Effects of calf removal studied

Effects of calf removal studied

A new University of Florida study is shedding light on how calf removal can affect the cow during the breeding season.

BREEDING season can be very challenging for many beef producers, especially if artificial insemination is the main breeding method for the operation.

A new University of Florida study is shedding light on how calf removal can affect the cow during the breeding season.

Luteinizing hormone (LH) is a key part of the reproduction process. When LH levels rise, it triggers ovulation. According to the study, however, LH is depleted in the anterior pituitary gland as a result of a massive release of hormones during calving.

A past study found that nursing calves extend the amount of time it takes for a cow to return to her normal cycle after calving.

Another previous study found that decreasing the frequency of suckling or temporarily removing the suckling improved LH secretion, shortened the calving-to-first-ovulation interval and increased the number of cows that became pregnant early in the breeding season. Additionally, it was found that resuming nursing caused LH to return to baseline levels.

Two different experiments were conducted to evaluate the duration of calf removal on estradiol concentrations, growth of the pre-ovulatory follicle and pregnancy rate in synchronized artificial insemination. The Florida researchers also evaluated the effects of calf removal on calf performance.

Three different groups of beef cows were studied: (1) a control group, (2) a group that removed calves for 48 hours and (3) a group that removed calves for 72 hours. Calf groups were categorized as young (25-59 days old), medium (60-79 days old) and old (more than 80 days).

Calves received unlimited access to water and hay during the calf removal time, and at one location, calves were given creep feed 20 days before removal and during removal.

The results for pregnancy rates were mixed. Cows nursing older and medium-aged calves had a greater pregnancy rate percentage than cows with younger calves, but overall, calf removal did not affect pregnancy rates.

The researchers found that follicular growth rate was greater in both the 48-hour and 72-hour calf removal groups than in the control group; however, calf removal did not increase the diameter of the follicle. They also observed that removing the calves increased estradiol concentrations after 24 hours.

As for the effect on the calves, bodyweight was adversely affected for both the 48-hour and 72-hour groups. The results did vary, however, depending on the removal duration and age of the calf.

For example, at one location, old calves and young calves in the removal group lost a greater amount of weight than the medium-aged calves and the control group. During the study, the greatest weight loss was observed in young calves from the removal groups.

In the group that received creep feed, the researchers found that it may have inhibited the negative impacts of calf removal on bodyweight and also may have enhanced bodyweight gain after cows and calves were reintroduced. The report notes that calves did not experience any differences in average daily gain or bodyweight over the entire experiment.

The researchers concluded that removing calves produced mixed and inconsistent results. Removing the calves showed improvements in some areas but ultimately did not increase pregnancy rates or positively benefit the calves — two of the main concerns for beef cattle producers.


Defining sustainable beef

Defining what constitutes sustainable beef production is not an easy task. Given the vast differences in climate, available grains and forages, water resources, management practices and labor between one beef-producing region and another around the globe, a definition must be constructed carefully in order to fully communicate the principles of sustainability and sustainable practices.

Working as a committee within the Global Roundtable for Sustainable Beef (GRSB), a group of representatives from Argentina, Australia, Brazil, Canada, the European Union and the U.S. met in April in Chicago, Ill., to begin working on GRSB's definition framework for sustainable beef. Due to the complexity of the issue, however, it said more experts are needed.

According to Bryan Weech, a member of the GRSB executive committee and director for livestock at the World Wildlife Fund, "it is imperative that a full range of subject matter experts in the many areas of beef sustainability be involved in this process. We need to assure that all areas and points of view are represented so that the definition developed is as accurate and complete as possible."

The GRSB Beef Sustainability Definition Committee is chaired by Ruaraidh "Rory" Petre, who is also executive director of the roundtable.

According to Petre, GRSB "was formed in 2012 as an international nonprofit organization, and one of its first efforts has been the formation of a highly qualified committee of members and others who are experts in beef sustainability. The definition committee has broad geographic diversity and is intent on identifying the key principles of beef sustainability as well as a clear path forward for the creation of criteria to fit under those principles."

When developing the principles and criteria, the committee has agreed to adhere to a set of credibility principles as follows:

* Sustainable — clearly and objectively defined;

* Relevant, rigorous, engaged — with a balanced, representative group of stakeholders;

* Impartial, transparent, accessible — inclusive, and

* Truthful and efficient — engaged with other initiatives in a similar space.

Petre noted that "the definition committee is working on principles and criteria and next steps towards regional development of indicators, but there is no plan to develop a seal, certification or comparable standard."

The core principles identified by the committee during its April meeting include people, community, animal well-being, food, natural resources, efficiency and innovation. Criteria under the principles include issues such as labor and workers' rights; the well-being of local communities; the well-being of animals in various management systems; food safety, nutrition and food security; air, soil and water quality, and energy conservation and waste reduction.


Beef cattle course

The Texas A&M Beef Cattle Short Course is scheduled for Aug. 5-7 at Texas A&M University.

A weather outlook and a cattle market outlook are two of the featured topics to be discussed during the general session on Aug. 5.

"A lot of producers are wanting to know how long this current market cycle will last and how to go about herd expansion strategies in the future," said Jason Cleere, Texas A&M AgriLife Extension Service beef cattle specialist in College Station, Texas, and conference coordinator. "The long-term outlook is one of the many topics that will be featured in the 22 different Cattleman's College sessions at the short course."

The short course has become one of the largest and most comprehensive beef cattle educational programs in the U.S., Cleere noted.

The Cattleman's College portion provides participants with an opportunity to choose workshops based on their level of production experience and the needs of their ranch, Cleere said.

"These concurrent workshops will feature information on introductory cattle production, retiring to ranching, management practices in the areas of forage, nutrition and reproduction, recordkeeping, genetics, purebred cattle, landowner issues and much more," he said.

In addition to classroom instruction, participants can attend one of several demonstrations on Aug. 7.

"There will be demonstrations on fence building, chute-side calf working, cattle behavior, penning and Brush Busters," Cleere said. "These provide an opportunity for ranchers to see beef cattle production practices put to use."

Registration information and a tentative schedule can be found at http://beef.tamu.edu.

Volume:85 Issue:24

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