Applied Swine Nutrition Basics.
Part 1. Theory. Muscle Growth, Ration Energy Density & Ambient Temperature.

Economic Considerations

I want to emphasize that the objective of raising pigs is to earn a profit so your decisions need to be profit oriented. Marginal revenue should be greater than marginal costs. Too often I hear people say, "When I have more money, I will feed my animals better", as if feeding better feed is a consumption item similar to buying jewelry for your wife, rather than looking at good feed as an investment item that will increase your profitability. Ukrainians pride themselves on surviving adversity and too often think that their animals should "tough it out" like Ukrainians have had to do in the past. This is faulty logic that costs you money. Of course it takes adequate capital to feed hogs in the first place. My experiences in Russia suggest that the Soviet mentality considered the objective of being big as more important than being profitable. This is backwards reasoning. I have seen too many operations that had more animals than they had feed to feed them. It seemed logical that they should reduce the number of animals, which would generate revenue to buy feed, and feed the animals that remain, adequately and profitably. If you generate the maximum profit possible from a smaller operation, the profits can finance a larger operation. Farming operations should grow in size from profitability (a free market result) and not from subsidies from central planning so that there is an incentive to allocate resources in such a way as to generate the maximum value for society. Subsidies encourage the misallocation of resources and result in the reduction of a country's gross domestic product. You're on your own raising pigs now so manage for profit.

Livestock feeders should feed their animals properly so that they will have more money rather than getting it backwards and saying that they will feed their animals better when they have more money to buy good feed. Manage for profit and feed good feed.

Management is one of the four factors of production. (1) Management manages (2) land and its resources, (3) labor and (4) capital. The intent of this manuscript is to help you improve your management capabilities so as to create the maximum amount of value from the resources you manage. Your success in doing so is measured by the profit you make. I know that profit was a dirty word during Soviet times, but in a market economy the objective is to earn an honest profit. This encourages managers to manage limited resources to maximize profit, which also maximizes the creation of wealth for a society.

The Importance of Having Clean Fresh Water Available to Animals at All Times!

In any discussion of feeding animals it is important to emphasize the need to have plenty of clean fresh water available, so I'll say it now and we can go on to other things. Remember that if you limit water intake, the animal will limit its intake of feed resulting in more of the feed consumed going for maintenance rather than for production and your income will be reduced. Failure to supply adequate water of good quality to animals is a good way to shoot yourself in your billfold.

Non-Feed Considerations

Some non-feed considerations: Pigs need space to run and play in order to grow optimally. The recommendation (per pig) of the U.S. National Research Council is to have at least 0.41 square meters of floor space for pigs weighing up to 20 kg, 1.06 square meters for pigs weighing from 20 to 50 kg and 1.10 square meters for pigs over 50 kg body weight. Allowing your pigs more space is OK, although unnecessary activity isn't free as it uses up energy that you'd prefer the pig used for the production of pork. Remember that you're interested in the put-through of your facilities. Manage so as to maximize your profit per day for the facility and per pig/day rather than focusing solely on the profit per pig or per kilogram of gain. Manage for maximum return on investment.

You need to consider both (1) feed (usually 80% of total costs) and (2) non-feed costs (20%) of fattening pigs in making management decisions. Time may not matter much to a hog but it is important to you so in making management decisions consider the number of days it takes a hog to get to market. Some feed combinations may show more income over feed costs than other options but this economic advantage can be eroded and lost if daily non-feed costs are greater for slower growing pigs than the feed cost savings. We'll look at this when we discuss the Pig Profit Planner computer model (Part 3) I developed to help you answer the important questions of (1) "How much money can I expect to earn (or lose) by feeding pigs" and (2) "Which feedstuff (energy & protein source) combinations will make me the most money?" Estimate your profit and loss before you start feeding pigs (called a budget) and don't feed pigs if you expect to lose money. Be a smart capitalist so that you'll have enough money to play the hog raising game tomorrow, which means you must be concerned with the preservation of capital today. Don't waste capital by knowingly going into a money losing hog feeding operation. The Pig Profit Planner is presented in Part 3 as it uses theory (Part 1) and formulations (Part 2).

Ideal Ambient Temperature and Effects of Temperatures Below and Above Ideal �C

It is economically important to take the ambient temperature into consideration when formulating diets for growing pigs.

