Nutrition and Management: Feeding Lightweight Calves

This is a fact sheet from the Nutrition and Management section of the Alberta Feedlot Management Guide,Second Edition published September 2000. The 1200 page guide is available for purchase on CD-ROM.

Take Home Message

• In a lightweight calf feeding program, the first 30 days in a feedlot are critical to success.
• Freshly weaned calves require increased nutrient dense rations due to low dry matter intake upon arrival.
• Proper nutrition and bunk management, which stimulates feed intake, can greatly reduce morbidity, mortality and improve performance in lightweight calves.
• Nutritional programs should be changed to capture new opportunities or incorporate new research data.

The art and science of feeding cattle is a challenge at the best of times. However, few challenges compare with the task of feeding lightweight calves. For the purpose of this discussion, a lightweight calf is defined as a newly weaned calf weighing less than 450 lb body weight that is shipped to an unfamiliar feed yard. Weaning, mixing, shipping, confining, handling and treating calves generate anxiety and stress for the animal. (see Recognizing and Reducing Stress in Feedlot Cattle for additional tips on reducing handling stress). The purpose of this paper will be to discuss various nutritional and management strategies that aid in feeding stressed lightweight calves.

Starting Lightweight Calves

Fresh weaned calves have low dry matter intake (DMI) (Table 1) during the first month on feed. The lack of appetite leads to reduced immune response, which results in increased morbidity and mortality. To give fresh weaned calves a proper start, an initial goal is to encourage calves to consume a well balanced, nutrient dense diet, containing at least 50% roughage.

Table 1. Dry Matter Feed Intake of Newly Arrived Calves (% body weight).

Days from receiving	Healthy Calves	Sick Calves
0 to 7 days	1.55	0.9
7 to 14 days	1.9	1.43
15 to 28 days	2.71	1.84
29 to 56 days	3.03	2.68

Source: (1)

Nutrition

Calves require water, energy, protein, macro minerals, trace minerals and vitamins. Nutritional balance is the key!

Diet Nutrient Concentration

Dry matter intake of lightweight calves is lowest during the two weeks following arrival. Therefore, starter or receiving rations should be palatable to maximize intake. Receiving rations should provide a greater concentration of the required nutrients than rations formulated for cattle that are already established on feed. Starter calf diets should have elevated concentrations of energy, protein, minerals and vitamins as shown in Table 2.

Table 2. Suggested Dietary Nutrient Concentrations for Normal and Stressed Calves (dry matter basis).

Nutrient	Nutrient Unit Suggested Range
	Normal (2.8% of BW)	Stressed/Recovery
Dry matter %	80-90	80 - 90
Crude protein %	13.9	12.5 - 17
Net energy for maintenance, Mcal / lb	0.75	0.6 - 0.85
Net energy for gain, Mcal / lb	0.47	0.35 - 0.55
Calcium %	0.5	0.6 - 0.8
Phosphorus %	0.3	0.4 - 0.5
Potassium %	0.6	1.2 - 1.4
Magnesium %	0.1	0.2 - 0.3
Sodium %	0.06 – 0.08	0.2 - 0.3
Copper ppm	10	10 - 15
Iron ppm	100	100 - 200
Manganese ppm	20	40 - 70
Zinc ppm	30	75 - 100
Cobalt ppm	0.1	0.1 - 0.2
Selenium ppm	0.1 – 0.2	0.2 - 0.3
Iodine ppm	0.5	0.3 - 0.6
Vitamin A IU / lb	1000	2,000 - 3,000
Vitamin E IU / lb	7	20 – 50

Source: Adapted with modifications from (2).

Feed Ingredients

Upon arrival, feed starter calves ingredients that are familiar to cattle. Most calves have previously consumed hay; feed soft, palatable grass hay free choice in the bunk upon arrival. Do not feed hay in round bale feeders as this practice teaches calves to stay away from the bunk. The goal is to encourage calves to approach the feed bunk so that feeding personnel can control calf diets and animal performance as soon as possible.

