Focusing on your pre-weaned calves, here are some basics to follow for improved calf health and growth during hot weather.
First, it’s important to recognize that your calves tolerate slightly higher daytime temperatures than your cows, with stress beginning when the temperature is over 80o F (26oC).
Encourage Food Intake
Calves born in hot summer months have lower average daily gains versus those born in other seasons (Bateman & Hill, Progressive Dairyman, 2012). Reduced average daily gain means a delay in time to puberty, longer interval to first calving and ultimately delayed return on investment. One way to encourage intake, gain and rumen development in your calves is by making fresh starter feed available. Starter intake is also directly related to water intake.
“Like people, your calves’ appetites are reduced during periods of heat stress.”
Drink Plenty of Water
Fresh, clean and abundant water helps to cool calves and is crucial during periods of heat stress, especially for calves with scours. During ideal temperatures calves that are 1-2 months old consume 0.5 - 2.0 gallons of water per day. That amount increases exponentially with heat and humidity and can reach up to 6 gallons per day in young calves.
Rinsing water buckets daily and frequent refills are also advisable. If your calves habitually spill their water, then wire or cable tie bucket handles to holders.
Supplement as Needed
Like scours, heat stress can lead to dehydration. Pay close attention to each calf’s attitude and ability to suckle. Oral electrolyte solutions, like NuLife® Oral Electrolytes, can help replenish fluids. The amount to use depends on the level of dehydration and the ambient temperature. For example, a 100-pound calf that only has a weak suckle may be 5% dehydrated. At normal outdoor temperatures, this calf would require 2.5 quarts of electrolyte solution per day. However, if the outdoor temperature is over 100oF (38oC), the amount should be doubled to 5 quarts per day in addition to normal feedings of milk or replacer (Bentley, Iowa State University Extension).
Provide Air Movement
Air movement promotes cooling; in fact, calves in a curtain sidewall barn showed a 23% increase in average daily gain when cooled with fans (Hill et al, Journal of Dairy Science, 2011).
Air movement also helps your calves by reducing the bacterial load and reducing noxious gases like ammonia in the air.
Recommendations for airflow are over six times higher in hot summer weather than in winter. Your local extension specialist or veterinarian may be able to help you determine if airflow in your calf facility is adequate for summer heat.
For calf hutches, a simple way to improve air flow is to raise the rear of the hutch (can be supported with a cement block). For maximum airflow in hutches place them 4 feet apart with 10 feet between rows.
Block out Direct Sun
No matter the type of housing, your calf needs to be able to get out of direct sunlight. A shade cloth above hutches can reduce the temperature inside the hutch by 3-4 degrees, and therefore reduce body temperature. Calves housed in barns need the ability to move out of sunlight coming through sidewalls or windows. Calves in group housing will “bunch” to move away from direct sunlight or flies, thereby limiting their individual air flow.
Keep Bedding Dry & Combat Flies
Expending energy to swat flies adds to the detriment of heat stress, so use fly control products. Also, fly eggs need moisture to hatch; therefore, use of dry inorganic bedding helps limit flies in the calf rearing area. Having four or more inches of gravel below the bedded surface of hutches or pens helps to drain the fluids away too.
“Expending energy to swat at flies adds to the detriment of heat stress.”
Keep the area under feed and water buckets clean and dry to reduce hatching of maggots. Finally, trimming weeds around calf housing improves ventilation and reduces moisture in the soil.
In summary, you can reduce heat stress in calves to improve their health and your farm’s profitability by following these simple steps in summer months:
› Provide fresh starter daily
› Offer large amounts of clean water
› Provide electrolyte therapy to dehydrated calves as needed
› Produce adequate air flow
› Furnish shade
› Supply dry bedding
› Undertake fly control measures
Mastitis can have a large economic impact on your bottom line. Research indicates the direct and indirect costs – veterinary costs, discarded milk, extra labor, cow mortality, repeat cases and milk losses – amount to $1.7-$2 billion per year.1
Preventive protocols are the best option to curb 50-60% of all new cases that occur during the dry period.2 Dry cow antibiotic therapy has been the most widely used method until recently. With the movement to reduce antibiotic use and regulations preventing organic dairy farms to use dry cow antibiotic therapy, teat sealants have been added to protocols or even used exclusively.
Why add a teat sealant to a dry cow antibiotic therapy?
Understanding the three physical barriers of a cow’s mammary system and with the three stages of the dry period can help you make a fact-based decision on whether to add a teat sealant to a dry cow protocol.
The streak canal, teat sphincter and keratin plug make up the three physical barriers that block or absorb bacteria that may penetrate a cow’s mammary system.
