Differences in serum immunoglobulin g1 and total protein concentrations in neonatal calves on days 1, 5, and 10

Immunoglobulin G1 (IgG1) serum concentrations are used to evaluate passive transfer of immunity in neonatal calves. Total serum proteins also can be measured to evaluate calf health. If IgG1 and total serum protein concentrations change with age, it becomes imperative to compare samples only from a narrow time period. Otherwise, differences might be due to age and not immune status. To help define this time period, blood was drawn from 10 beef calves when they were 1, 5, and 10 days of age. Serum samples were analyzed for IgG1 and total protein concentrations. Total protein concentrations decreased from days 1 to 5 (P\u3c.05) or days 1 to 10 (P\u3c.05), but not from days 5 to 10 (P=.46). IgG1 concentrations declined from days 1 to 10 (P\u3c.05), but values from days 1 to 5 were similar (P=.17). Thus, it is important to collect serum on day 1 to guarantee correct results when evaluating IgG1 and total proteins collectively. However, if IgG1 alone is evaluated, serum can be collected between days 1 and 5

Using Arsoy™ as a protein supplement in growing cattle diets

Arsoy™ Soybean Feed is a by-product from the manufacture of soy protein isolate. It contains nearly 30% crude protein, but there is little documentation about its feeding value. Therefore, we fed basal growing diets of corn silage and stover to 196 crossbred heifers and supplemented those diets with soybean meal, Arsoy, or a combination of soybean meal and high moisture corn to determine the feeding value of Arsoy. Our results suggest that Arsoy can be substituted for soybean meal in growing cattle diets, without any negative impact on animal performance, dry matter intake, or feed efficiency

Performance of calves born to beef cows seropositive but subclinical for bovine leukosis virus

Calves from a commercial beef herd were evaluated for weight gain differences based upon the bovine leukosis virus (BLV) serological status of their dams. One hundred forty-two multiparous cows from a commercial beef herd were tested for BLV by agar gel immunodiffusion. Eighty-nine cows (62.6%) were found to be seropositive for BLV. Weights were collected from all calves at weaning, from heifers on the date when selection of replacement heifers was made, and from steers on the day of harvest after being fed to finish weight in a feedlot. Offspring from seronegative cows tended to have heavier weaning weights (+17 lb) and heifer selection weights (+31 lb) than those from seropositive cows

Relationship of milk expected progeny differences (EPD\u27s)to milk production and calf weaning weight

Spring-calving Angus (n=37) and Simmental (n=28) cows were used to evaluate the relationship between milk expected progeny difference (EPD), milk production, total milk energy, and weaning weight. There were positive correlations between milk EPD\u27s and milk produced during lactation, total milk energy per lactation, and calf weaning weight. On average, a 1 lb increase in milk EPD predicted a 1.8 lb increase in calf weaning weight and an increase of 56.6 (Angus) and 70.2 (Simmental) lb in total milk per lactation. Our results suggest that producers can use milk EPD\u27s as selection tools to influence the milk production of their cows and subsequent weaning weights of their calves

Performance of calves born to beef cows seropositive but subclinical for bovine leukosis virus

Calves from a commercial beef herd were evaluated for weight gain differences based upon the bovine leukosis virus (BLV) serological status of their dams. One hundred forty-two multiparous cows from a commercial beef herd were tested for BLV by agar gel immunodiffusion. Eighty-nine cows (62.6%) were found to be seropositive for BLV. Weights were collected from all calves at weaning, from heifers on the date when selection of replacement heifers was made, and from steers on the day of harvest after being fed to finish weight in a feedlot. Offspring from seronegative cows tended to have heavier weaning weights (+17 lb) and heifer selection weights (+31 lb) than those from seropositive cows

Comparison of feed efficiency rankings of heifers fed low and high energy dense diets

Concepts related to energy efficiency in cattle have been the basis for many research projects. Even though differences in individuals have long been recognized, little effort has been focused on the causes of the observed variations. The concept of residual feed intake was first introduced in 1963, and is calculated as the difference between actual feed intake by an animal and its expected feed intake based on body weight and growth rate. Residual feed intakes are phenotypically independent of the production traits used to calculate expected feed intake. Consequently, residual feed intake values can be useful in comparing individuals differing in level of production during a test period. These feed efficiency calculations have been shown to be a more accurate indicator of genetic variation in efficiency because they are independent of production traits. Thus, selection for improved residual feed intake makes it feasible to reduce feed intake without compromising growth performance. Hence, this trait could have great economic value to all segments of the beef industry. Energy density of cattle diets varies substantially and the selection for the ability to efficiently utilize high roughage diets does not guarantee efficient utilization of high grain diets. The objective of this study was to determine if energy density of the diet influences the ranking of cattle within a contemporary group and to determine if residual feed intake is influenced by changes in body composition and diet digestibility

Evaluation of southwestern Kansas native grasses

Native grass samples were collected monthly for five years and analyzed for nutrient content. Crude protein and ADF content indicate that grass quality is highest in May and June, then steadily declines until October. Stocker operators may need to begin protein supplementation as early as July to sustain weight gains. Trace mineral values were erratic from year to year and month to month between and within years, indicating that trace mineral supplementation should probably be maintained throughout the grazing season

Feeding melengesterol acetate (MGA) in advance of estrus synchronization of virgin beef heifers

The objective of this experiment was to determine if a 7-day feeding of melengesterol acetate (MGA) about 2 months before the breeding season would have an effect on puberty onset, response to estrous synchronization, and fertility. “Progesterone priming” with MGA increased the number of heifers that began cycling before estrous synchronization. This did not increase the percentage of heifers that were observed in standing heat after estrous synchronization, however, regardless of whether standard MGA/PGF or Select Synch protocol was used. The conception rates and overall pregnancy rates were similar between treatments. Many factors affect the reproductive performance of replacement heifers; slight decreases in the age of puberty onset seem to have little effect

Short-term feeding of MGA to postpartum cows prior to the breeding season

A protocol to make anestrous cows more likely to cycle prior to estrous synchronization would greatly enhance reproductive efficiency. Ease of application, availability, and low cost make feeding melengestrol acetate (MGA) a good choice in such a protocol. MGA, used as a progestin “primer,” has no detrimental effects on cows that are already cycling and reduces the number of cows expressing short cycles