Acid-base balance parameters and a value of anion gap of arterial and venous blood in Małopolski horses

The comparative study of the acid-base balance (ABB) parameters has been performed on 20 clinically healthy mature Ma?opolski horses. An arterial blood sample from the facial artery and a sample of venous blood from the external cervical vein were colected from each animal. In the samples tested, the blood pH, pCO2, tCO2, HCO3-, concentration of Na+, K+, Cl-, and a value of the anion gap were determined. The difference among pCO2, tCO2, and HCO3- in both samples tested was statistically significant, whereas the pH of the arterial blood and the pH of the venous blood did not differ significantly. The anion gap in both types of blood did not differ significantly. Conclusions: 1) ABB parameters such as pCO2, HCO3-, and tCO2 determined in the arterial and venous blood of the Ma?opolski horses differ from each other significantly. 2) In spite of the lack of the differences between pH of the arterial and venous blood, the ABB parameters in horses should be determined in the arterial blood, because the comparative study performed proves that the analysis of the ABB parameters determined for the venous blood of a healthy horse may lead to a wrong diagnosis of the compensated respiratory acidosis. 3) The mean value of anion gap in horses aged 8-12 years amounts to 20.9 mmol/l for the arterial blood and 19.93 for the venous blood; the difference between the two values is not statistically significant.     

A formal method of determining the dietary amino acid requirements of laying‐type pullets during their growing period

1. The amino acid requirements of laying type pullets during the growing period can be estimated by measuring the growth of different components of the body and making use of nutritional constants that define the amount of each amino acid that is required for the production of the tissues being formed.

2. In this experiment, carcase analyses of each of three breeds of pullets were conducted at weekly intervals throughout the growth of the pullets, to 18 weeks of age. Measurements were made of body weight, gut‐fill and feather weight, and chemical analyses consisted of water, protein, lipid and ash measurements of both the body and the feathers. Each age group comprised 10 birds of each breed.

3. Gompertz functions accurately estimated the growth of both body protein and feather protein, to 18 weeks of age, from which the rate of growth of these two components of the body could be estimated. The mature weight of pullets was overestimated by the Gompertz growth curve, which may indicate that a pullet ceases to increase in body protein content once sexual maturity has been reached.

4. Using allometric relationships between the chemical components of the body and of feathers, all the components of growth could be estimated from the growth of body protein and feather protein. These components were then added together to determine the growth rate of the body as a whole.

5. The daily amino acid requirements for 4 functions were calculated, namely, those for the maintenance of body protein and feather protein, and for the gain in body protein and feather protein. These requirements were then summed to determine the requirement of pullets on each day of the growing period.

6. Using the ‘effective energy’ system, the amount of energy required by these pullets was calculated for each day of the growing period, from which the desired daily food intake of the pullets could be predicted. By dividing the amino acid requirement by this daily food intake it was possible to determine the concentration of amino acids that would be needed in the diet in order to meet the requirements of a pullet.

7. The results indicate that the ratio between the requirement for lysine and for methionine and cysteine changes dramatically during the growing period, negating the concept of a fixed ratio between all the amino acids during growth.

8. The above process is the first step in determining the optimal feeding programme for a population of pullets of a given genotype. The constraining effects, of the diet being offered and of the environment in which the pullets are housed, on the food intake and growth rate of each pullet have to be estimated, and such a theory can then be expanded to include all the individuals in the population. Only by the use: of simulation models can all these constraining effects be considered simultaneously.     

Modification by metyrapone of the “open period” for pre‐ovulatory LH release in the hen

1. A single injection into laying hens of 60 mg metyrapone 28 h after the final ovulation of a sequence induced increases in the plasma concentrations of LH and progesterone, followed by premature ovulation. Injection of metyrapone 8 h after ovulation, however, did not affect plasma concentrations of either LH or progesterone.

2. Injection of laying hens with 60 mg metyrapone on 5 successive days reduced the effectiveness of exogenous ACTH in increasing the plasma concentration of corticosterone and abolished the system of “ open “ and “ closed periods “ for pre‐ovulatory LH release. Thus, pre‐ovulatory LH surges and ovipositions occurred throughout the 24‐h day instead of being restricted to an 8 to 10‐h period of the day.

3. These observations suggest that changes in environmental stimuli such as light act via the adrenal gland in regulating the timing of the “ open period “ for the pre‐ovulatory release of LH in the hen.     

