Monday, March 6, 2017
Wednesday, December 28, 2016
Sexed Semen: History and Potential By John Maday, Editor, Bovine Veterinarian December 23, 2016 | reprinted from Drovers Online Ag Journal
George Seidel, PhD, is a University Distinguished Professor at Colorado State University and a pioneer in the creation and use of sexed semen in cattle breeding.
Photo by John Maday
While the technology behind sex-sorted semen is relatively new, the tool has become commonplace, particularly in dairy breeding. And as the process for sorting, processing and using sexed semen becomes more efficient, leaving a calf’s sex up to chance could become obsolete.
“Sex is the most important genetic trait,” says Colorado State University reproductive physiologist George Seidel, who recently presented a webinar on the topic, hosted by the Dairy Cattle Reproductive Council (DCRC).
Seidel, who helped pioneer the sorting process and application for sexed semen in cattle, says some of the original research took place in the 1980s at the Lawrence Livermore National Laboratory in California. Scientists there became concerned about possible effects of radiation on workers’ offspring, and their studies of sperm led to discoveries regarding differences between sperm cells carrying X or Y chromosomes. In the late 1980s, USDA researchers found they could segregate X and Y sperm from rabbits, and in the early 1990s researchers in the United Kingdom began experimenting with producing male calves through in-vitro fertilization. In the late 1990s, Seidel and his team at CSU developed a process for creating sex-sorted cattle semen for freezing and use in artificial insemination (AI). Through the CSU Research Foundation, they formed a company, XY Inc., which was later sold to Sexing Technologies, based in Texas.
In 2006, Seidel says, about 1.5% of Holstein heifers and fewer than 1% of Holstein cows in the United States were bred using sexed semen. By 2008, sexed semen accounted for about 14.5% of breedings in Holstein heifers and around 2.5% in cows.
The process
Sorting semen is complicated by the fact that X and Y semen are virtually identical in most respects. Their size, shape, weight, electrical charge and speed are essentially the same, which is nature’s way of providing a 50/50 chance for male or female offspring. Scientists found however, there is slightly more DNA in an X sperm than a Y sperm – about 4% more in cattle. Using a DNA-binding dye, laser light and precise computer analysis, they found they could identify sperm cells based on differences in their fluorescence.The computer-controlled sorting machinery, which costs about $500,000 for a basic unit, separates semen into microscopic droplets, each ideally containing one sperm cell, and tags X sperm with a positive charge and Y sperm with a negative charge. Sperm that are non-viable or are not clearly identified are discarded in the sorting process. The system can evaluate about 25,000 droplets per second, as they move through the machine at 50 miles per hour. In a given sample, the system typically will sort off about 30% X sperm, 30% Y sperm and 40% unidentified or non-viable sperm.
Purity of the sorted samples can reach 95%, and the industry standard is 90%, but sorting takes considerable time, and the process damages more sperm cells than conventional collection and freezing, adding to the cost of each dose. A conventional dose of frozen semen contains around 20 million sperm cells. Sexed-semen doses typically contain closer to 2 million sperm cells, which provide a reasonable balance between cost and fertility. Pregnancy rates with sexed semen typically are lower than with conventional AI, although well-managed estrus synchronization, with AI timed six to 12 hours later than with conventional semen can help optimize fertility. Higher sperm counts per dose can improve fertility with sexed semen, but not enough to justify the much higher cost of production, Seidel says.
Sexed semen generally costs about $15 more per dose than conventional semen. Lower fertility and less than 100% accuracy also contribute to the overall cost per breeding with sexed semen, Seidel says
Theoretically, as the technology improves, fertility rates with sexed semen in cattle could equal or exceed those with conventional AI, as it does today in sheep. The process already does a good job of sorting off dead or non-viable sperm cells, and could eventually provide more cells per dose at cost-effective prices. Accuracy also could be improved. Current technology can produce accuracy around 95%, but the cost is higher than that for the industry standard of 90%. Those costs could drop in the future.
Currently, dairy producers often use sexed semen to select for heifer calves from their most productive females, sometimes using conventional semen from beef sires to add value to their remaining calves as beef animals. They could eventually use sexed semen to produce female calves for replacements in the milking herd and male calves for beef production. Beef producers could use a similar process, breeding for maternal heifer replacements from their best females while using male sexed semen from terminal-cross bulls to produce feeder steers from the rest of the herd.
