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Farm Forum

September 2003

In This Issue

• Market News
• Calendar
• Looking Down the Road
• Countdown to Silage Harvest
• CIDR Estrus Synchronization Approval
• Pre-Treating Heifers
• Program Cost Recovery
• Milk Production and Feed Intake

Announced on September 1st, the August Class III (cheese) price was $13.80, up approximately $2 from the previous month. This compared to the July 2002 Class III of $9.33. Announced on September 1st, the August Class IV (butter/powder) price was $10.14, up another 19 cents from last month. This is down 27 cents compared to last year's Class IV of $10.41. Announced on August 22, 2003, the September Class I (fluid milk) price was $13.71, up $2.74 from last month. This compares to a September 2002 Class I mover of $10.46.

Joel Hunter CCA (Crawford County, Agronomy) wrote:

I have scheduled two pesticide update field days for September. (It seems some folks are looking for credits to keep their license.) The plots consist of fifteen competitive herbicide programs in corn (randomized and replicated three times) and including Roundup Ready technology.

The first will be held on Tuesday, September 23, 2003 at the Ken Hyde Farm just out of Titusville. Location: 10842 East Troy Road...turn right onto East Troy off Route 27 just a few miles west of Titusville (nearly across from the airport).

The second will be held on Thursday, September 25, 2003 at with cooperator Jim Davis near Spartansburg. Location: Sundback Road...south east of Spartansburg...follow Grade Road (dirt road straight off Rte. 77 at Wild Horse Saloon) or take South Spring Street out of Spartansburg Blakeslee.

I will try to put some directional signs up at strategic locations. Both meetings will consist of an hour on the plots (1:15 to 2:15 pm) for 2 category credits followed by an hour (2:30 to 3:30 pm) for 2 core credits. For more information contact the Crawford County Cooperative Extension office at (814) 333-7460.

It seems like in the dairy industry parity always prevails. Looking down the road it is easy to conclude that recent gains in milk price will likely be off set by this summer's wet growing conditions and the affects it has had on forage inventories and quality. There should be no doubt that producers will be scrambling in the weeks to come to at least salvage what is left of this year's growing season. Yes, there will be a lot of corn silage made. Some from corn planted on time and for that intended purpose and a lot from corn planted late, poorly eared, likely frost damaged and probably not of forage varieties. For those of you who are intimidated by the idea of feeding a diet whose forage source is nearly or completely all corn silage, there is hope but it takes careful planning. Issues to consider are particle size (length of cut), kernel processing, plant moisture levels and cutting height (see the following article by Greg Roth). What you end up with may not be what you planned, but at least it beats a bare pantry. In terms of the final product, do not take anything for granted. When it comes to high corn silage diets, the old adage "You can't manage what you don't measure "applies. Plan on taking a number of complete forage analyses throughout the year. In addition to the basics, lignin levels, starch levels, some estimate of the NFC and a fermentation analysis should be part of the testing. It is also important to get some estimate of the physically effective (Pe) NDF and the level of "fines" in the corn silage. This requires the use of a 4 tier Penn State shaker box. When the finished ration is delivered to the cows, monitoring milk components, cud chewing, dry matter intakes, and free choice bicarb consumption are important parts of detecting any potential problems. In some circumstances, measuring manure starch levels may be necessary for fine tuning. Toward the end of October we are planning at least two barn meetings in the region devoted to the nutritional challenges created by this years growing conditions. Watch for a separate Cooperative Extension mailing later this month.

On many dairy farms corn silage harvest will begin in the next few weeks. Since corn silage is the foundation for many dairy rations, it's important to manage the crop to maximize the quality of forage that is preserved. This is especially important this year since the quality of much of our hay crop silages is less than ideal. Consider these points during silage harvest this year:

Chop at the right moisture content for your silo. Measure crop moistures to be sure. This year crop maturity will likely be delayed. Start monitoring crop moistures prior to harvest- then estimate harvest with a dry-down rate of 0.5%/day. This gets everyone thinking about silage harvest ahead of time.

Consider the harvest height in your silage harvest. Harvesting one foot higher reduces yields about 8-10%, but increases the energy content and fiber digestibility and also results in forage that is about 2% drier. This could be an advantage in some situations and allow for a 3-4 day earlier start to the harvest.

Monitor particle size during harvest. For processed corn silage, start with a ¾ inch theoretical length of cut (TLC) and 1-3 mm roller clearance. Do not chop processed silage too fine. For unprocessed silage shoot for 3/8 to 3/4 inch TLC with a finer cut on drier silage. Ideally, monitor particle size distribution during harvest with a Penn State Particle Separator.

Monitor cob and kernels in processed silage. Cobs should be broken into 1/8 concentric rings and kernels should be broken in several pieces.

Pack bunker silos thoroughly. University of Wisconsin Ag engineers suggests a rough target of 800 pound of packing tractor for every ton/hr that silage is delivered to the silo. So a 40 ton/hr delivery rate would translate into 32,000 pound tractor requirement. Silage moisture, chop length and the depth of spreading the silage can influence this requirement- some folks seem to get by with lower weight tractors.

Try to fill rapidly and continuously and then cover the silo with plastic immediately. Weight the plastic with tires or split tires or sidewalls laid down end to end. The split tires are gaining in popularity and have several advantages: easier to handle, less habitat for mosquitoes and rodents and are just as effective.

Consider segregating early and late-planted silage crops if it helps with ration formulation. Later planted, lower grain silage could be targeted for heifers and other livestock with lower energy requirements.

