Hepatic lipidosis in pregnant cows on a dairy farm.

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.     

Has bovine somatotropin (BST) an effect upon drug disposition? Comparative studies in goats and cattle with sulphadimidine and antipyrine after parenteral administration of BST,zeranol and proligestone

Daily subcutaneous BST injection in lactating cows, bulls and castrated male dwarf goats did not induce significant changes in the pharmacokinetic parameters of antipyrine (AP) and sulphadimidine (SDD). Similarly, no changes were obtained after injection of slow-release BST formulations in lactating cows and non-lactating female goats. In contrast to androgenic hormones, both zeranol and proligestone had no effect upon the disposition of AP and SDD, although both synthetic hormones did induce enhanced plasma somatotropin concentrations. In goats, metabolic effects induced by zeranol and BST included significant reductions in plasma urea values, whereas plasma creatinine levels were somewhat lower after daily BST administration.     

Heparinised blood ionised calcium concentrations in horses with colic or diarrhoea compared to normal subjects

Our objectives were to 1) establish ionised calcium (ICa), C-terminal PTH and biologically active PTH (intact molecule) concentrations in blood from normal horses, 2) examine the stability of ionised calcium and acid-base values in stored equine heparinised blood and serum and 3) check the applicability of the formulas based on these parameters in certain disease states. Mean +/- s.d. % ionised calcium in heparinised blood of normal Warmbloods was 51 +/- 2.7 (n = 20) of total calcium, range 1.45-1.75 mmol/l (n = 15) at Michigan State University and 1.43-1.69 mmol/l (n = 20) at Utrecht University. Mean +/- s.d. EDTA plasma concentration for intact +/PTH in normal horses measured 0.6 +/- 0.3 pmol/l (n = 11). Both mean serum and the heparinised blood ionised calcium concentrations changed (not significantly) after 102 h storage at room temperature. Six cycles of freezing and thawing did not affect serum ionised calcium concentration significantly. Ionised calcium concentration and pH in heparinised blood of 20 normal Warmbloods were used to calculate the regression equation for the prediction of the adjusted ionised calcium concentration to a pH of 7.4. The linear regression equation found was: adjusted plasma ICa at pH 7.4 mmol/l = -6.4570 + 0.8739 x (measured pH) + 0.9944 x (measured ICa mmol/l). By means of this formula, mean adjusted ionised calcium concentration in heparinised blood calculated was 100% of the actual value given by the analyser in the normal horses. When using this formula in horses with colic or diarrhoea, mean adjusted ionised calcium concentration was underestimated by 0.2 and 0.3%, respectively. Furthermore, to adjust the measured ionised calcium concentration in heparinised blood to a pH of 7.4 in healthy as well as in 2 groups of diseased horses 2 formulas with a good prediction are now available.     

Effects of Feed in the Dry Period on Fertility of Dairy Cows Post Partum

It has been hypothesized that the decrease in fertility of dairy cows is related to the increase in milk yield and associated with fatty liver and increased vulnerability for both infection and metabolic diseases. To elucidate the mechanisms behind this complex of health and reproductive problems an Animal Model, based on overfeeding in the dry period, has been developed. In an experiment carried out in 1996 sixteen animals were fed 119 MJ/d net energy to lactation (NEL) (experimental group) and another sixteen just 49 MJ/d NEL (control group) in the last 8 weeks before parturition. During lactation the cows from both groups were given the lactation ration ad libitum. After parturition both groups differed significantly in level and duration of the NEB, in weight loss, increased concentrations of NEFAs and bHBB in the blood and TAG in the liver. Although the insulin level was lower in the experimental animals during the first week, the difference was not significant. The number of ovulations within the first 100 days pp was significant lower in the experimental group and was related to depth and duration of the NEB and the weight loss: more NEB leads to less ovulations. The interval partus-le ovulation was also significant different but related to the TAG level in the liver: more TAG leads to a longer interval. The experimental group with the fatty liver suffered more incidenses of metabolic diseases. It has been concluded that the Model leads to a severe NEB, to Fatty Liver and to more incidences of diseases. Both the NEB and the fatty liver influence the fertility of the cows pp and it can not be excluded that some diseases have an effect too. More studies are planned to unravel the factors that affect the fertility of high yielding cows.     