Potentially the technology could make the use of un-sexed semen obsolete, Seidel says, adding that depending on the production system, “one sex always is more valuable than the other.
Options for Managing Winter Manure Nutrients on Cattle Operations By Jim Isleib Michigan State University Extension December 25, 2016 |
An over-wintering, cow-calf beef herd produces manure—quite a lot of
it. In one day, the average 1,250-pound beef cow produces 75 pounds of
manure and urine. This manure has approximately 0.31 pound of nitrogen
(not all of this is retained), 0.19 pound of phosphate and 0.26 pound of
potassium. The feeding method beef farmers use to deal with this
nutrient resource can have a positive impact on their forage and other
crop production system. Care should be taken to not overfeed in an area.
Too great of an accumulation of wasted hay and manure can have a
negative impact on forage yield next year.
There are four basic approaches to feeding the cow-calf herd over the winter:
Bart Lardner from the Canadian Western Beef Development Center conducted research on this issue in 2003-2005. His paper, “Winter Feeding Beef Cows – Managing Manure Nutrients,” states there was a definite difference in capture and utilization of manure nutrients between beef winter feeding systems. His conclusions include:
“Significant benefits can result from winter feeding beef cows on preselected sites due to increased capture and utilization of manure nutrients. Deposition of nutrients with cows versus machinery indicates more efficient cycling of nitrogen for subsequent pasture growth. In this study, economic calculations favored infield feeding. Cow cost per day was lower for field feeding than wintering cows in dry lot pens. Feed costs were similar between the systems, but field feeding had savings in machinery use and manure handling costs. Results also indicate that benefits from wintering cows on feeding sites can be managed to reduce daily costs with minimal impacts on cow performance.”
In effect, the most desirable winter feeding systems with regard to manure nutrient retention and recycling (in order of efficiency):
There are certainly some cow-calf farmers who feed their herds over winter in dry lot settings and do not scrape, haul and spread the accumulated manure in spring. This practice results in wasting manure nutrient resources and may present a situation posing risk to nearby surface and groundwater resources. Investment in machinery (e.g., manure spreader, bucket loader) to facilitate scraping, hauling and spreading dry lot manure should be considered.
There are four basic approaches to feeding the cow-calf herd over the winter:
- Dry lot feed yard. Confining and feeding cattle in a dry lot pen from October through April, or later. Cows are fed daily and nutrients accumulate in manure/straw pack over the winter.
- In-field bale feeders. Bale feeders are placed in a field with frequent relocation of the feeders to better distribute manure and waste feed nutrients and avoid sod damage.
- Bale processing. Unrolling or grinding and spreading one large round bale at a time in a windrow on the ground, or packed snow, out in a field. The feeding site is moved each time to allow waste feed and manure to be evenly distributed across an area.
- Bale grazing. Bales are set in place in a field in
the fall. They can be pre-arranged by forage quality. Cattle are allowed
gradual access to the bales on a planned schedule by moving temporary
electric fencing.
Winter field feeding site using bale unrolling.
What becomes of the nutrients from cattle manure and wasted feed
under each of these systems? According to University of Wisconsin
Extension’s publication, “Guidelines for Applying Manure to Cropland and Pasture in Wisconsin,”
as much as 50 percent of the total nitrogen and phosphorus and 40
percent of the potassium may be lost from manure on an open lot through
volatilization, runoff or leaching. Up to 40 percent of the nitrogen and
from 5 to 15 percent of the phosphorus and potassium may be lost during
daily hauling and spreading. Much less of the nutrients are lost when
cattle are winter fed in-field.Bart Lardner from the Canadian Western Beef Development Center conducted research on this issue in 2003-2005. His paper, “Winter Feeding Beef Cows – Managing Manure Nutrients,” states there was a definite difference in capture and utilization of manure nutrients between beef winter feeding systems. His conclusions include:
“Significant benefits can result from winter feeding beef cows on preselected sites due to increased capture and utilization of manure nutrients. Deposition of nutrients with cows versus machinery indicates more efficient cycling of nitrogen for subsequent pasture growth. In this study, economic calculations favored infield feeding. Cow cost per day was lower for field feeding than wintering cows in dry lot pens. Feed costs were similar between the systems, but field feeding had savings in machinery use and manure handling costs. Results also indicate that benefits from wintering cows on feeding sites can be managed to reduce daily costs with minimal impacts on cow performance.”
