ONA REPORT

published in

THE FLORIDA CATTLEMAN AND LIVESTOCK JOURNAL


December 2012

A Practical Approach to Winter Supplementation of the Beef Cowherd


For questions or comments regarding this publication contact: John Arthington

As I write this Ona Report, we are entering into the first week of November.  Invariably, this begins the annual phone calls, visits, and e-mails with questions related to winter supplementation.  This year is certainly no exception, so I decided to focus this report on the common questions that I encounter with the anticipation that a broader group of readers might benefit from your peer’s questions.

Let’s start with a discussion of the term “supplementation”.  By definition, supplementation refers to “something added to complete a thing or make up for a deficiency . . . “; therefore, it is important that we don’t confuse “supplementation” for “feeding”.  In regards to cowherd nutrition, “supplementation” implies that the cowherd has access to a free-choice supply of forage, whether grazed or harvested.  Typically, these forage sources contain inadequate nutrients to supply the cow’s requirements, particularly during lactation, thus, supplements are required to make up for this deficiency.  Generally speaking, supplementation of a forage-based cow diet would account for about 5 to 20 % of the cow’s total dry matter intake.  Assuming that a cow would consume about 2.5% of their body weight in dry matter daily, the supplementation rate would be about 1.5 to 6 lb of supplement dry matter daily for a 1200 lb cow.  In general, the lower end of this range represents supplementation strategies primarily focused on protein, while the upper limit represents strategies focusing on both protein and energy.  The proper choice for your cowherd will be based on; 1) forage quality (how much energy and protein is being consumed), 2) cow age and stage of production (lactating, gestating, or dry), and 3) cow body condition score (does she need to maintain or gain body weight).  Throughout this article, we will refer to the amount of supplement offered or required as lb (pounds) of dry matter.  This is a very important point and should not be confusing.  The moisture content of supplements can vary greatly.  For example, many liquid feed products contain 25 to 30% moisture, or also stated, 70 to 75% dry matter.  Alternatively, most dry supplements, such as range cubes, contain less than 10% moisture, or also stated, more than 90% dry matter.  These ranges in moisture content should not be construed as suggesting one is good or another is bad, but instead simply be cautious that moisture content is accounted for when supplement feeding decisions are made.

Many of our Florida cow/calf producers manage fall-calving herds; therefore, the cows are typically near peak lactation this time of year.  Thus, their nutrient requirements are at their greatest.  So, let’s use this scenario for our discussion.

Question:  How much of my cow’s nutrient requirements are being met by forage?

Answer:  Assuming that available forage is not lacking, this question is best addressed by assessing forage nutrient content.   The following table illustrates three common forage quality scenarios.  This table estimates the amount of total digestible nutrients (TDN) and crude protein (CP) being consumed when the cows are exposed to forages of differing nutrient quality.  Also, as forage quality declines, a decrease in voluntary forage dry matter intake is represented.  This response is the result of poor ruminal digestion efficiency as a result of consuming poor quality forage.  This voluntary intake and subsequent digestion efficiency can be improved with proper supplementation.

Table 1.  Forage nutrient quality – Impact on supplementation need1

Forage Quality

Nutrients from Forage

Cow Requirement, lb

Supplement needed, lb

55% TDN

12.1

11.7

0

9.0% CP

2.0

2.0

0

50% TDN

9.6

11.7

2.1

7.0% CP

1.3

2.0

0.7

45% TDN

7.4

11.7

4.3

5.0% CP

0.8

2.0

1.2

1Assumes a 2.00%, 1.75%, and 1.50% of cow body weight voluntary dry matter intake of forage for the high (55% TDN), medium (50% TDN), and low (45% TDN) quality forages, respectively.  These values are conservative and likely favor a greater amount of suggested supplement.  Always monitor cow body condition when evaluating the effectiveness of a cowherd supplementation program.

When I respond to questions regarding supplementation, I often consider this Table as a point of reference.  Indeed, these are averages and there are several factors that may influence the exact quantity of nutrients required to be delivered by a supplement; however, this reference provides us a logical and practical place begin.  The medium quality forage example (50% TDN and 7.0% CP) is a common scenario for many Florida cow/calf production systems in the fall and early winter, so let’s start here to examine supplementation options.

Question:  Will a 32% liquid product adequate to supplement moderate quality forage?

Answer:  Usually, this type of supplement is best when TDN is marginal or adequate and CP is slightly deficient.  These products have the advantage of being somewhat self-limiting, typically about 3 to 4 lb of intake daily.  At about 75% dry matter, this would be 2.25 to 3.00 lb of supplemental dry matter daily, which would provide about 0.75 and 1.75 lb of CP and TDN, respectively.  In this situation the lactating cowherd may be protein adequate, but slightly energy deficient.  This resultant outcome is a very common situation in Florida, particularly southern Florida.  In these scenarios, many producers will overcome the energy deficit with a wide variety of commodity byproducts, such as wet citrus pulp, citrus residium, cull vegetables, or bakery byproducts – all high in energy, but low in protein.