The Controlled Internal Drug Release (CIDR) device, which releases natural progesterone to synchronize estrus, was approved in 2002 for use in dairy heifers and beef cattle. Use of the CIDR insert for the prescribed seven days in combination with an injection of prostaglandin (PG) on day 6 or 7 has been effective in synchronizing estrus in heifers. Recent data reported in the Journal of Dairy Science (Chenault et al. June, 2003) showed the concentrations of progesterone in milk due to the presence of the CIDR vaginal insert were significantly less than concentrations of progesterone in milk from pregnant cows. It was concluded that milk from cows administered a CIDR insert was safe for human consumption. For many years this system has been used in New Zealand for synchronizing estrus in lactating cows and in August 2003 it was approved in the United States for lactating dairy cows.

During the last fifteen years or so considerable research has been conducted on various applications of this reproductive management tool. One application is to integrate the CIRD into the Ovsynch program. Research has shown that inserting a CIDR on the first day of the Ovsynch program, removing it on day 7 when PG is administered and continuing with the standard Ovsynch protocol improved conception rates compared to the standard Ovsynch program without use of a CIDR, especially in high producing cows that were anestrous. Other systems using the CIDR are currently being tested.

Another application is to use the CIDR to increase post breeding heat detection rate for open cows following a previous insemination. This concept is termed "Resynch". Using this approach recent research demonstrated that inserting a CIDR on day 14+/- 1-day post insemination and removing it seven days later improved the heat detection rate compared to cows visually observed for estrus without use of a CIDR. More cows were observed in estrus 2 to 5 days after removal of the CIDR than control cows during a 9-day period of expected return heats. To benefit from this system heat detection must be frequent and routine. Thus labor can be focused on certain days to improve post breeding heat detection on a group of previously synchronized and inseminated cows so the interval to rebreeding is reduced. This is just another tool in a systematic approach to reproductive management.

Caution: do not use PG in this Resynch program, as PG will induce embryonic death in the pregnancy cows within this group.

Discuss these different strategies with your veterinarian and other members of your management team to determine if they can enhance the reproductive performance of the herd.

Many studies have been conducted on pre-treating heifers prior to freshening suggesting that it can be both effective and economical.
A recent study at the University of Tennessee reported in the April Journal of Dairy Science, suggests that heifers treated with an intra-mammary antibiotic formulation prior to calving produced almost 1,200 pounds more milk than untreated heifers.

Milk samples from the quarters of untreated heifers and from quarters of heifers treated with a lactating cow antibiotic formulation at seven or fourteen days prior to expected calving were collected by researchers during the study.

Milk samples from untreated heifers contained significantly more mastitis pathogens than milk samples obtained from the antibiotic treated heifers. Researchers were able to isolate mastitis pathogens from 47 percent of the milk samples of the untreated heifers three days after calving, but researches found only eight percent of the samples from antibiotic treated heifers three days after calving contained mastitis pathogens.

Ten days post calving, the untreated heifers showed twenty-nine percent of the sampled animals contained mastitis pathogens, while only four percent of the treated animal samples showed mastitis pathogens. During the remainder of the lactation, thirty percent of the untreated heifers still contained mastitis pathogen, while the treated heifers had a rate of mastitis pathogens of eleven percent. Milk from the treated heifers also had a lower somatic cell score than that of the untreated heifers.

With an increase of nearly 1,200 pounds of milk by pre-treating heifers, it looks like there is an economic benefit to producers even with the cost of treatment and labor. With a milk price of ten dollars per hundredweight and a heifer producing 1,200 pounds of milk, she will earn nearly $120. With treatment costs of over fifteen dollars which includes the cost of testing for antibiotics, and a labor cost of ten dollars per heifer, a producer could gain around $95 per heifer during the initial lactation. So, according to the Tennessee study, it does pay to pre-treat heifers before first lactation with an intra-mammary antibiotic formulation.

For the most part all the good things in life are free and that applies to many Cooperative Extension Programs. Unfortunately, with recent budget cuts, some selective services requiring specialized equipment and/or software not supported by the University will likely be done on a fee basis in the near future. These include ration balancing using computer rumen simulation models and milking system evaluation when investigating issues of milk quality. Money generated will be used to support the equipment, software, and training required to run them. It is our intention to set fees as low as possible and on a voluntary basis. Penn State Cooperative Extension programs are open to all, regardless of their ability to pay. Please contact us if you require reduced or waiver of fees to attend a program or use a service.

Eighty-four Holstein cows were utilized to evaluate effects of dry period (60 d vs. 30 d), with or without estradiol cypionate (ECP) injections to accelerate mammary involution, on prepartum and postpartum dry matter intake (DMI), body weight (BW), body condition score (BCS), and subsequent milk yield (MY). Treatments were arranged in a 3 x 2 x 2 factorial design that included dry period (30 d dry, 30 d dry + ECP, and 60 d dry), prepartum and postpartum bovine somatotropin (bST; 10.2 mg/d), and prepartum anionic or cationic diets. To accelerate mammary involution, ECP (15 mg) was injected intramuscularly at dry-off. No interaction of bST or prepartum diet with dry period length was detected on BW, BCS, or MY. No significant effects of dry period length on prepartum DMI, BW, or BCS were detected. Cows with shorter dry periods maintain postpartum BCS better and tended to have greater DMI immediately postpartum. Mean daily yields of milk for dry period groups did not differ during overall lactation period (1 to 21 wk). Injection of ECP at the onset of the 30-d dry period did not affect MY. No significant differences due to dry period length were detected for milk, 3.5% FCM, or SCM yields during first 10 wk of lactation. Data indicated that a short dry period protocol can be used as a management tool with no loss in the subsequent milk production of dairy cows.

J. Dairy Sci. 2003. 86:2030-2038

Sincerely,

Nelson Smith
Extension Educator, Dairy/Ag

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