Growth parameters of Holstein-Friesland heifers reared on complete diets containing different roughages

At two months of age, 48 Holstein-Friesland heifers were randomly allocated to four treatments comprising untreated wheat straw (WS), oven-ammoniated wheat straw (AWS), lucerne hay (LH) or oat hay (OH). Least cost nutrient balanced complete diets were formulated for heifers of different age groups, i.e. 2–6, 6–10, 10–13, 13–18 months and 18 months to first calving. Dry matter (DM) intakes of individual heifers were determined twice weekly. Animals were weighed once weekly, and girth circumference and wither height were measured monthly. From 13 months of age, heifers were observed daily for oestrus and inseminated provided that a minimum live weight of 290 kg had been attained. At two months of age, heifers weighed (mean ± s.e.) 69 ± 1.1 kg and wither height and girth circumference measured 84.6 ± 0.4 and 94.1 ± 0.6 cm respectively. The average daily gain of heifers receiving diets containing LH was higher (P 0.05) between treatments, the overall mean being 129.3 ± 0.5 cm. Girth circumference of heifers fed diets containing WS, AWS and OH was smaller (P < 0.001) than that of heifers fed LH (179.2, 177.3 and 176.7 cm vs. 188.3 cm respectively). Heifers fed diets containing LH also had higher (P < 0.01) condition scores than heifers fed diets containing other roughages. The lower feeding cost of AWS diets in comparison to other diets should be utilized fully in the rearing of replacement heifers. (South African Journal of Animal Science, 2000, 30(2): 121-127

Evaluation of cottonseed oil-cake meal as a protein source in calf starter meals

The growth performance of 18 Holstein and 20 Jersey heifer calves fed calf starter meals containing either cottonseed oil-cake meal (CSOCM) or soybean oil-cake meal (SBOCM) was compared. The diets were iso-nutritious in terms of crude protein and energy, and were fed from two weeks of age until two or three months of age to Holstein or Jersey calves respectively. Jersey and Holstein calves weighed 21.4±0.5 and 35.9±1.4 kg respectively at the start of the experiment. There were no differences between calf starter meals containing CSOCM or SBOCM (p > 0.05) in respect of feed intake, growth rate or efficiency of feed conversion. Average daily gain of Jersey and Holstein heifer calves was 0.435±0.02 and 0.635±0.03 kg/day respectively. No calves died during the experiment. It was concluded that the most important criterion for inclusion of CSOCM in calf starter meals is the cost of CSOCM relative to that of SBOCM, provided that the CSOCM used has a gossypol content of less than 200 ppm. (South African Journal of Animal Science: 2000, 30(1): 67-69

The production performance of lactating Jersey cows receiving varying levels of lucerne hay and oat silage as roughage sources

(South African J of Animal Science: 2000, 30, Supplement 1: 6-7

The chemical composition of silages produced in a Mediterranean climate

(South African J of Animal Science, 2000, 30, Supplement 1: 91-92

The effect of milk yield on some reproductive parameters of the Elsenburg Holstein and Jersey herds

(South African J of Animal Science, 2000, 30, Supplement 1: 34-35

Dynamics with Infinitely Many Time Derivatives and Rolling Tachyons

Both in string field theory and in p-adic string theory the equations of motion involve infinite number of time derivatives. We argue that the initial value problem is qualitatively different from that obtained in the limit of many time derivatives in that the space of initial conditions becomes strongly constrained. We calculate the energy-momentum tensor and study in detail time dependent solutions representing tachyons rolling on the p-adic string theory potentials. For even potentials we find surprising small oscillations at the tachyon vacuum. These are not conventional physical states but rather anharmonic oscillations with a nontrivial frequency--amplitude relation. When the potentials are not even, small oscillatory solutions around the bottom must grow in amplitude without a bound. Open string field theory resembles this latter case, the tachyon rolls to the bottom and ever growing oscillations ensue. We discuss the significance of these results for the issues of emerging closed strings and tachyon matter.Comment: 46 pages, 14 figures, LaTeX. Replaced version: Minor typos corrected, some figures edited for clarit