If you feed silage based rations, start calves on your most palatable silage. In general, cereal silage and corn silage are the most palatable types of silage. Relative rankings for silage palatability are as follows; corn silage > cereal > grass silage > alfalfa > clover silage. Assuming a proper fermentation occurs, drier silage is more palatable than wet silage.

In western Canada, barley and oats are the main types of grain used to start calves on feed. Either grain will work fine in calf starter programs as they are both quite palatable.

Bunk management is crucial to the success of any feeding program. During the first 30 days on feed, lightweight calves should be fed several times per day to stimulate feed intake and to keep fresh feed in front of the calves at all times (see Principles of Bunk Management). Freshly weaned calves should remain on a starter program for 3-4 weeks prior to moving to grower rations. The decision to move calves to a grower program is based upon reading the calves. Are they healthy? What is their DMI? What is the weather forecast, etc.?

Water

Water is a crucial ingredient. Calves entering a feedlot for the first time may have never consumed water from a waterer previously. The water must be clean, fresh and always available. Splash the water several times per day during the first week in the pen. If a calf does not drink, the calf will die.

Energy

Calves utilize the energy in the feed, for maintenance and growth. Calves consume most of their energy as carbohydrates that come predominantly from grain. As intake increases above maintenance requirements, performance increases as the added energy goes to growth. Therefore, feed conversions are improved and cost of gain is reduced as gains go higher.

When starting lightweight calves:

• Feed an energy dense diet, i.e. a 45-50% concentrate ration on a dry matter basis. Low energy starter rations may depress the immune system in calves (3), conversely, too high of concentrate levels in a starting diet can lead to acidosis and may result in an increase in morbidity (4).
• Adjust energy concentration in the grower ration to reflect the desired gain of the calf.

The dietary protein content of rations for starter calves should be increased to compensate for low dry matter intake (Table 2). There are three main types of supplemental protein nutritionists use to formulate cattle supplements. The sources are nonprotein nitrogen (NPN or urea), rumen degradable proteins (canola meal, soybean meal) or rumen bypass protein sources such as distillers grains, brewers grains, blood meal or feather meal. Gates (5) found that calves tolerated urea fed at the rate of 30 grams per head during the first 2 weeks of the feeding program. However, other work (6) showed that plant protein is more efficiently utilized than urea by starting calves. Flurarty (7) observed a response to feeding blood meal in starting diets. Other observations have shown the increased performance of cattle fed bypass protein in the starting phase does not necessarily maintain itself during the balance of the feeding period. (8) Further research in protein nutrition for feedlot cattle fed barley based rations would be quite useful to the Canadian cattle feeding industry.

In western Canada, many feedlots will feed a starter supplement with an inclusion rate of 5% of dry matter in the starter ration. Many of these formulations contain 30-35% crude protein, 5-8% of the protein from urea and the balance of the supplemental protein from natural sources. Bypass proteins have the greatest chance of economic viability when fed during the starting phase. Palatability and economics involved with supplementation of various protein sources must be considered. Data has not demonstrated an economic benefit to feeding bypass protein for cattle fed barley based growing and finishing rations.

Macro Minerals

Potassium, calcium, phosphorus, magnesium and sodium are macro minerals that need to be considered in a starting program. Levels to supplement are a function of concentration in your forages and grain as compared to nutrient requirements of the animal:

• Increase the dietary concentrations for these minerals (Table 2) since freshly received calves have low dry matter intakes.
• Stressed calves excrete substantial amounts of potassium and sodium. These minerals are in low reserve in cattle (9) and need to be replenished in a starting ration. Phillips (10) achieved increased performance with boosted potassium levels in the diet of newly arrived calves. Skeletal reserves of calcium, phosphorous and magnesium do occur and calves can partially rely on these reserves when feed intake is low.