The ideal ambient temperature for a growing pig can be determined by the formula,

Formula #1: 26 �C - (0.0614 times kg body weight)

For example, the ideal ambient temperature for a 50 kg pig is:

26 �C - (0.0614 x 50) = 26 - 3.07 = 22.93 �C.

The following table gives the ideal temperature for hogs of selected weights:

Table 1: �C Ideal Ambient Temperature for Various Weights of Growing Pigs, Kg.

The ideal ambient temperature can be referred to as the center of the zone of thermal neutrality (which is fairly narrow). Variations from this temperature, either hotter or colder, affect the performance of the pig. You can see that the ideal ambient temperature decreases as the pig gains weight. Small pigs need to be kept warm.

(The ideal ambient temperature for gestating and lactating sows is considered to be 20 �C. Adjusting the ration requirements of sows for ambient temperatures different from 20 �C is the subject for another paper, so expect to hear from me again.)

There is another handy formula that you need to know that is used for predicting energy intake at temperatures different from the ideal ambient temperature. If you subtract the actual �C ambient temperature (AT) from the optimum temperature (OT) (calculated by the above equation) and multiply this number times 0.0165 it will approximate the change in voluntary energy intake from that consumed at the ideal temperature.

Formula #2: Change in Feed Intake = (OT - AT) x 0.0165

For example when the ambient temperature is ten degrees centigrade less than the ideal temperature, pigs will eat 16.5% more feed at the colder temperature (1.65% more feed per each one �C below the ideal temperature). If it is 10 �C above the ideal temperature, the pig will eat 16.5% less feed. (The feed intake prediction equation works only when applied to the ideal temperature as multiplying 1.65% times the intake at a temperature different than the ideal ambient temperature will overestimate feed intake below the ideal temperature and underestimate it above the ideal temperature because the base amount of feed intake used in the formula is different at temperatures other than the ideal temperature.)

The important concept to understand is that pigs adjust their energy intake voluntarily to match their need to maintain body temperature by eating more feed when the ambient temperature is below the ideal temperature and less feed if it is hotter than ideal.

Here is a table that does the math for you. It shows the percent change in energy intake by pigs of different weights fed in different ambient temperatures.

(1) Ideal �C Ambient Temperatures for Pigs of Different Weights
(2) Percent Change in Average Daily Energy Intake from Ideal �C at Various Ambient �C

Pig	Ideal	Average of High & Low Daily Ambient Temperatures that Pig Experiences. Not Temperatures Outside Hog House.
Weight	Ambient	0 �C	5 �C	10 �C	15 �C	20 �C	25 �C	30 �C	35 �C
Kg	�C	Percent Change in Energy (Feed) Intake Due to Differences in the �C Ambient Temperature from the Ideal �C Temperature
10	25.39	42	34	25	17	9	1	-8	-16
20	24.77	41	33	24	16	8	0	-9	-17
40	23.54	39	31	22	14	6	-2	-11	-19
60	22.32	37	29	20	12	4	-4	-13	-21
80	21.09	35	27	18	10	2	-6	-15	-23
100	19.86	33	25	16	8	0	-8	-17	-25
120	18.63	31	22	14	6	-2	-11	-19	-27
140	17.40	29	20	12	4	-4	-13	-21	-29

Feed intake is also influenced by the energy density of the ration. As the fiber level of the ration goes up, the energy level of the ration is diluted and pigs eat more feed to compensate for the lower energy content of the feed up to about ten or perhaps even 15% crude fiber. The digestive tract of the pig cannot process more than 10% (or perhaps a maximum of 15%) crude fiber without the pig reducing feed intake. A hay baler can process only so much hay. The same is true for the pig's digestive tract. Pigs cannot compensate for low energy intake by increasing feed intake of rations that contain fiber levels above these critical levels and thus hog growth performance is reduced.

We've talked a lot about protein and energy. The following table looks at the protein and lysine levels (to be used in a later discussion) and various energy measurements of protein sources and energy sources. Notice the low energy content, particularly net energy, of sunflower meal with hulls and wheat bran.

Digestible energy is gross energy of the feed less energy lost in the feces. Metabolizable energy is gross energy less energy lost in the feces, urine and digestive gases. Net Energy subtracts the heat increment from metabolizable energy. Heat increment is the amount of energy (heat) released from digestive and metabolic processes. Net energy is the energy that the animal has available for maintenance and production. Net energy is difficult to measure but is the best indicator of the amount of energy available to the animal for maintenance and production.

The amount of net energy used for maintenance is influenced by the ambient temperature and the energy used by the pig for physical activity.