2-Mercaptoethanol influences the in vitro function of bovine peripheral blood mononuclear cells.

The effects of 2-mercaptoethanol (2-ME) on some in vitro functions of bovine peripheral blood mononuclear cells (PBMC) were examined. It was shown that 2-ME enhanced, in a dose-dependent manner, the production of antibodies to bovine coronavirus. In this test the optimal concentration of 2-ME was 50 microM. This molarity of 2-ME was also optimal for the pokeweed mitogen (PWM)-induced proliferation of PBMC obtained from the 7 cattle tested. Similarly, the spontaneous proliferation of PBMC from 4 out of these cattle was enhanced. Thus, 2-ME evoked an increase (up to 2.5 times) or a decrease (at most 10 times) of the quota between the PWM-induced and the spontaneous proliferation (stimulation index). In general, the presence of 50 microM 2-ME enhanced the in vitro production of interferon by bovine PBMC. On the contrary, the highest proliferative response of PBMC to stimulation with bovine virus diarrhoea virus was achieved in cultures without 2-ME or in cultures with 0.5 or 5 microM 2-ME. Since the effects of 2-ME varied, for different tests as well as for cattle tested, attention should be paid to the use of 2-ME in cultures of bovine PBMC.     

Grain Yield and Drought Resistance Indices of Oat Cultivars in Field Rain Shelter and Laboratory Experiments

Oat cultivars (n = 22) varying in origin were examined in laboratory and field tests at Svalöv and Ultuna, Sweden, in 1985 and 1986. Comparisons were made between drought resistance characteristics of juvenile plants and drought responses in yield of crops grown in field. By using automatic, movable rain shelters in combination with drip irrigation systems, both high and low irrigation regimes could be effected in the field experiments.
Black oat cultivars were more stable under water deficiency conditions, particularly on sandy soil. They possessed the highest drought resistance indices both in the laboratory and field. Modern white oat cultivars were found to be most drought sensitive.
Drought resistance index (DRI) and seminal root length (RL), as assessed in seedling stage, were strongly correlated with field drought susceptibility index (S). It is suggested that DRI and RL could be used as selection criteria to increase drought resistance of oats.     

The effect of mastitis on milk progesterone concentration in dairy cows

A within cow comparison was made between milk progesterone levels in healthy and mastitic quarters. Material was collected from cows with mastitis induced by bacterial inoculation, or by inoculation with bacterial endotoxin. Furthermore material from cows with spontaneous subclinical mastitis was used. Milk progesterone levels were lowered due to mastitis. However, the decrease was not large enough to cause misinterpretation of where in the oestrous cycle (luteal phase or non-luteal phase) the samples were taken.     

Germination of <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis> resting spores stimulated by a non-host plant

Plant-induced germination of Plasmodiophora brassicae resting spores was studied in a laboratory experiment. Spore reaction was analysed in nutrient solution with exudates from growing roots of different plant species – one host plant (Brassica rapa var. pekinensis) and four non-host plants (Lolium perenne, Allium porrum, Secale cereale and Trifolium pratense) – and in controls with distilled water and nutrient solution. It was found that root exudates from L. perenne stimulated spore germination more than exudates from the other plants, including those from the host plant. The effect could not be explained by differences in the nutritional composition of the solutions due to differential uptake of the plant species, or by differences in root activity, measured as exudation of soluble sugars. This is the first time such a separation of factors has been done in analysing the influence of plants on P. brassicae germination. Although stimulation of P. brassicae resting spore germination is not restricted to the presence of host plants, it seems to vary depending on the plant species.     

Sperm Distribution and Its Relation to Ovulation in Artificially Inseminated Heifers

