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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Biological and Economic Effects of Grazing Spring-Calving Cow-Calf Pairs on Improved Irrigated Pastures Using Creep Supplementation

Summers, Adam F 01 May 2009 (has links)
Recent trends to develop farmland into improved irrigated pastures raise questions regarding the profitability of creep supplementing terminal-sired calves on these production systems. This study was initiated to answer these questions. Two previously established adjacent sprinkler-irrigated plots were separated into 2 paddocks. One plot (3.4 ha) consisted of a monoculture of Seine tall fescue while the other plot (3.9 ha) consisted of a mixture of Seine tall fescue, AC Grazeland Alfalfa, and Norcen birdsfoot trefoil. The mixture of the second plot consisted of 50% tall fescue, 37.5% alfalfa, and 12.5% birdsfoot trefoil. Plots were designated as monoculture no-creep supplement (MONOC) (1.7 ha), monoculture with creep supplement (MONOS) (1.7 ha), mixed forage no-creep supplement (MIXC) (1.95 ha), and mixed forage with creep supplement (MIXS) (1.95 ha). Twenty-four spring calving cow-calf pairs were stratified into 4 groups based on calf body weight, sex, breed, dam body weight, dam BCS, and breed. Management-intensive grazing practices were implemented with cattle receiving a new allotment of forage at 0800 daily. Cattle grazed in a west-to-east direction across the pasture completing a grazing circuit every 24 to 30 d. Pasture forage production was estimated using a 0.163 m2 clip-plot. Forage production each period was highest for cattle grazing MIXS (4492 kg DM/ha) followed by MIXC (4116 kg DM/ha) (P=.58). Production from the MIX plot differed from MONO plot (P<.0001). Similar to MIX pasture production MONOC (3154 kg/ha) and MONS (3058 kg/ha) did not vary (P=.4324). Carrying capacity differed among all treatments. The highest carrying capacity was observed in the MIXS group with 3.37 pair/ha. The next highest carrying capacity was in the MIXC group at 3.05 pair/ha, which differed from MIXS (P=.0404). There was a difference between MIXC and MONOS (2.38 pair/ha) (P=.0051). The lowest carrying capacity was observed in the MONOC group (2.07 pair/ha), differing from MONOS (P=.0450). Calf end weight was highest for the MIXS group (343 kg) and differed from MONOC group (298 kg) (P=.0272); no other groups differed. Profitability did not follow pasture productivity completely. Due to high supplemental feed costs MIXC was the most profitable management strategy ($72.03 cow/yr) and was $137.50 cow/yr more profitable than the least profitable strategy, MONOS. Results from this study show that grass-legume mixtures are much more productive than grass monocultures under irrigation and management-intensive grazing of cow-calf pairs. In addition, on these forage resources the practice of supplying creep supplementation to high-growth, terminal calves is not economically profitable.

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