Trace minerals and vitamins are involved in the immune response. Trace minerals must be supplemented to cattle as most forages and grains are inadequate in trace minerals. (see Trace Minerals for Backgrounding and Finishing Beef Cattle in this section of the Guide).

• Dry matter intake is low in the initial starting period; therefore dietary trace mineral concentrations should be elevated as compared to levels fed to cattle that are 'on feed'’ Higher trace mineral concentrations may boost the immune system (12).
• Feed trace minerals in the inorganic form (sulfates and oxides) unless previous experience dictates the use of organic trace minerals. Inorganic forms cost significantly less than organic forms of trace minerals. Organic trace minerals have gained favour (13,14) relative to immune function, possibly due to their higher bioavailability than inorganic sources. The bottom line, if traditional sources (inorganic forms of trace minerals) are effective, then formulate your ration with them as their cost is significantly less than the organic forms.

Table 3. Effect of Vitamin E Supplementation on Performance, Morbidity and Mortality in Stressed Cattle.

Item	Control (450 IU/day Vitamin E)	Vitamin E (1,600 IU/ day for 21 days)
Number of head	252	250
Average daily gain, kg	0.43 a	0.53 b
Feed conversion	18.56	15.06
Sick days	3.2	2.7
Morbidity	43.2	37.5
Mortality	1.8	1.6

Adapted from (16).
^a,bMeans with different superscripts differ (P<0.01)

Feed Additives

Ionophores are beneficial in starting and growing rations for feedlot calves. Ionophores provide protection against coccidiosis, improve feed efficiency and stabilize the rumen environment by reducing the incidence of bloat and acidosis. The three ionophores cleared for use in Canadian feedlots are Bovatec®, Posistac® and Rumensin®. Calves started on Rumensin® should be fed 22 ppm (dry matter basis) rather than 33 ppm as the higher level may reduce feed intake. The ionophore of choice depends up your feeding situation and desired results.

Other feed additives such as yeasts and direct-fed microbials may have some benefits (18). However, be sure to base your decision making on these types of feed additives on sound data rather than testimonials. Use of antibiotics should be based on a cost-benefit ratio based on scientific data and a discussion with your veterinarian.

Growing Phase

Once lightweight calves are started on feed and moved to a grower program, their nutritional requirements are a function of environment, size, sex, flesh of the animal and desired performance. With lightweight calves, there is a broad range of options relative to performance. Are your calves going to grass and therefore to gain 1 to 2 lbs. per day? Are your calves being backgrounded for a finishing feedlot at 1.5 to 2.5 lbs. per day. Consider moving your calves directly to a finisher ration, if they have adequate frame, to capture improved feed conversions and to sell the calves into a specific market.

There is a wide range of nutritional programs available to achieve your desired goal. The main requirement in feeding lightweight calves is to have an outcome in mind and be adaptable if economic factors should change. Points to keep in mind, the slower the gain, the higher the feed conversion and the greater the cost of gain. When you have a contract with a finishing feedlot for a set of calves with a range of average daily gain (e.g. 1.5-2.0 pounds/day), always target the highest gain possible to improve feed conversion and reduce the cost of gain.

Practical Considerations

To be competitive in cattle feeding, a scale on your mixer wagon is valuable to ensure accuracy of feed ingredients. In addition, to monitor shrink and animal performance, a cattle scale is crucial to know your cost of gain.

Lightweight calves are not all the same and should not be treated the same. The only similarity may be their body weight. Frame size, body composition, history and potential performance can be vastly different. Consider why the calves are light:

• Are they young?
• Have they been on a low plane of nutrition?
• Were they sick as calves and have never recovered?
• Are they a smaller frame size?

Table 4. Example Grower/Feeder Rations (dry matter basis) and Estimated Gain.

