The dairy industry is flocking to Texas, especially the Panhandle. Currently, in the Texas High Plains there are 234,000 milk-producing cows. In Texas the number of dairy cattle have greatly increased in the northern High Plains from 6,000 head in 2000 to over 185,000 head in 2010.

The size of dairies by number of head is also rapidly changing in Texas, especially herds that have over 500 lactating milk cows. In 2000, only 7 percent of Texas dairies had a 500-plus milking herd; however, this 7 percent accounted for 48 percent of the total milk produced in Texas in 2000.

The number of dairies with 500-plus cows per herd in Texas jumped to 15 percent in 2007 and accounted for 84 percent of total milk produced in Texas. The increase in the number of cattle per dairy means greater quantities of feed will be needed to support the growing industry.

Silage is a crucial component for dairy rations. Silage, unlike grains, must be produced locally. It is difficult for a dairy producer to have enough land, not only for his dairy operation, but to grow feed for his entire herd. Many dairies rely on neighboring farms for silage to meet feed requirements for their herds.

The average lactating dairy cow needs approximately 90 pounds of feed per day. This feed must possess adequate protein and be easy for cattle to digest, relatively inexpensive and readily available. A major component of rations for dairy cows is corn silage.

West Texas is a top choice for dairies because the environments are desirable for dairies and the irrigated environments are ideal for corn production. An increase in the number of dairies relocating to Texas benefits not only the local economy but also area corn producers.

Corn silage production in the Texas High Plains varies between the northern and southern High Plains. (See Figure 1.)

In 2000 the northern High Plains produced 1,422,000 tons of corn silage, compared to the southern High Plains, which produced 275,000 tons of corn silage.

By 2008, the northern High Plains corn silage production had grown to 2,447,800 tons, and the southern High Plains produced 489,500 tons of corn silage.

With the rapid increase in the number of dairy cows in West Texas, it is expected corn silage would keep pace. However, the two are hardly keeping pace with each other.

Corn silage production has increased by 1.7-fold in the northern High Plains and the southern High Plains from 2000 to 2008. While the number of dairy cows has increased 30-fold in the past 10 years in the northern High Plains and four-fold in the southern High Plains.

A possible misconception is that corn silage and dairies are not strongly related, when in reality there should be a strong, positive correlation between the two.

This increase in the number of dairy cows in the Texas High Plains has also led to a dramatic increase in state milk production. Texas northern High Plains milk production has increased precipitously from 1.79 million pounds of milk in 2000 to 385.5 million pounds of milk in 2009 (an increase of 215-fold).

Southern High Plains milk production has also increased from 2.1 million pounds to 115.4 million pounds for a 55-fold increase in the past nine years.

Review of literature

A dairy has several options for feedstuffs to maintain a herd. Corn silage has on average 8.5 percent crude protein and 3.8 percent lignin; alfalfa silage has 20.8 percent crude protein and 8.3 percent lignin.

A study was conducted comparing three feeding treatments (corn silage, corn silage + alfalfa silage and corn silage + alfalfa hay) fed to 54 Holstein cows. The study concluded the highest milk yield trend was achieved when cows were fed corn silage + alfalfa silage or hay treatments.

The corn hybrid selected by the producer also is important. A hybrid that is a great grain product may not provide optimal milk production. There are several traits hybrids can possess to increase their attractiveness to producers.

Brown-midrib (BMR) is a homozygous recessive trait that reduces the lignin content of the corn silage and increases digestibility by improving neutral detergent fiber. However, BMR yield tends to be lower than conventional hybrids.

Leafiness is another agronomic corn trait that increases the number of leaves above the ear. Plants expressing this trait also have been reported as having softer kernel texture and higher grain moisture content, thus making the leafy hybrids more desirable to dairy cows.

Researchers fed conventional hybrids at high and low plant population, and leafy hybrids at high and low plant populations, to 24 Holstein dairy cows. They found total milk production was not significantly different among the four treatments; however, the plant population was statistically significant when looking at crude protein content. Crude protein content was higher in the high-plant population treatments, both in leafy and conventional hybrids.

The hybrid selection process also needs to take into consideration soil fertility needs and water requirements. The nutrient requirements of corn silage production are higher than corn grain because, in silage production, the entire plant is harvested and removed from the field.

Conversely, in grain production only the grain is harvested. Grain production leaves plant residues on the soil surface, thus adding organic matter and recycling nutrients into the soil. Applying the correct amount of nutrients to the soil is crucial in achieving optimum silage yield. Starting off with an accurate soil test from a reputable lab is the first step.

Dairy manure can be an inexpensive source of fertilizer, but should be analyzed prior to application. Careful consideration needs to be given to the prevention of phosphorous buildup in the soil. Researchers reported that applying manure can have a positive effect by synchronizing N release to early grain filling stage of corn.

Researchers applied low and high-quality dairy composted manure at 3 incorporation rates (0, 20.1 and 40.2 tons per acre) to determine their effect on corn silage yields and forage quality. High-quality compost was defined as having a four-fold increase in organic matter content when compared with low-quality compost.

The authors concluded there was no advantage to using high-quality compost over low-quality compost when looking at silage yields and forage quality. The corn silage crude protein content did not differ among high-quality or low-quality dairy compost manure.

Milk producers might question the value of utilizing hybrids expressing transgenic traits such as herbicide tolerance. Silage performance can be improved by eliminating weeds that compete with corn for light, nutrients, and water.

A team conducted a study to evaluate the impact of glyphosate applications on corn growth and yield. They reported that leaf area index, kernels per plant and grain yield increased when glyphosate applications were made at V3-V4 growth stage. Higher yields would potentially improve silage quality and reduce the number of acres a dairy would contract to satisfy silage demands for the herd.

Future directions

Increasing milk production per ton of silage fed may help dairies achieve profits needed to stay in business as profit margins shrink. Hybrid selection is a major decision silage producers can make. Use of a locally adapted hybrid with high tonnage and quality is important for milk production and water conservation.

Brown mid-rib hybrids offer a significant improvement in milk production per ton of silage fed when compared to conventional silage hybrids. However, BMR hybrids yield less than conventional hybrids, requiring dairies to acquire more land for silage or contract more acres to satisfy the needs of their herds. Research is needed to improve yield performance of BMR hybrids without sacrificing quality of the silage.

Another issue confronting Texas High Plains corn producers and dairy producers is the depletion of the Ogallala aquifer, the primary source of water for irrigation. Corn hybrids with improved drought tolerance will be essential to meet the needs of Texas High Plains dairies.

The volatility of fertilizer prices increases the necessity for efficient utilization of nitrogen. Effluent and manure are excellent and relatively inexpensive sources of nitrogen, but over-application can present issues with buildup of certain salts and phosphorus.

Processes to reduce salt and phosphorus levels without affecting nitrogen availability need to be explored. Other avenues to alleviate excessive fertilizer prices include improving the timing and number of fertilizer applications throughout the season, and improving nitrogen use efficiency in the plant.

Additional research needs to be conducted to determine if the Texas High Plains can provide corn silage for all the dairies relocating to West Texas and the possible economic benefits. It would also be interesting to see exactly how much feed is being brought into the Texas High Plains to provide for dairies, and to see if the area is capable of supporting that growth. PD

References omitted due to space but are available upon request to editor@progressivedairy.com.