3. Protein
a. Expressed as crude protein (CP) or metabolizable protein (MP)
- difference between the two is the early phases of calf feeding program
- MP suggests higher levels of protein at lighter body weights
- Both systems are similar for heavier cattle
b. Protein is expensive but a deficiency is more expensive than a slight exces because if a deficiancy occurs then energy will not be optimally utilized.
c. Protein can be natural or NPN
d. NPN best when:
(1) ration contains a high percentage of readily fermentable CHO
(2) Soluble N levels of the ration are fairly low
(3) Cattle being fed the ration have a relatively low protein requirement
e. NPN least utilized when fed to:
(1) young calves which have a high protein requirement
(2) calves that have been under stress and in transit (microbes)
(3) beef cows grazing on all range forage ration
(4) cattle consuming rations with high level of soluble N (legumes)
III. Miscellaneous Finishing Ration Ingredients
A. Minerals
1. Calcium - Generally adequate if the ration is 25% or greater forage (esp. legumes)
- Try to maintain 2:1 or higher CaP to prevent urinary calculi in feedlot steers (.5% NH4Cl or NH4SO4)
2. Phosphorus Deficiency unlikely on high concentrate diet, usually associated with feeds grown on P-def. soils
3. Salt Requirement of full-fed beef cattle met by including .25% in the total ration
4. Potassium
- Diets high in forage are generally adequate in K
- Cattle on high concentrate diets usually require K
- K requirement of stressed claves may be 2 X normal
5. Sulfur
- Been shown to be beneficial if NPN is used (S A.A.)
-Maintain a 10:1 urea N:S ratio
6. Trace Minerals
a. Geographic Problems
b. Magnesium and grass tetany
(1) Caused by ¯ serum levels of Magnesium (Mg)
(2) Occurs rapidly in lactating cows allowed lush pasture after over-wintering
- low Mg, high K, N ==> limited Mg absorption
- brought on by excitement, milking, transport, adverse weather
(3) Syptoms
- severe paddling
- tetany
(4) Prevention
- Mg supplements
(5) Treatment
- IV Mg and Ca
- sometimes sedatives
- MgSO4 enema
B. Vitamins
- many synthesized by rumen microbes and many inthe ration
- may need A,D,K
C. Ionophores
Improve feed efficiency, ¯ intake, tends to ADG
1. Rumensin (monensin)
2. Bovatec (lasalocid)