Feed Ingredient	Feeder Ration 0	Feeder Ration 1	Feeder Ration 2	Feeder Ration 3
Barley (%DM basis)	15	25	35	45
Silage (%DM basis)	80	70	60	50
Supplement (%DM basis)	5	5	5	5
Estimated Average Daily Gain (lb/day)1	1.5	1.75	2	2.25

¹Estimates are based on historical performance figures; gain may be above or below these estimates based on genetic and environmental factors.

Summary

Starting calves on feed is critical to the success of feeding light weight calves. Poor eating habits and performance established in the start up phase may carry on through the entire feeding program. The potential of the calf and final market must be understood. There are times when alternative feeding programs are superior to traditional programs.

References

1. Hutcheson, D.P., and N.A. Cole, 1986. Management of transit-stress syndrome in cattle: Nutritional and environmental effect. J. Anim. Sci. 62:555.
2. National Research Council. 1996. Nutrient requirements of Beef Cattle.
3. Nockels, C.F. 1988. The role of vitamins in modulating disease resistance. Vet. Clin. N. Am. Food Anim. Prac. 4:531-542.
4. Lofgreen, G.P., et al. 1980. Effect of dietary energy, free choice alfalfa hay and mass medication on calves subjected to marketing and shipping stresses. J.Anim.Sci.50:590-596.
5. Gates R.N., and L.B. Embry.1975. Soybean meal or urea during feedlot adaptation and adaptation of growing calves. South Dakota Feeders Day Report. 7525:27.
6. Gates R.N., and L.B. Embry.1975. Soybean meal or urea during feedlot adaptation and adaptation of growing calves. South Dakota Feeders Day Report. 7525:27.
7. Flurarty, F.L. and S.C. Loerch. 1992. Effects of protein level and protein source on performance of newly arrived feedlot steers. The Ohio State University Animal Science Series. 92-1, p.57.
8. Gibb, Darryl, 1999. Personal Communication.
9. Macrominerals, Mallinkrodt Feed Ingredients, Mallingkrodt Veterinary Inc. Mundelein, Illinois.
10. Phillips et al. 1986. The effect of a preassembly zeranol implant and posttransit diet on the health and metabolic profile of feeder calves. J. Anim. Sci. 62:27.
11. Nockels, C.F. 1990. Effect of Stress on mineral requirements. In Proceedings of the Eleventh Western Nutrition Conference. 27-31.
12. Spears J. W. et al. 1991. Effects of zinc methionine and zinc oxide on performance, blood characteristics and antibody titre in stressed feeder calves. IAUVMA. 199:12.
13. George, M.H. et al. 1997. Effects of source and amount of zinc, copper, manganese, and cobalt fed to stressed heifers on feedlot performance and immune function. The Professional Animal Scientist 13:84-89.
14. Chirase, N.K. et al.1994. Recovery rate and plasma zinc and copper concentrations for steers calves fed organic and inorganic zinc and manganese sources with or without injectable copper and challenged with infectious bovine rhinotracheitis virus. J. Anim. Sci. 72: 212-219.
15. Kegley, E.B. and J.W. Spears.1994. Bioavailability of feed-grade copper sources (oxide, sulfate and lysine) in growing cattle. J. Anim. Sci. 72:2728-2734.
16. Gill, D.R. et al. 1986. The effect of vitamin E supplementation on the health and performance of newly arrived stocker cattle. OK Agr. Exp. Stn. Res. Rep MP 118:240.
17. Hicks, R.B. 1985. Effect of nutrition, medical treatments and management practices of newly received stocker cattle M.S. Thesis. Oklahoma State University, Stillwater, Oklahoma.
18. Lodge, S. et al. 1996. Use of direct fed microbials to alleviate sub-acute acidosis. 1996 Nebraska Beef Cattle Report: pp. 66-67.
19. Cattle Drive 1998. Investigation of the relationship between days on feed and feedlot production costs in value based marketing systems. Feedlot Health Management Services, Okotoks, AB.
20. McCoy. R. et al. 1996. Effect of energy source and escape protein on receiving and finishing performance and health of calves. 1996 Nebraska Beef Report. p.58.