The streak canal is the primary line of defense. The streak canal has its own built-in defense mechanisms, such as physical closing of the entryway into the gland and the formation of a keratin plug to prevent entry of bacteria.
The teat sphincter, located in the teat wall, extends 2mm into the canal. It has no antibacterial activity, but rather contracts and shuts off the streak canal to create a physical obstruction to bacteria. Genetics can play a role in how quickly and tightly this smooth muscle closes off after milking. Clinical and subclinical milk fever can also impact time of closure, as low calcium and magnesium levels affect smooth muscle contraction.
The keratin plug is a mesh-like substance formed by desquamated epithelial cells, fatty acids and cationic proteins. It functions as a physical obstruction and can also absorb bacteria. However, certain bacteria can survive and grow in the keratin plug. It is bactericidal and bacteriostatic. It contains proteins that bind to and cause disintegration of gram-positive bacterial cell walls as well as compounds that inhibit the growth of bacteria.3 It is interesting to note that the fatty acid composition of the keratin plug is heritable.
Understanding the stages of the dry period
The first stage is involution; it starts when daily milking stops. The udder reduces activity and gets smaller, and the keratin plug forms. However, sometimes plug formation is delayed or never happens: 50% of quarters fail to form a keratin plug 7-10 days after dry off, and 10‑23% of quarters fail to form a keratin plug 42-50 days after dry off.4
During the steady stage there are no secretions of any kind. This allows the mammary system to recover and prepare for maximum production. Shortening the dry period two weeks reduces future production. This is a lower-risk stage when it comes to new infections.
The final stage of the dry period is colostrogenesis. This is when colostrum production and the start of lactation occurs. This period lasts around two weeks. New infections are likely to occur during this stage because 1) dry cow therapy is at a level below minimum inhibitory concentration; 2) the cow has a suppressed immune system; and 3) the keratin plug may break down or was never formed during involution.
The real question is did she or didn’t she form a keratin plug? Unless every udder is x-rayed at dry off, there is no way of knowing if she formed a keratin plug. It is known, however, that the keratin plug plays a vital role in killing bacteria already present in the streak canal at dry off and blocking any new bacteria from entering the streak canal.
Will a teat sealant make the difference?
When a teat sealant is deposited in the lower portion of the steak canal, it instantly mimics the keratin plug and seals off the teat for the entire dry period, blocking bacteria from entering the mammary system via the teat canal. It remains in the streak canal until it is manually stripped from the teat or a calf suckles the teat. Studies have shown the efficacy of a teat sealant used in conjunction with antibiotic dry cow therapy can reduce new dry cow infections at calving by 25%.5
What to look for in a teat sealant
Most internal teat sealants have the same key ingredients: bismuth subnitrate (a heavy metal) and a mineral oil base (viscous paste). The manufacturing process, type of tube used to administer the product and where it is manufactured sets the GENEX UdderLife™ OptiShield™ teat sealant apart from other brands.
The type of tube and manufacturing process make all the difference when it comes to keeping the teat sealant in the lower part of the streak canal. If there is an excess amount of air in the tube, it can push the teat sealant further up into the streak canal and lower mammary system requiring extra time for the teat sealant to completely clear. Teat sealants can clog milk filters and interfere with electronic switches in milking equipment.
Tubes with a tip that allow for a choice of full or partial insertion can push teat sealants up too far in the teat canal and require additional training for compliance and consistency. Udder edema can also push the teat sealant above the streak canal and take longer to strip out.
The unique manufacturing process of UdderLife™ OptiShield™ teat sealant prevents large amounts of air in each tube. The tube design allows any additional air to escape during administration, so the teat sealant stays in the lower portion of the streak canal. The tubes are also partial insertion only, removing confusion at administration and providing a more consistent delivery.
Furthermore, most teat sealants are made overseas, which can present the challenge of waiting on a backordered product or the product not being available at all. UdderLife™ OptiShield™ teat sealant is manufactured in the USA.
Teat sealants are another tool to help cows block new dry cow mastitis cases. When considering any new dry cow therapy, it is best to consult with a team of professionals.
If adding a teat sealant to dry cow therapy, UdderLife™ OptiShield™ teat sealant from GENEX can help seal off those profit-robbing new cases of mastitis.
Help your cows block intramammary infections throughout the dry period with the new UdderLife™ OptiShield™ teat sealant from GENEX. This sterile, antibiotic-free, off-white paste contains 62% bismuth subnitrate in a mineral oil base. While it does not treat clinical or subclinical cases of mastitis already present in a dry cow's mammary system, it does help prevent new cases by serving as a malleable barrier in the teat canal, much like a cow's own keratin plug.
Unlike other teat sealants, this product comes with additional benefits:
› The tube contains minimal air, forming a solid plug seal in the teat’s streak canal.