Question:  Is Wet Citrus Pulp a good supplement for beef cows?

Answer:  Citrus pulp, wet or dry, is a good source of energy (TDN; generally 75 to 78% dry matter basis) for beef cows, but it lacks adequate CP (generally 5 to 6%).  If lactating beef cows are grazing winter perennial pastures or provided stored forages, and citrus pulp is their only supplement, then they are very likely consuming a protein inadequate diet.  This lack of protein can be overcome by providing a 30 to 32% CP free-choice liquid supplement (described above), or other high-protein supplement option, limit fed to provide about 0.75 lb/d of supplemental CP, such as 5 to 6 lb of cottonseed meal twice weekly per cow.  Either of these options (i.e. free-choice 32% CP liquid supplement or limit-fed cottonseed meal) will complement free-choice wet citrus pulp or 3 to 4  lb/day of dried citrus pulp. 

Question:  Is urea bad for my cows?

Answer:  No, provided it is supplemented properly.  Urea toxicity can occur when starving cattle are provided access to urea-fortified, free-choice supplements.  Cattle adapt to urea more slowly than natural protein supplements.  Be certain that cattle have an adequate supply of forage available when feeding high-protein, urea-fortified supplements.  In addition, young, growing cattle should be provided the majority of their supplemental protein through natural protein sources, such as cottonseed meal, soybean meal, feather and blood meal, or distillers or brewers grains.  Finally, when given an option for similar nutrient profile products, urea-fortified supplements should be substantially less expensive than natural protein options.  If not, then they buyer should almost always select the natural protein option for any class of cattle.

Question:  Which is my better option, liquid supplements or dry ingredient supplements, such as range cubes?

Answer:  Both options have distinct advantages and disadvantages.  Liquid supplements have the advantage of being able to be offered free-choice with the cows usually self-limiting their intake.  This has significant implications on reduced labor costs.  Alternatively, free-choice supplementation can also be a disadvantage, in that intake cannot be controlled when doing so may be advantageous to the system.  For example, if a product is formulated for an average intake of 4 lb/cow daily, and their supplemental requirement is only 2 lb/day, then over-supplementation may be a costly outcome.  Also, if the cows require 6 lb/d to account for a nutrient deficiency, then under-supplementation will result.  So, free-choice, self-limiting supplements have advantages and disadvantages.  Generally, dry feed supplements offer more flexibility by providing options to more closely match the supplemental nutrient requirement of the cow, but this advantage also comes with a greater cost associated with supplement handling and feeding.

Question:  Are poured blocks or tubs good supplement options for my cows?

Answer:  These supplements are generally formulated for 1 to 3 lb of intake/cow daily.  The actual amount varies depending on the hardness of the product and the inclusion of ingredients that may either encourage or limit intake.  So, similar to the liquid supplements described previously, they have the distinct advantage of being offered free-choice and self-limiting.  However, most often, their limited intake is insufficient to correct the nutrient deficits that many Florida cow/calf producers encounter.  This is not always the case, however, as some producers may have forages, particularly medium to high quality hay, that can benefit from the small amount of supplemental nutrients provided by block or tub products.

Question:  My commercial winter supplement is fortified with minerals.  Are these sufficient for my cows?

Answer:  Today, I find that most commercially formulated winter supplements are fortified with minerals.  When fed properly, these products fully supplement the mineral deficiency of the forages being consumed. Therefore, I typically recommend that cow/calf producers carefully assess the mineral fortification of their supplements and seek to discontinue providing their normal free-choice, salt-based mineral supplements during the period of winter supplementation.  When doing this, it is a good idea to provide white stock salt in your mineral feeders.  Also, remember to return to your normal mineral supplementation program in the spring or early-summer when you are finished with winter energy and protein supplementation.

Summary

Winter supplementation of energy and protein are vital to optimize the performance of our Florida cow/calf herds.  Supplementation should be adequate to support a cow body condition of 5 to 6 and should be addressed early, generally at the start of calving or after the first frost, before the cows begin losing body weight.  Be sure to properly estimate the required amount of supplemental energy (i.e. TDN) first and then assess protein.  Urea-fortified, winter supplements are logical options for mature cows, provided they are purchased at a discount compared to supplements using natural proteins with a similar nutrient profile.  Be certain that the intended range of intake is sufficient to address deficits of energy and/or protein when using winter supplements intended for free-choice, self-limited consumption.  For more information on winter supplementation of the beef cow/calf herd, please contact the University of Florida, IFAS Cooperative Extension Service at www.EDIS.ifas.ufl.edu, your County Extension Office, or contact our us at (863) 735-1314 or jarth@ufl.edu.