Effect of selection for feedlot gain, breed and age on growth hormone and growth hormone kinetics in bull calves

Mears, G. J.; Kozub, G. C.

doi:10.4141/cjas95-008

Cited by 4 publications

(1 citation statement)

References 24 publications

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“…Other authors (Mears and Kozub, 1994) also reported a lack of dietary effects on basal GH concentrations for diets differing in DM digestibility and protein content. In contrast, Cole et al (1988) found that GH concentrations in sheep were higher in low than high energy level diets.…”

Section: Discussionmentioning

confidence: 98%

Growth, blood metabolites and hormones in calves fed diets with different amounts of energy and protein during the pre- or post-weaning periods

Fernández¹

2012

Afr. J. Agric. Res.

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We investigated the effects of diets differing in energy and protein concentrations given during pre-and post-weaning on hormone and metabolite levels in association to parameters of growth. Sixteen Aberdeen Angus calves four-day-old were allocated in individual pens during 105 days in a randomized complete design. Animals consumed ad libitum various diets differing in proportion of energy and protein (A: 80% of concentrate, 20% alfalfa hay; B: 60% concentrate, 40% of alfalfa hay; C: 40% concentrate, 60% alfalfa hay, and D: 20% concentrate, 80% alfalfa hay). Also, calves consumed milk substitute up to 60-day-old day. Serum growth hormone and cortisol levels were not altered with diet changes (P > 0.05) neither during the pre-nor the post-weaning periods. Plasma insulin concentration average daily intake, glucose and thyroid hormone levels, and concentrations of ammonia nitrogen and propionic acid were greater (P < 0.01) for diets having higher than lower energy and protein levels during the post-weaning but not during the pre-weaning period. These results suggest inclusion of higher amounts of concentrate in the diet of weaned calves.

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Section: Discussionmentioning

confidence: 98%

Growth, blood metabolites and hormones in calves fed diets with different amounts of energy and protein during the pre- or post-weaning periods

Fernández¹

2012

Afr. J. Agric. Res.

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The effect of intake level on whole body kinetics and hepatic removal of somatotropin in growing beef steers☆

Lapierre

Farmer

Reynolds

et al. 2000

Domestic Animal Endocrinology

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Understanding Factors That Influence Breeders to Sell Bulls at Performance Tests

Lillywhite

Simonsen

2008

J. Agric. Appl. Econ.

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Breeders of purebred bulls have multiple avenues to market their bulls, including consignment at public auctions associated with performance tests. Purebred breeders often have the opportunity to withdraw bulls that are eligible to sell in these auctions. We examine sales data from a public auction held in conjunction with a performance bull test in Tucumcari, NM, to gain insights on breeder decisions to withdraw bulls prior to entering the sales ring. Specifically, we use a binary logit model to identify relevant characteristics that affect a breeder's decision to withdraw a sale eligible bull from the auction.Key Words: breeder decisions, livestock, performance bull testPerformance bull tests are a well-known means of facilitating market interaction between sellers of purebred cattle and buyers (e.g., cow-calf producers). Performance tests bring together bulls from varied genetic and environmental backgrounds at one testing facility to compare growth performance against bulls of the same breed. In many cases, on completion of the performance test, breeders may elect to sell their eligible bulls at after-test auctions. Eligibility may vary from test to test but generally requires the bull to be healthy and to have met minimum test performance standards.Auctions like those associated with performance bull tests are particularly effective, as traits of the auction commodity (i.e., purebred bulls) can be highly variable (Tomek and Robinson). In addition to facilitating market interaction between seller and buyer, the combination of performance test and the ensuing auction can improve market efficiency. For example, information on a specific animal collected during the test is often published in a presale catalog, providing important information to potential buyers. The disseminated information can effectively lower search costs and reduce product uncertainty for potential buyers.In order for performance tests and aftertest auctions to operate effectively, managers must be attentive to a variety of concerns; among these is the assurance that an adequate number of animals are available for sale in the auction. Consistent shortages of animals available for sale at these auctions reduce search cost savings for potential buyers. As costs savings decrease, fewer buyers will participate in the auction, as other costs (e.g., transportation costs) may begin to

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Effect of selection for feedlot gain, breed and age on growth hormone and growth hormone kinetics in bull calves

Cited by 4 publications

References 24 publications

Growth, blood metabolites and hormones in calves fed diets with different amounts of energy and protein during the pre- or post-weaning periods

Growth, blood metabolites and hormones in calves fed diets with different amounts of energy and protein during the pre- or post-weaning periods

The effect of intake level on whole body kinetics and hepatic removal of somatotropin in growing beef steers☆

Understanding Factors That Influence Breeders to Sell Bulls at Performance Tests

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