A significant amount of information can be determined from analyzing how cows look. Much the same as in the popular press, growing attention is being paid to detecting skinny cows and determining what “working” weight is and what is “too thin.” The day to day 24-7 nature of dairy farming is providing data that concludes that detailed observation of Body Condition Score can help to prevent health, reproduction and production problems in dairy cattle.
Do You Know the Score?
Traditionally nutritionists, vets and farmers have relied on the five point BCS system outlined by Ferguson and collaborators in 1994. The challenge with this system is that it relies on trained individuals to be consistent in their scoring approach and assess each cow in a repeatable manner, something that it typically not the case. Moreover, BCS tells us nothing about the internal fat stores. Body condition scoring should be monitored by someone that has be trained and who is well acquainted with the scoring guide. Some recommend using an outside source to score alongside a permanent employee a few times a year to ensure scores do not drift. This frequently happens when one person is responsible for body condition scoring. “When individuals see the same herd every week, their scores can easily shift up or down, which can be corrected by working with an outside expert.”
Ultrasound and Back Fat Mobilization
A solution to human BCS assessment issues is the use of ultrasound as an alternative to assess total carcass fat. A report that discusses ultrasound results summarized. “When the thickness of back fat of dairy cows was assessed in a 2012 trial by van der Drift, back fat thickness decreased by 35 ± 26 % from the week prior to parturition to 8 weeks after parturition. The marked decrease in back fat thickness suggest mobilization of body adipose stores to aid in maintaining energy balance while also showing that not all cows experienced the same onset and extent of mobilization. This difference in back fat mobilization may be due to more than just differences in energy balance. The contribution of other body adipose stores may also play a role.” (Miner Institute: Are skinny cows really skinny?)
Transducer Scans Give Reliable Measurements
A newer method to determine total body fat stores utilizes the same principles as van der Drift and others, but takes into account the contribution from both back fat and kidney fat. This method uses a 3.5 mHz transducer that scans the animal at the first lumbar vertebra and the 13th rib for assessment of kidney fat depth and approximately 15 cm for the cow’s midline. Clipping the cow may be necessary to improve image quality and ensure proper measurement. When carcass kidney fat was compared to ultrasound measurements of kidney fat depth, there was a strong correlation (r2=0.93), suggesting that assessment of kidney fat depth via ultrasound can provide a reliable means to measure a crucial contributor to whole body adipose stores.
What Do You Know About Thin Cows and Heifers?
There are significant issues relating to thin cows and heifers.
- Cows that lose one or more BCS units from calving to 60 days in milk are much more likely to be anovular (not cycling) compared to cows that lose less than 1 BCS unit (40.6% vs. 17.9%)
- Under-conditioning, or thinness, can frequently lower production and milkfat levels because of insufficient energy and protein reserves.
- Thin cows often do not show heat or conceive until they start to regain—or at least maintain—body weight. In feeding these animals, care must be taken to maintain production while increasing body reserves.
- Thin heifers may not grow rapidly enough to reach puberty by 13 to 15 months of age.
- Thin heifers may also be too small to calve at 23 to 25 months or to carry enough weight to maintain a normal first lactation.
- Thinner cows are at a greater risk of infectious or inflammatory diseases, such as uterine infections.
- Thinner cows were less able to compete for scarce feed resources, prolonging hunger and further increasing the risk of disease.
- Thin cows at calving become even thinner cows at peak milk production. Any animal below BCS 3.0 must be managed immediately to increase BCS.
- If cows enter lactation with lower-than-desirable BCS, they often don’t peak as high and are hard to get bred back. These cows typically have higher intakes once they enter the milking string, but the extra energy they consume from the ration is used for daily maintenance rather than milk production and reproductive function.
- Field observations suggest that cows that are too thin at calving (BCS <3.25) may have insufficient body reserves to support normal peaks or may exhibit a loss of persistency in milk production. In either case, whole lactation milk production suffers.
What to Do
Early lactation thin cows that are not high producers are not getting enough energy. Be sure that all nutrients are balanced properly and that dry-matter and water intakes are adequate.
Heifers that Score below 3- may indicate a nutritional problem. If heifers are allowed to become too thin, they will not grow at the proper rate and may have reproductive problems later on.
By boosting energy and protein levels, you can safely provide the extra condition your cows need and help them perform at their genetic potential. This will also be beneficial for milk production and reproductive performance.
Although well-managed farms will sometimes have a small proportion of thin cows because of health issues (e.g. mastitis, metritis or lameness cases), ensuring that young and mature cows calve at the correct BCS minimises the need for intervention.
Take A Picture!
Because of the changing nature of Body Condition Scoring having an evolving and accessible record, can be as simple as a camera click away. The value of a picture record is that, when taking BCS photos of the same cow 45 to 60 days later, a producer can determine if the management changes are having the desired effect.
Producers are encouraged to body condition score cows at least four times during the year to determine best management practices: 1) Weaning, 2) Pre-Breeding 3) Pre-Calving and 4)Late Lactation. Some commercial programs provide the flexibility of using photos of cows within your own herd or cattle type to use in the reference gallery. No matter what color or breed type of cattle you own, you can now build your custom collection of BCS photos to use in your reference gallery. Once producers have collected BCS measurements from a pasture or group of cows at one point in time and then followed up with BCS measurements at another point in time, they can calculate the mean or average for a selected date range. It then becomes easy to determine if cows are gaining, slipping or maintaining their condition.
Is Thinness an Individual Problem or Herd Crisis?
Producers must pay attention to those cows that are consistently lower on the scale. If their condition begins to slide, that might be an indication that the rest of your herd might begin to slip as well. Being able to look at your herd and determine how healthy it is based on body condition scores means you can make adjustments to increase pregnancy rates and calf health. It’s just one more, no-cost way to add to your bottom line.
The Bullvine Bottom Line
Body Condition Scoring, when used correctly, can be a great indicator of the success or failure of your dairy nutrition program and should be an ongoing activity. It is one more tool to use to improve herd health and profitability. Got skinny cows? What’s the score?