Motility and fertility of bovine semen stored at -79° C and -196°C

The percentage of motile spermatozoa in bovine semen frozen in ampoules and stored for 120 days either at -79° G in solid carbon dioxide-alcohol or at -196° C in liquid nitrogen was compared. The percentage motile spermatozoa was higher (P < 0.01) after 14 days' storage at -196° G than at -79° C. This difference was still apparent after 120 days' storage (P < 0.01). The transfer of semen from storage in solid carbon dioxide-alcohol to liquid nitrogen produced no change in the percentage of motile spermatozoa. However, when semen was transferred from liquid nitrogen storage to solid carbon dioxide-alcohol there was a decline in motility similar to that found at primary storage in solid carbon dioxide-alcohol. Split batches of semen stored for 90 days in solid carbon dioxide-alcohol and liquid nitrogen were used for the insemination of cows. The solid carbon dioxide-alcohol stored semen was transferred to liquid nitrogen for field storage. The 60- to 90-day N.R. rates were 70.9% for semen stored in solid carbon dioxide-alcohol and 73.5% for semen stored in liquid nitrogen.-A.S

Comparison of storage motility and fertility of chilled bovine semen extended in different diluents

Motility assessments of spermatozoa extended in two 20% egg yolk-glycine diluents (CUE and CU-16), skim milk-10% glycerol (MG) and 50% egg yolk-citrate (EYC) were compared over 12 days’ storage at 5° C.

A new formula for determining the atmospheric longwave flux at the ocean surface at mid-high latitudes

[1] The accuracy of two empirical formulae used in recent climatological studies to estimate the atmospheric longwave flux at the ocean surface from ship meteorological reports has been evaluated using research cruise measurements from the northeast Atlantic. The measurements were obtained with a pyrgeometer and corrected for differential heating of the pyrgeometer dome and shortwave transmission through the dome. The formulae tested were from Clark et al. [1974] and Bignami et al. [1995]; neither was capable of providing consistently reliable estimates of the longwave flux. Clark overestimated the mean measured longwave of 341.1 Wm(-2) by 11.7 Wm(-2), while Bignami underestimated by 12.1 Wm(-2). A new formula is developed that expresses the effects of cloud cover and other parameters on the longwave through an adjustment to the measured air temperature. The air temperature is adjusted by the amount necessary to obtain the effective temperature of a blackbody with a radiative flux equivalent to that from the atmosphere. A simple parameterization of the adjustment in terms of the total cloud amount gives longwave estimates that have an improved mean bias error with respect to the measurements of -1.3 Wm(-2). The new formula is still biased under overcast, low cloud base conditions. However, by including a dependence on dew point depression in the formula, this bias is resolved, and the mean error reduced to 0.2 Wm(- 2). The new formula has been tested using measurements made on two subsequent cruises and found to agree to within 2 Wm(-2) in the mean at middle-high latitude

The eosinophil leucocyte, a phenotypic marker of resistance to nematode parasites, is associated with calm behaviour in sheep

The hypothesis that behaviour in sheep is influenced by resistance to infections with Trichostrongylus colubriformis and Haemonchus contortus was explored. Sheep were assessed phenotypically as resistant and susceptible in four ways and thereafter, the effect of resistance on several behavioural traits was measured in an arena test. The behavioural parameters recorded for each sheep were: approach/avoidance distance; travel; number of moves; and spread. Four phenotypic groups of sheep were set up each with two subgroups: ovine lymphocyte antigen (OLA) type (subgroups SY1a type vs other types); blood eosinophil leucocyte counts (high vs low); T. colubriformis and H. contortus serum antibodies (high vs low titres) and faecal egg count (FEC) (high vs low). Only the behavioural comparison between sheep with high versus low eosinophil leucocyte count showed consistent differences that were statistically significant, although other comparisons favoured associations between OLA type SY1a, low FEC and reduced approach/avoidance distance and/or locomotor behaviour. The eosinophil leucocyte association was established on two non-overlapping test populations of sheep, with mean eosinophil leucocyte counts of 3.19 x 10/mL blood for high and 0.83 x 10/mL blood for low subgroups; results were reproduced on five separate occasions over 6 weeks to detect differences as approach/avoidance distance (P < 0.01), travel (P < 0.01), number of moves (P < 0.01), and spread (P < 0.05). High eosinophilia correlated with low FEC for the infected sheep, which identified sheep that were resistant to parasites. We concluded, therefore, that the resistant sheep were more at ease with the environment of the test than were the sheep with low eosinophil leucocyte counts. The strong association between high eosinophil leucocyte counts and behaviour is consistent with other reports which suggest that retention of normal levels of circulating eosinophil leucocytes is associated with resistance to stress

Effect of grazing sorghum (Sorghum bicolor) infected with ergot (Claviceps africana) on beef cattle

14 heifers aged 3 to 4 years (Bos indicus × Bos taurus), including 9 in the second month of pregnancy, plus 9 steers aged about 14 months (Bos taurus) were grazed on sorghum infected with C. africana ergot for 28 days. Estimated average daily dry matter intake over the trial period was 9.0 kg. Daily alkaloid intakes (mostly dihydroergosine) were estimated to be about 35 mg/head. Over the course of the trial, there was a slight decline in body weight of the heifers, which averaged 405 kg initially and 400 kg after 28 days. The weight of the steers averaged 283 initially and 295 kg after 28 days (an apparent gain of 0.4 kg/day). Plasma prolactin concentrations (whole herd) of 140 mg/litre were reduced to 79 mg/litre after 14 days of grazing and were 93 mg/litre after 28 days. These changes in steers (decrease after 14 days and increase from 14 to 28 days) were both significant. There also were reductions in mean prolactin concentrations in both pregnant and non-pregnant heifers after 14 days grazing, but these were not significant. The steers had lower prolactin concentrations than the heifers and showed a greater response to grazing. No clinical abnormalities were detected in any of the cattle