In effect, the most desirable winter feeding systems with regard to manure nutrient retention and recycling (in order of efficiency):
- Bale grazing
- Bale processing
- Dry lot feeding
There are certainly some cow-calf farmers who feed their herds over winter in dry lot settings and do not scrape, haul and spread the accumulated manure in spring. This practice results in wasting manure nutrient resources and may present a situation posing risk to nearby surface and groundwater resources. Investment in machinery (e.g., manure spreader, bucket loader) to facilitate scraping, hauling and spreading dry lot manure should be considered.
Friday, December 9, 2016
Hay: Stop the Waste By Taylor Grussing, South Dakota State University Extension November 22, 2016 | 12:30 pm EST
With winter setting in, pastures
have headed into dormancy and corn stalk grazing is well underway. Soon
it will be time to start delivering feed to the cow herd, most likely
starting with hay supplied in the form of large round or square bales.
Depending on which way these hay bales are delivered, the amount of
waste will vary. According to USDA National Agricultural Statistics
Service, over the last decade hay production has decreased 11%, while
hay prices have concurrently increased 77%. Therefore, more efficient
use of stored forages to decrease waste during delivery should be a
priority area that can be addressed rather simply by analyzing the type
of bale feeder being used.
(a) Open bale feeder.
(b) Tapered bale feeder with sheeting on lower section.
(c) Cone bale feeder with sheeting on lower and upper sections.
They found that as a percent of fescue hay bales, open feeders had the greatest waste (19.2%), with tapered feeders intermediate (13.6%) and cone feeders having the least waste (8.9%). These results agreed with previous research by other authors where cone bale feeders reduce waste with dry grass bales. However, alfalfa haylage waste was not effected by feeder design.
Overall, cone bale feeders resulted in 35% less waste than tapered bale feeders. Tapered bale feeders with lower section sheeting resulted in 29% less waste compared to open bale feeders with no lower section sheeting.
Regardless, feeding in any type of bale feeder is better than feeding directly on the ground which greatly increases waste and thus pounds of feed required per day to meet nutritional requirements. Expenses related to wasted hay and extra pounds of hay needed to meet requirements can add up quickly. If as little as 1 lb. of waste/cow/day accumulates over a 4-month winter feeding period, this adds an extra $5 to her winter feed bill ($80/ton). And this expense will continue to increase with tapered and open bale feeders as more waste is expected, respectively. In an effort to prevent increasing the winter feed bill, a new bale feeder design or feeding plan may need to be developed and put into action in order to manage hay waste this winter.
Bale Feeder Design & Hay Waste
Moore and Sexten (2015) analyzed the effect of bale feeder design on hay waste at the University of Missouri Agriculture Experiment Station. The four bale feeders evaluated were: (a) open bale feeder, (b) tapered bale feeder with sheeting on lower section and (c) cone bale feeder with sheeting on lower and upper sections. Two different types of hay: alfalfa haylage bales and fescue hay bales were also utilized to evaluate interaction of bale feeders and forage. All bales were placed into bale feeders horizontally and cows utilized in the study were accustomed to bale feeders and forage types prior to study initiation.
(a) Open bale feeder.
(b) Tapered bale feeder with sheeting on lower section.
(c) Cone bale feeder with sheeting on lower and upper sections.
They found that as a percent of fescue hay bales, open feeders had the greatest waste (19.2%), with tapered feeders intermediate (13.6%) and cone feeders having the least waste (8.9%). These results agreed with previous research by other authors where cone bale feeders reduce waste with dry grass bales. However, alfalfa haylage waste was not effected by feeder design.
Overall, cone bale feeders resulted in 35% less waste than tapered bale feeders. Tapered bale feeders with lower section sheeting resulted in 29% less waste compared to open bale feeders with no lower section sheeting.