Relationship between contractions of the uterus and concentration of PGF2α in uterine venous blood after luteolysis in gilts

The origin and physiological significance of high pulses of prostaglandin F2α (PGF2α) in uterine venous blood that occur 2-3 days after luteolysis are not well understood. We studied the relationship between contractions of the uterus evoked by exogenous oxytocin (OT) and PGF2α concentration in uterine venous blood on day 17 of the porcine oestrous cycle. The infusion of OT into the uterine artery produced an immediate increase in the uterine intraluminal pressure (UIP) (p < 0.001) and a simultaneous elevation in PGF2α concentration in uterine venous blood (p < 0.0001). The infusion of indomethacin (IND) into the uterine artery slightly decreased PGF2α concentration in uterine venous blood, but it did not suppress uterine contraction or the rapid increase in PGF2α concentration in uterine venous blood just after OT infusion (p < 0.0001), which was lower that in gilts not treated with IND. We conclude that the spikes of PGF2α concentration in uterine venous blood occurring after OT infusion on day 17 of the porcine oestrous cycle are mainly caused by the excretion with venous blood from the remodelled uterus and that PGF2α synthesis may contribute to this. These results suggest that the high spikes in PGF2α concentration that occur 2-3 days after luteolysis in pigs, sheep, cows and mares all have a similar origin.     

Comparison between pre‐ and postnatal acid‐base status of calves and their perinatal mortality

Summary

The acid‐base status of 58 calves (all in normal anterior presentation) was determined from venous blood samples before the onset of traction and immediately after vaginal delivery.

Calves were assigned to one of three groups according to their blood pH value: group 1 ‐ normal, pH >7.2; group 2 ‐ acidotic, pH 7.2 to 7.0; group 3 ‐ severely acidotic, pH < 7.0. Before the onset of traction (i.e. during the 30 minutes following the appearance and rupture of the membranes), 43 calves (74.1%) had normal acid‐base values, 14 (24.1%) had slight acidosis, and only 1 (1.7%) had severe acidosis. At birth the three groups of calves showed the following distribution: 23 (39.7%) were normal, 29 (50%) had slight acidosis, and 6 (10.3%) had severe acidosis.

Seven calves (12. 1%) died during birth or within 48 hours after birth; 2 were normal shortly before birth, 4 were acidotic shortly before birth, and 1 was severely acidotic even before the onset of traction. Traction was significantly longer for cows that delivered severely acidotic calves compared to cows in the other two groups.     

Comparison of DL‐methionine and methionine hydroxy analogue‐free acid in broilers by using multi‐exponential regression models

1. Methionine hydroxy analogue‐free acid (MHA‐FA) was evaluated for biopotency compared to DL‐methionine in a practical diet for broiler chicks.

2. Both methionine sources were added at equimolar concentrations of 0.03, 0.07, 0.11, 0.15, 0.20 and 0.25% to the diet.

3. A non‐linear multi‐exponential regression model was used to describe the weight gain and food conversion response to supplemental sources of methionine.

4. Compared with DL‐methionine on an equimolar basis, bioefficacy of MHA‐FA was calculated at 73% from weight gain and 68% from food conversion data, respectively. This corresponds to an efficiency of Alimet® between 60 and 64% relative to DL‐methionine on a weight for weight basis.     

Effects of short‐term thyroxine administration during the laying period on egg production and moulting by Turkeys

1. Effects of thyroxine (T₄) administration on egg production, moulting and photorefractoriness in laying turkeys were determined. Thyroxine dosages of 0.075 to 2 mg/bird/d were injected IM for periods of either 2 or 3 weeks following 10 weeks of photostimulation. Control groups were administered saline vehicle.

2. Plasma T₄ concentrations were increased in a dose dependent manner by T₄ administration, while triiodothyronine (T₃) was decreased.

3. Egg production and percentage of hens in production were transiently decreased in a dose dependent manner by T₄ administration, but returned to levels similar to controls within 4 weeks of T₄ treatment termination. Moulting was stimulated in a dose‐dependent manner by T₄ administration, but was similar to controls after T₄ treatment termination. Only dosages of 2 mg/bird/d resulted in cessation of egg production and complete moulting.

4. Results indicate that although short term elevation of plasma T₄ causes cessation of egg production and moulting these effects are transient and not indicative of photorefractoriness.     