Contents: Blood samples were taken in ten heifers every two hours during prooestrus and oestrus for determination of the LH peak, which was used to calculote the time of expected ovulation. Artificial insemination with frozen/thawed semen was performed at different times from the beginning of oestrus and the animals were slaughtered two, twelve or 24 hours after insemination. The genital tract was flushed and the spermatozoa recovered from the flushing solution by microscopic investigation. Heifers slaughtered two hours after insemination and more than 19 hours before ovulation had more spermatozoa in the uterotubal junction (UTJ) than in the isthmus and ampulla. This sperm distribution differed from that in the other animals. In animals which were slaughtered closer to ovulation and in those who had already ovulated at slaughter, approximately the same number of spermatozoa were recovered from the UTJ and isthmus and only a few spermatozoa were recovered from the ampulla. Motile spermatozoa were found in both the isthmus, UTJ and uterus at two and twelve hours after insemination and approximately ten hours before ovulation. Their number decreased with time but some motile spermatozoa were also recovered 24 hours after insemination and after ovulation. The distribution of spermatozoa in the oviducts ipsi-and contralateral to the corpus haemorrhagicum-bearing ovary was compared in heifers that had ovulated. There were no differences in the number of oviductal segments containing spermatozoa, nor were there any differences within animal in the number of spermatozoa in the oviducts. It was concluded that ovulation does not seem to cause great changes in the distribution of spermatozoa in the oviducts. Inhalt: Spermienverteilung und deren Beziehung zur Ovulation bei kunstlich besamten Jungrindern Von 10 Färsen wurden wahrend des Diöstrus und Östrus Blutproben im Abstand von 2 Std. entnommen, um den LH-Gipfel festzustellen. Dieser wurde jür die Bestimmung des erwarteten Ovulationstermins herangezogen. Inseminationen mit Gefriersperma wurden von Brunstbeginn an in verschiedenen Intervallen vorgenommen. Die Tiere wurden 2, 12 oder 24 Std. nach der Besamung getötet, die Geschlechtsorgane gespült und die Spermien in den Spülflüssigkeiten mikroskopisch nachgewiesen. Färsen, die 2 Std. nach der Besamung und mehr als 19 Std. vor der Ovulation getötet wurden, hat-ten mehr Spermien im Ostium uterinum des Eileiters (OU) als im Isthmus und Ampulle. Diese Verteilung war von jener der anderen Tiere verschieden. Tiere, die kürzere Zeit vor der Ovulation getötet wurden, oder bei der Schlachtung schon ovuliert hatten, zeigten etwa dieselbe Anzahl von Spermien in OU und Isthmus, in der Ampulle wurden nur wenig Spermien gefunden. Bei Färsen, die ovuliert hatten, wurde die Sper-mienverteilung in den ipsi- und contralateralen Eileitern zum Corpus haemowhagicum des Ovars verglichen. Die Spermienxahlen in den Eileitersegmenten waren nicht verschieden und auch im rechten und linken Eileiter gleich. Es wurde gefolgert, daβ die Ovulation keinen groβen Einfluβ auf die Spermienverteilung in den Eileitern bewirkt.     

Consumer reactions to boar meat - A reviewRéactions des consommateurs à la viande de porcs mâles entiers-une revueVerbraucherreaktionen auf Eberfleisch — ein Übersichtsreferat

Over the last ten years, consumer reactions to boar meat have been studied in nine experiments performed in six European countries. In these different studies, conditions have differed with regard to experimental design, proportions of tainted boars and products tested. The proportions of consumers judging the odour of the tested boar meat to be less pleasant than that of normal pig meat has mainly varied from about 5 to 35%. This should be compared with 3–10% for meat tested from gilts and castrates. The results differ between countries and also between products. The most favourable results have been obtained for cured bacon, cooked ham and sausage. The conclusion must be drawn that most boar meat would be accepted by consumers. Further research should be directed to finding a reliable screening test for sorting out tainted boar carcasses.     

Repeated post-exercise administration with a mixture of leucine and glucose alters the plasma amino acid profile in Standardbred trotters

Background

The branched chain amino acid leucine is a potent stimulator of insulin secretion. Used in combination with glucose it can increase the insulin response and the post exercise re-synthesis of glycogen in man. Decreased plasma amino acid concentrations have been reported after intravenous or per oral administration of leucine in man as well as after a single per oral dose in horses. In man, a negative correlation between the insulin response and the concentrations of isoleucine, valine and methionine have been shown but results from horses are lacking. This study aims to determine the effect of repeated per oral administration with a mixture of glucose and leucine on the free amino acid profile and the insulin response in horses after glycogen-depleting exercise.

Methods

In a crossover design, after a glycogen depleting exercise, twelve Standardbred trotters received either repeated oral boluses of glucose, 1 g/kg body weight (BW) at 0, 2 and 4 h with addition of leucine 0.1 g/kg BW at 0 and 4 h (GLU+LEU), or repeated boluses of water at 0, 2 and 4 h (CON). Blood samples for analysis of glucose, insulin and amino acid concentrations were collected prior to exercise and over a 6 h post-exercise period. A mixed model approach was used for the statistical analyses.

Results

Plasma leucine, isoleucine, valine, tyrosine and phenylalanine concentrations increased after exercise. Post-exercise serum glucose and plasma insulin response were significantly higher in the GLU+LEU treatment compared to the CON treatment. Plasma leucine concentrations increased after supplementation. During the post-exercise period isoleucine, valine and methionine concentrations decreased in both treatments but were significantly lower in the GLU+LEU treatment. There was no correlation between the insulin response and the response in plasma leucine, isoleucine, valine and methionine.

Conclusions

Repeated post-exercise administration with a mixture of leucine and glucose caused a marked insulin response and altered the plasma amino acid profile in horses in a similar manner as described in man. However, the decreases seen in plasma amino acids in horses seem to be related more to an effect of leucine and not to the insulin response as seen in man.