Stocking Density & Bale Size
In addition, stocking density and size of bales can also play a key role in forage waste. Greater stocking density will increase competition around bale feeders and reduce the time cows spend entering and exiting the feeder, potentially decreasing waste. Also, bale size may have been one reason there was less waste with alfalfa haylage than fescue hay. As the alfalfa haylage bales were smaller, providing cows more feeding space in bale feeders reduced the entrance/exit frequency and waste opportunities.The Bottom Line
Cow/calf producers can prepare for winter feeding by taking a look at the type of bale feeders on hand. Do bale feeders have sheeting on the lower section? If not, can some kind of sheeting (metal or plastic) be added to help decrease waste this winter? Are enough bale feeders available for size of cowherd or do more need to be purchased?Regardless, feeding in any type of bale feeder is better than feeding directly on the ground which greatly increases waste and thus pounds of feed required per day to meet nutritional requirements. Expenses related to wasted hay and extra pounds of hay needed to meet requirements can add up quickly. If as little as 1 lb. of waste/cow/day accumulates over a 4-month winter feeding period, this adds an extra $5 to her winter feed bill ($80/ton). And this expense will continue to increase with tapered and open bale feeders as more waste is expected, respectively. In an effort to prevent increasing the winter feed bill, a new bale feeder design or feeding plan may need to be developed and put into action in order to manage hay waste this winter.
VFD Lessons and Next Steps By John Maday, Editor, Bovine Veterinarian December 08, 2016 | 10:22 am EST reprint from Drovers
While we stare at the January 1
implementation of the FDA’s new veterinary feed directive (VFD) rules,
it is important to note that the VFD itself is not new. The FDA has
required VFDs for certain medicated feeds for years. Most of those have
applied to other livestock species, but for cattle, Elanco’s Pulmotil
(tilmicosin) product for BRD control has required a VFD since it was
introduced in 1996.
During the recent Academy of Veterinary Consultants (AVC) conference, Elanco Animal Health technical services specialist Guy Hufstedler, PhD, outlined some of his company’s experiences and lessons learned through marketing a VFD drug.
First, he says, teamwork is critical for animal-health management and for ensuring compliance with the VFD rules. Producers need to work closely with their veterinarians, nutritionists and feed suppliers, and also look to the companies that market VFD products for information and advice. All parties involved need to make their best efforts to comply with the law, and not look for loopholes or “work-arounds.” For more on action steps for VFD compliance, read VFD plan from BovineVetOnline.com.
FDA will conduct VFD-related inspections at feed distributors, veterinary clinics and cattle operations. At that point, each party must demonstrate they have the required VFD forms on file and the forms contain all the required information. When a producer can quickly access and provide the requested records, it inspires confidence on the part of the FDA inspector and probably results in a positive outcome. In contrast, Hufstedler says if a producer cannot find the requested VFD records, the inspection is off to a bad start.
As for the VFD forms, veterinarians and producers need to work together to ensure the proper information is included, and that all the information about the drug, dosage, intended use, duration of use and withdrawal times conform with the product label. Note that VFD forms specifically state that “Use of feed containing this Veterinary Feed Directive drug in a manner other than directed on the label (extra-label use) is not permitted.”
Animal-health companies provide VFD forms specifically for their products, which can help simplify the process. The form for tilmicosin, for example, states the indication for use as “Control of BRD,” which is the only indication on the product label for cattle. For duration of use, the form specifies 14 days, which is the approved duration listed on the label.
Another of Elanco’s popular products, Tylan (tylosin) Premix, will require a VFD beginning on January 1. Tylosin is approved for continuous use for reducing the incidence and severity of liver abscesses in cattle. Hufstedler notes the “continuous use” application remains valid. Cattle feeders have expressed some concern that as cattle feed intakes change over the feeding period, intake of tylosin could vary from the grams per ton entered on the VFD form. Hufstedler says the FDA understands the variation inherent to biological systems, and he suggests entering a dosage range of eight to 10 grams per ton (on a 90% dry-matter basis), as specified on the product label.
During a panel discussion at the AVC conference, Kansas State University veterinarian Mike Apley, DVM, PhD, outlined some issues FDA is likely to evaluate in the coming months and years. These include:
· Continuous feeding of a medically important antimicrobial with no defined duration. FDA recently issued a Federal Register notice outlining it plans to reexamine indications for VFD drugs that currently have undefined durations of use. For more on this issue, read “Antibiotic Rules: Knowledge Gap Remains” from BovineVetOnline.com.
