13th rib visible when shrunk.
No visible fat deposit in brisket.
Body condition Score 6
Smooth over top line.
No ribs visible.
Hind quarters are full.