Some aspects of extra iron supply in veal calf fattening

Extra iron (5 ppm) in a normal commercial milk replacer given from the end of the sixth week until the end of the sixteenth week of the fattening period influenced food conversion positively without a loss in meat quality. Even when the extra iron was given to the end of the fattening period there was no perceptible improvement of the haematological status of the calf, though liver iron concentration was increased. During all the experiments no stainable iron could be found in bone marrow smears. Iron and copper concentration measured in liver biopsies appeared to give reliable information about, respectively, iron and copper status of the veal calf. In relation to the colour of the meat at slaughter the blood haemoglobin concentration during the fattening period was found to be the most reliable parameter.     

The effect of feeding pellets of different types of roughage on the incidence of lesions in the abomasum of veal calves

Pellets of three types of roughage were fed to veal calves, to determine their effect on the frequency of lesions (erosions or ulcers) of the abomasal mucosa. The number was increased in the calves fed roughage. Pellets produced from corn silage caused a greater number of lesions than pellets produced from barley straw or lucerne hay. It is concluded that the nature of the roughage plays a role in the pathogenesis of abomasal lesions.     

Intraruminal administration of milk in the calf as a model for ruminal drinking: Morphological and enzymatical changes in the jejunal mucosa

In order to develop a calf model for studying the syndrome of ruminal drinking (RD) in veal calves, three dual-fistulated calves were used to test the effect of intraruminal administration of milk replacer on the jejunal mucosa. Biopsies of the proximal jejunal mucosa were taken through a jejunal fistula and the mucosal morphology and the activities of two brush border enzymes, lactase and alkaline phosphatase, were determined.Means of villus length and brush border enzyme activities decreased during the period of intraruminal administration of milk. The hyperplastic villus atrophy in this model was similar to that found in chronic RD patients in previous studies. This could not be associated with isolation of pathogenic micro-organisms from the faeces and is probably the consequence of the intraruminal milk feeding procedure itself.Clinical recovery from the signs of RD occurred rapidly after intraruminal administration of milk ceased and was followed by restoration of villus length and brush border enzyme activities 3–4 weeks later.     

Effect of Trypanosoma vivax infection on energy and nitrogen metabolism of west African dwarf goats

A study was conducted using 32 mature 22-kg West African Dwarf Goats to measure the effect of Trypanosoma vivax infection on energy and nitrogen metabolism. Sixteen goats were infected intravenously with 14 X 10(6) T. vivax. Sixteen control goats were sham-injected. Digestibility and metabolizability of energy and N balance were measured for each goat. Heat production and energy balances were measured per treatment group from 1 wk before infection to 6 wk after infection. Goats were fed alfalfa pellets (10% above maintenance). Treated goats had a reduced (P less than .05) packed cell volume (38 to 40% before infection vs 20 to 25% 6 wk after infection) and an increased (P less than .05) rectal temperature. Log parasitemia/ml was about 6.0 to 6.2. Parasitized goats showed increased urine creatinine excretion at wk 2 postinfection. After infection, feed intake was reduced (about 15%; P less than .05) and greater variability in intake was noted. Treated and control goats had similar N output and energy output in urine. Metabolizability of energy intake was similar at 42.7 vs 42.1% in treated vs control goats, respectively. Heat production in infected goats was increased by about 15%. Treated goats lost more weight and had a lower N balance than control goats (P less than .05). The calculated maintenance energy requirement for infected goats (464 kJ ME/kg.75) was 25% greater than for control goats (375 kJ ME/kg.75).     

Variation of fiber types in the triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris of horses

The distribution of type-I and type-II fibers in 9 different parts of the musculi triceps brachii, longissimus dorsi, gluteus medius, and biceps femoris was studied to determine whether biopsies from these muscles give reliable information. All 4 investigated muscles were not homogeneous in their fiber-type distribution. Large differences existed among different muscle parts. The percentage of type-I fibers increased toward the deeper and cranial parts of the muscles. In the same zone of the gluteus muscle, differences of 30% were found for type-I fibers. Therefore, results obtained by biopsies of muscles must be interpreted with caution.