› The partial insertion tip allows for consistent application and less risk of placing the tip too far inside the teat.
› It’s made in the USA! It’s shipped directly to you from the manufacturing plant located in the USA. There are no backorders or wait times!
As with any product, following proper application procedures are important for best results. Watch as Kim Egan, DVM, explains how you should apply UdderLife™ OptiShield™ teat sealant.
UdderLife™ OptiShield™ teat sealant comes in a 4g tube with 144 tubes per pail – that’s enough to administer to 36 cows. For more information, contact your local GENEX representative or call 888.333.1783.
Today, you have more sexed semen product options than ever before and that means determining the most appropriate sexed semen product to use has become more difficult with their differing fertility and price. So, how can you be sure you’ve chosen the sexed semen that will earn you the largest return on investment? Use the Prospective℠ program, a semen profit comparison tool.
The Prospective℠ program is a free, value-added tool aimed at helping you develop the most effective strategic breeding program. The unbiased, Microsoft Excel-based program uses your dairy's basic inputs to calculate how a semen product choice may impact your profits. It shows the return on investment for sexed semen products in comparison to conventional semen.
The program is applicable whether you want to use sexed semen on cows or heifers; the Excel file contains one tab with appropriate calculations for sexed semen use in cows and a separate tab for calculations relating to sexed semen use in heifers.
» For cows, return on investment is calculated as: Difference in Asset (Calf) Value + Difference in Semen Cost + Cost of Added Days Open = Total Profit/Loss of Using the Sexed Product Versus Conventional Semen.
» The same formula is used for heifers, but it also includes a value for additional milk income associated with heifers birthing heifer calves.
Furthermore, the Prospective℠ program calculates the estimated cost of days open based on different breeding strategies (i.e., if you plan to use the sexed semen product on the first service, first two services or all services).
Both the cow and heifer reports are broken into three sections: 1) conventional semen, 2) GenChoice™ sexed semen and 3) GenChoice™ 4M sexed semen. The screenshots shown below walk you through the three sections in the heifer report. In all sections, you are able to edit the cells shaded light gray. The white cells are calculated values. The values shown in red indicate a financial expense or loss.
In the first section (pictured below), you will enter your # of units, price/unit, conception rate, heifer ratio and values per calf for heifers and bulls in the light gray boxes. The additional light gray cells contain values based on industry research, but these values can be altered if you have data specific to your dairy.
In the second section of the heifer report (Figure 2), GenChoice™ sexed semen is being compared to conventional semen based on your farm-specific inputs. In this section, you would again enter your farm-specific data - price/unit, conception and heifer ratio for 501 stud code semen – in the light gray cells in the upper left.
In this example, the bottom box shows GenChoice™ sexed semen is a profitable choice for this dairy when used on the first service to heifers ($8.02/unit profit) or first two services ($1.99/unit profit) compared to conventional semen. If GenChoice™ sexed semen was used on all services, it would lead to an expected loss of $4.44 per unit compared to conventional semen.
The third section of the Prospective℠ program compares GenChoice™ 4M sexed semen use to conventional semen based on farm-specific inputs. Again, you would enter your price/unit, conception rate and heifer ratio for 601 stud code semen in the light gray cells in the upper left.
In this example, the price per unit and expected conception rates have increased in comparison to the values used in Figure 2. Furthermore, in this example GenChoice™ 4M sexed semen is profitable, compared to conventional semen, when used on any number of services. Interestingly, the profit gained per unit of GenChoice™ 4M sexed semen is also greater than profit gained per unit of the traditional GenChoice™ sexed semen when compared on any number of services. If your on-farm conception rates for GenChoice™ 4M sexed semen are significantly greater, then you could expect a greater return on investment even with a higher price per unit.
Conception rates impact the return on investment from different sexed semen products. The increase in sexed semen conception rates in recent years has mostly been attributed to technology improvements.1,2 Among the improvements is sexed semen processed with SexedULTRA™, which GENEX and other A.I. organizations have been marketing for several years. However, sexed semen conception rates still trail conventional semen. Furthermore, there’s a significance variance in fertility levels among individual sires. (learn more about PregCheck+™ fertility rankings for GenChoice™ and GenChoice™ 4M sexed semen). It is not uncommon for conception rates to vary between individual sires by 10 points or more.
Ultimately, conception rates from sexed semen will continue to improve and its use in the dairy industry will continue to increase. By using the Prospective℠ program to compare sexed semen products you will be able to better utilize the products now and in the future.
Connect with us to learn how our world-class cattle genetics, progressive reproductive solutions, and value-added services can advance your operation. Click here to contact us today!