Caustic Burno
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Better keep a close eye on Camp. This is better than ringling Bros. we could sell tickets. LMAO
Salt – Drought Management Tool for Beef Producers
Larry L. Berger, Ph.D.
University of Illinois
The western half of the U.S. experienced one of the worst droughts recorded since the 1930s, during the summer of 2002. Beef producers were the hardest hit. Many were forced to liquidate cowherds or drastically reduce numbers. As a result of the drought hay prices have increased dramatically, with beef-quality hay selling for over $100 per ton. Although corn prices have increased, many beef producers could still buy corn for $2.50 per bushel ($90/ton). At these prices, the cost per unit of digestible energy greatly favors corn. Although more-normal rainfall has returned to some areas, many ranchers are concerned whether they will have enough forage for the upcoming grazing season. With higher beef prices on the horizon, producers are eager to evaluate alternative feeding strategies as an alternative to further reductions in herd size. This paper will review recent research dealing with supplementation of grazing cattle and the ability of a salt-limited supplement to reduce cost when forage resources are limited.
Surviving a Drought:
Beef producers who survive best during a drought are those who make sound management decisions and review them regularly. Balancing the forage availability with the demands of the cowherd requires that the biology of both systems be understood. Predicting future forage production based on previous rainfall, time of year, and current grazing pressure are essential to projecting supplement needs.
Supplement needs will depend on whether cows are deficient in energy, protein, or both. Cows that are energy deficient will exhibit one of more of the following: weight loss-delayed puberty, increased interval from calving to first estrus, suppressed estrus and ovulation, weak calves, decreased milk production, and reduced immune response. Inadequate protein intake will often reduce dry matter consumption resulting in a greater negative energy balance. Consequently, a protein deficiency often has the same signs as an energy deficiency and may also include fetal resorption and premature parturition. Most experts recommend meeting the energy needs first and then the protein requirement by replacing the energy feed with one that is high in protein, and similar energy.
When producers think about supplying additional energy, they are often tempted to compare cost on a "dollars per ton" basis rather than a "dollars per unit of digestible energy as total digestible nutrients (TDN)" basis. The following table shows the cost of corn (90% TDN), low quality hay (46% TDN) and average quality hay (54% TDN) at four different prices.
Table 1. Relative cost of energy (TDN) for beef cows based on corn price, hay price and hay quality.
Unit cost of feed
$/ton
Corn - 90% TDN
$/ton of TDN
Hay - 46% TDN
$/ton of TDN
Hay - 54% TDN
$/ton of TDN
60
66
130
111
80
88
174
148
100
110
217
185
120
133
260
221
Although most beef producers do not feel comfortable limit-feeding high-grain diets to beef cows, the economics can be very favorable (Table 1). Loerch et al (1996) showed that beef producers could save at least 50 cents per day by limit-feeding cows compared to hay. If corn can be purchased for $2.50 per bushel, average quality hay has to be less than $50 per ton to compete on an equal energy basis. The question then becomes how best to supply the corn, grain by-product, or molasses based supplement to the cows.
Sawyer and Mathis (2000) did an in-depth review of the different supplement delivery systems, primarily comparing hand feeding versus self-feeding for beef cows. In their comparisons the weekly cost of daily feeding ($201) was much greater than providing a self-fed supplement three times a week ($86) or once a week ($53). The only potential advantage of hand-fed supplements is that the variation in intake among cows may be less. This assumes that adequate bunk space is provided so that only the cows at the top of the pecking order get their share. The amount of bunk space required to achieve uniform intakes is much greater than most producers anticipate. Wagnon (1966) showed that 2.5 linear feet of bunk space per head was ideal for range cows to minimize intake variation and allow all cows to consume the supplement simultaneously. Combining the labor and bunk space requirement makes hand-feeding an expensive alternative.
An additional advantage of the self-limited supplement is that the self-feeder can be moved to distribute the grazing over the entire pasture. Cattle often over-graze close to the watering source and around protected areas. By moving the self-feeder to the opposite side of the pasture, a more uniform grazing distribution can be achieved.
Salt-limited supplements:
Salt is the most common ingredient used as an intake limiter on pasture. North Dakota researchers (Schauer et al., 1999) showed that salt (16%) was equal to hand-feeding and superior to anionic salts (ammonium chloride and ammonium sulfate, 5.25%) and calcium hydroxide (7.0%). Supplements were 22% crude protein and were based on wheat midds, barley malt sprouts, and soybean hulls. The calcium hydroxide-containing supplement was fed in the meal form; all other supplements were pelleted. Supplements containing the limiters were fed in portable feeders, while the hand-fed supplement was fed in a bunk. The researchers replicated this trial over two years beginning on July 20 and June 21 and ending October 12 and October 8, in years 1 and 2, respectively. Seventy yearling steers grazing native range were used for both years. As shown in Table 2, steers gained 1.83, 1.96, 1.59 and 1.58 lb/day for the hand-fed, salt, anionic salt mix and calcium hydroxide treatments, respectively. The steers that did not receive supplementation gained 1.23 lb/day.
Table 2. Influence of supplementation program on performance yearling steers grazing native range.