· “Pulsing” in the use of medicated feeds.
· Action on the remaining OTC antimicrobials.
· Distribution of Type A medicated articles. Type A medicated articles are the most concentrated form of feed-grade antibiotics, which are mixed with other ingredients to create Type B or C medicated feeds
For more information on the VFD rule and related regulations, visit the FDA’s Veterinary Feed Directive website.
For more information on AVC, and access to recordings of entire presentations at AVC conferences, visit AVC-beef.org.
During the recent Academy of Veterinary Consultants (AVC) conference, Elanco Animal Health technical services specialist Guy Hufstedler, PhD, outlined some of his company’s experiences and lessons learned through marketing a VFD drug.
First, he says, teamwork is critical for animal-health management and for ensuring compliance with the VFD rules. Producers need to work closely with their veterinarians, nutritionists and feed suppliers, and also look to the companies that market VFD products for information and advice. All parties involved need to make their best efforts to comply with the law, and not look for loopholes or “work-arounds.” For more on action steps for VFD compliance, read VFD plan from BovineVetOnline.com.
FDA will conduct VFD-related inspections at feed distributors, veterinary clinics and cattle operations. At that point, each party must demonstrate they have the required VFD forms on file and the forms contain all the required information. When a producer can quickly access and provide the requested records, it inspires confidence on the part of the FDA inspector and probably results in a positive outcome. In contrast, Hufstedler says if a producer cannot find the requested VFD records, the inspection is off to a bad start.
As for the VFD forms, veterinarians and producers need to work together to ensure the proper information is included, and that all the information about the drug, dosage, intended use, duration of use and withdrawal times conform with the product label. Note that VFD forms specifically state that “Use of feed containing this Veterinary Feed Directive drug in a manner other than directed on the label (extra-label use) is not permitted.”
Animal-health companies provide VFD forms specifically for their products, which can help simplify the process. The form for tilmicosin, for example, states the indication for use as “Control of BRD,” which is the only indication on the product label for cattle. For duration of use, the form specifies 14 days, which is the approved duration listed on the label.
Another of Elanco’s popular products, Tylan (tylosin) Premix, will require a VFD beginning on January 1. Tylosin is approved for continuous use for reducing the incidence and severity of liver abscesses in cattle. Hufstedler notes the “continuous use” application remains valid. Cattle feeders have expressed some concern that as cattle feed intakes change over the feeding period, intake of tylosin could vary from the grams per ton entered on the VFD form. Hufstedler says the FDA understands the variation inherent to biological systems, and he suggests entering a dosage range of eight to 10 grams per ton (on a 90% dry-matter basis), as specified on the product label.
Next steps?
The upcoming changes to antibiotic regulations in animal agriculture do not represent the end of the process. Veterinarians believe the FDA will continue to assess management practices, monitor antibiotic-resistance trends and make additional changes toward a goal of improving stewardship.During a panel discussion at the AVC conference, Kansas State University veterinarian Mike Apley, DVM, PhD, outlined some issues FDA is likely to evaluate in the coming months and years. These include:
· Continuous feeding of a medically important antimicrobial with no defined duration. FDA recently issued a Federal Register notice outlining it plans to reexamine indications for VFD drugs that currently have undefined durations of use. For more on this issue, read “Antibiotic Rules: Knowledge Gap Remains” from BovineVetOnline.com.
· “Pulsing” in the use of medicated feeds.
· Action on the remaining OTC antimicrobials.
· Distribution of Type A medicated articles. Type A medicated articles are the most concentrated form of feed-grade antibiotics, which are mixed with other ingredients to create Type B or C medicated feeds
For more information on the VFD rule and related regulations, visit the FDA’s Veterinary Feed Directive website.
For more information on AVC, and access to recordings of entire presentations at AVC conferences, visit AVC-beef.org.
Thursday, May 5, 2016
Are You Ready for Breeding Season? from Drovers
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Taking Your Records Mobile
Producers, here is a new tool you may want to consider for your record keeping of your breeding schedule and calf records. Check it out.
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