A Method for Estimating Weaning Weights of Range Calves at a Constant Age

Koger, M.; Knox, J. H.

doi:10.2527/jas1945.43285x

Cited by 10 publications

(5 citation statements)

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“…Average daily BW gains were determined for each cow from prepartum BW to BW nadir, BW nadir to the end of breeding, BW nadir to the end of supplementation, end of supplementation to the end of breeding, and end of breeding to weaning. Calf BW was recorded monthly through the end of breeding and at weaning ( Figure 2) for calculation of adjusted 205-d weaning weight (Koger and Knox, 1945). Calf 205-d weaning weights were not adjusted by sex of calf or age of dam.…”

Section: Measurementsmentioning

confidence: 99%

Effects of supplements that contain increasing amounts of metabolizable protein with or without Ca-propionate salt on postpartum interval and nutrient partitioning in young beef cows1

Waterman

Sawyer

Mathis

et al. 2006

Journal of Animal Science

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Cattle grazing winter range forages exhibit interannual variation in response to supplementation. This variation may be mediated by circulating concentrations and subsequent metabolism of glucose, which are influenced by forage quality and availability. A study conducted at the Corona Range and Livestock Research Center during 2 dry years evaluated responses of young postpartum beef cows (n = 51, initial BW = 408 +/- 3 kg, and BCS = 5.1 +/- 0.04 in year 1; n = 36, initial BW = 393 +/- 4 kg, and BCS = 4.5 +/- 0.05 in year 2) to supplements that met or exceeded metabolizable protein (MP) requirements. Supplements were fed at 908 g/d per cow and provided 327 g of CP, 118 g of ruminally undegradable protein (RUP), and 261 g of MP from RUP (RMP), calculated to meet the MP requirement; 327 g of CP, 175 g of RUP, and 292 g of MP from RUP (RMP+), which supplied 31 g of excess MP; or 327 g of CP, 180 g of RUP, 297 g of MP from RUP, and 100 g of propionate salt (NutroCal, Kemin Industries, Inc., Des Moines, IA; (RMP+)P), which supplied 36 g of excess MP. Body weights were recorded once every 2 wk, and blood samples were collected 1x/wk in year 1 and 2x/wk in year 2 for 100 d postpartum. Postpartum anestrous was evaluated by progesterone from weekly blood samples, and pregnancy was confirmed by rectal palpation at weaning. As MP from RUP with or without propionate increased, a decrease (P = 0.03) was observed in postpartum interval; however, differences in pregnancy percentage (P = 0.54) were not influenced by treatments. We hypothesized that additional AA from RUP along with propionate would increase supply of glucogenic precursors and, therefore, glucogenic potential of the diet. Therefore, a postpartum glucose tolerance test was conducted near the nadir of cow BW to evaluate the rate of glucose clearance. Glucose tolerance tests showed that (RMP+)- or (RMP+)P-supplemented cows had greater (P = 0.03) rates of glucose clearance, which might have influenced the observed abbreviation of the postpartum interval. A glucose tolerance test conducted at the end of supplemental treatments revealed no differences in glucose clearance (P = 0.47) among previously supplemented cows. These data suggest that not only vegetative quality, duration of lactation, and season of grazing, but also type of supplementation may play a pivotal role in the young postpartum beef cow's ability to respond and incorporate nutrients into insulin-sensitive tissues.

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Section: Measurementsmentioning

confidence: 99%

Effects of supplements that contain increasing amounts of metabolizable protein with or without Ca-propionate salt on postpartum interval and nutrient partitioning in young beef cows1

Waterman

Sawyer

Mathis

et al. 2006

Journal of Animal Science

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“…Lush (1936) and Black (1936) called for objective measures of merit in beef cattle. Heritability estimates for growth by Knapp and Nordskog (1946) and Koger and Knox (1945) on weight adjustment stimulated research interests. Three regional beef breeding projects were initiated and beef research began in ernest (Willham, 1977).…”

Section: Scientificmentioning

confidence: 99%

Genetic Improvement of Beef Cattle in the United States: Cattle, People and Their Interaction

1982

Journal of Animal Science

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The purpose of this essay is to develop a historic perspective of the beef cattle population and the legion of people directing its genetic change so that future leadership can increase the rate of breeding technology assimilation. Use of cattle for beef to feed millions is relatively recent. The beef industry of the United States has a rich, romantic heritage that combined Spanish exploitation with British tradition. Spanish cattle became adapted as the Texas longhorn and the European cattle became indigenous. Breeds developed in Britain replaced both. The Zebu was introduced to produce cattle adapted to the Gulf Coast. Selection for early maturity in the British breeds promoted by livestock shows was ended by the dwarf gene. The Charolais breed demonstrated growth potential. Then in 1967, Continental European breeds were imported, given an array of biological types from which to select. Beef cattle breeding research expanded after the second world war through the three regional projects. Performance Registry International was the focal point for performance. The Beef Improvement Federation produced guidelines for recording beef performance including those for national sire evaluation. U.S. Meat Animal Research Center evaluated the several newly introduced breeds. To date, breeding researchers have developed breeding technology for the use by breeder. The major breed association are keeping and utilizing performance records. The genetic structure of the beef breeds is being altered by the use of AI such that genetic change can be made rapidly by the use of superior sires evaluated on their progeny in many herds.

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“…(1955) and Chambers _et (1956). Minyard and Dinkel (1960) The other most common methods of correcting for age of calf are by covariance analysis (Koger and Knox, 1945a) or by the regression of weight on age within year, sex, and age of dam subclass groups (Koger and Knox, 1945b;Koger and Knox, 1947). …”

Section: Personnel Associated With Federal Experiments Stations Weanmentioning

confidence: 99%

Beef calf weights at 100 days and 205 days as indicators of dams' producing ability

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A Method for Estimating Weaning Weights of Range Calves at a Constant Age

Cited by 10 publications

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Effects of supplements that contain increasing amounts of metabolizable protein with or without Ca-propionate salt on postpartum interval and nutrient partitioning in young beef cows1

Effects of supplements that contain increasing amounts of metabolizable protein with or without Ca-propionate salt on postpartum interval and nutrient partitioning in young beef cows1

Genetic Improvement of Beef Cattle in the United States: Cattle, People and Their Interaction

Beef calf weights at 100 days and 205 days as indicators of dams' producing ability

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