Item
Control
Salt
Anionic salt
Calcium Hydroxide
Hand-fed
Std. Errors
Initial wt, lb
768
772
771
771
762
6.00
Final wt, lb
889
963
930
927
942
10.00
Supplement intake, lb/day
-
5.47
6.27
4.68
3.95
0.41
Intake, % body weight
-
0.61
0.72
0.53
0.46
0.04
Gain, lb/day
1.23
1.96
1.59
1.58
1.83
0.11
Source: http://www.ag.ndsu.nodak.edu/streeter/9 ... lement.htm
All supplements increased (P <0.05) the final weight above the control steers. Supplement intake as a percent of body weight was lower (P <0.05) for the hand-fed steers than the salt and anionic salt supplemented steers. Efficiency of supplement utilization can be calculated by dividing the supplement intake by the improvement in gain above the control steers. For example, the salt-supplemented steers had an efficiency of 7.49 ((5.47 lb supplement/(1.96 – 1.23 lb gain) = 7.49). The efficiency of utilization of the anionic salt, calcium hydroxide, and hand-fed supplements was 17.42, 13.37, and 6.58, respectively. The salt-limited supplement required approximately half the feed per unit of weight gain above the controls as the other two limited supplements. Because the salt dilutes the energy in the supplement, the efficiency of the hand-fed supplement (6.58) is expected to be greater than the salt limited (7.49). However, if we remove the salt and multiply the supplement intake by 0.84 (16% salt, 5.47 X 0.84 = 4.59 lb), and then divide by the gain above controls (0.73 lb), the resulting efficiency of 6.29 is equal to the hand fed supplement. The salt did not reduce the efficiency of supplement utilization. Although no economic comparisons were included in this paper, based on previous research (Sawyer and Mathis, 2000), the salt-limited supplement would have been the most profitable.
Uniformity of Intake:
One of the goals of any supplementation program is to deliver the desired amount of supplement to each animal in the herd. For example, if a producer hand-feeds 40 lb of supplement to 20 heifers, they often assume that each consumed the targeted 2 lb/head. However, if individual consumption is measured it is likely that 2 or 3 heifers will consume very little supplement, 3 to 5 heifers will consume between a half and 1.5 lb, 8 to 10 heifers will consume between 1.5 and 2.5 lb, 3 to 5 will consume between 2.5 and 3.5 lb and 2 to 3 heifers will consume more than 3.5 lb/day. The point is that less than 50% of the herd is getting close to the desired amount. Factors such as bunk space, age of animal, breed, social dominance, previous experience, and form and amount of supplement can affect the variation in intake when hand-feeding (Bowman and Sowell, 1997).
One concern expressed by producers considering a salt-limited supplement is the variation in salt appetite between individual animals. Although this is true, most data shows that the variation in intake is no greater than with hand-feeding or alternative delivery mechanisms. For example, Harvey et al. (1986) individually fed 24 steers in each of two years. Half the steers were fed a soybean meal based supplement containing approximately 31% salt and the other half the same supplement without the salt. Half the steers were fed either hay or corn silage ad libitum. The coefficient of variation in average salt intake for the individually fed steers varied from 5.4% to 9.7% for the whole trial. The fact that these steers were individually fed probably reduced the variation compared to being fed in a whole-herd environment. Also the coefficient of variation would be greater for shorter time periods than the 78 and 112-day trials.
In comparison, when Kendall (1980) offered grazing heifers cubed barley-soybean meal supplements or a molasses-urea block, the coefficient of variation in supplement intake was 31% and 57%, respectively. Bowman summarized numerous trials comparing dry supplements, blocks or liquids for both cattle and sheep and reported that the coefficient of variation in supplement intake averaged 41%, 79%, and 60%, respectively. Salt-limited supplements were not included in this review so it is not possible to make direct comparisons.
Management of Salt-supplements:
Adjusting the salt level in the supplement is one approach to achieving the targeted average intake. The proportion of salt in the self-fed supplement may vary from 5% to 40% depending on the animals and forage supply. If producers want to restrict intake to 1 to 2 lb per day for mature cows on range, then 30% to 40% salt may be required. In contrast, yearling cattle grazing high-quality forage may require only 5% salt initially to limit intake to a pound per day. However, as the cattle adjust to the salt and the grass gets more mature and less plentiful, 20% to 30% salt may be required to maintain the desired intake. California researchers reported that 8% to 10% salt was required to limit concentrate intake to 1% of body weight for yearling steers grazing lush irrigated pastures.
One approach to minimizing the number of adjustments in salt concentration is to include monensin in the supplement (Muller et al., 1986). Monensin, marketed as Rumensin, is cleared as a feed additive to increase daily gain in grazing cattle. When salt and Rumensin were used together, the number of adjustments required to obtain the desired intake was half that of salt alone (3 vs. 6) in the Muller et al. (1986) studies. The average minimum and maximum salt levels required to achieve the target intake was also lower. The self-fed supplement containing salt and Rumensin gave the same average improvement in daily gains (0.20 lb) as hand-feeding the Rumensin supplement without salt. These data show that salt, an already proven effective intake regulator, can be made even better when fed in combination with Rumensin.
Hand-feeding the salt-supplement mix for a week before providing access to a self-feeder is recommended, especially if the cattle are hungry. Intakes should be monitored to know when adjustments in salt concentration are required to achieve the targeted consummation. When using salt-limited supplements, plenty of clean fresh water should be available at all times. It is not uncommon for water intake to double when salt-limited supplements are fed.
In summary, using a salt-limited supplement is an effective and economical management tool for beef producers coping with a drought.