Genetic parameters of egg production,body weight and egg size in the red‐legged partridge

1. Heritability estimates of egg production, egg weight and body weight of red‐legged partridge were obtained.

2. Data from a population selected for increased egg production over four generations as well as from a random‐bred control population were available.

3. Heritability of egg number during the first production period was considerably higher than estimates for a second production period, induced by appropriate lighting.

4. Egg weight and body weight were highly heritable.     

Effects of dietary supply of arginine on urinary orotic acid excretion,growth performance and blood parameters in growing mink (Mustela vison) kits fed low‐protein diets

Effects of dietary arginine levels of 1.2%, 1.7% and 2.2% of dry matter (DM) (4.8 g/16 g N, 6.4 g/16 g N and 8.0 g/16 g N, respectively) and excess dietary lysine (6.5% in DM, 22 g/16 g N) were investigated in male mink kits fed low‐protein diets supplemented with a mixture of amino acids in the growing period during 4 weeks in July‐August. Urinary excretion of orotic acid, growth performance, feed consumption, plasma concentrations of ammonia (NH₃), orotic acid, urea and glucose were studied. The results showed that arginine is an essential nutrient for mink kits in the growing period and that excess dietary lysine antagonizes arginine. An arginine supply of 2.2% of DM (8.0 g/16 g N) resulted in minimum urinary excretion of orotic acid and a supply of 1.7% of DM (6.4 g/16 g N) prevented increased plasma concentrations of NH₃. Growth performance was negatively affected by the low protein level in all diets. The plasma concentrations of orotic acid, urea and glucose were not affected by the dietary levels of arginine.     

Broken bones in domestic fowls: Effect of husbandry system and stunning method in end‐of‐lay hens

1. The effects of age at sexual maturity, age at culling, and stunning frequency and current on the incidence of broken bones were examined in end‐of‐lay hens. In addition comparisons were made between 4 different egg‐laying breeds, and between battery, perchery and free range husbandry systems.

2. High frequency stunning (1500 Hz) caused a reduction in the incidence of broken bones compared with 50 Hz.

3. Battery birds had a higher incidence of recently broken bones in comparison with perchery and free range birds. However, there were more old breaks in the perchery and free range systems than in the battery system.

4. Breed of bird, age at sexual maturity and age at culling had no effect on the incidence of broken bones.     

The activation of the IFNβ induction/signaling pathway in porcine alveolar macrophages by porcine reproductive and respiratory syndrome virus is variable

Background

It has been recognized that the expression of type I interferon (IFNα/β) may be suppressed during infection with porcine reproductive, respiratory syndrome virus (PRRSV). This causes profound negative effects on both the innate and adaptive immunity of the host resulting in persistence of infection.

Objective

Test the effects of PRRSV infection of porcine alveolar macrophages (PAMs), the main target cell, on the expression of interferon beta (IFNβ) and downstream signaling events.

Methods

In order to examine those effects, PAMs harvested from lungs of healthy PRRSV-free animals were infected with virulent, attenuated, infectious clone-derived chimeric viruses, or field PRRS virus strains. Culture supernatants from the infected PAMs were tested for IFNβ protein expression by means of indirect ELISA and for bioactivity by a vesicular stomatitis virus plaque reduction assay. The expression of the Mx protein was assayed to ascertain signaling events.

Results

These experiments demonstrated that PRRSV does induce variably, the expression of bioactive IFNβ protein in the natural host cell. To further elucidate the effects of PRRSV infection on IFNβ signaling, Mx-1 an interferon stimulated gene (ISG), was also tested for expression. Interestingly, Mx-1 expression by infected PAMs generally correlated with IFNβ production.

Conclusion

The results of this study demonstrate that the induction of IFNβ and signaling in PAMs after PRRSV infection is variable.

     

Relation between selenium content and glutathion‐peroxidase activity in blood of cattle

Summary

To identify a simple method for assessing the selenium demand in cattle, the relationship between selenium content in whole blood and the concentration of the selenium containing enzyme glutathion peroxidase (EC 1.11. 1.9; GSH‐Px) in red blood cells was studied. On six farms with suspected low soil selenium content, blood samples were collected from groups of calves, yearlings and adults at the end of the housing period and of the grazing period.

The data obtained showed a highly significant correlation between the parameters mentioned: GSH‐Px (U/g Hb) = 3.261 * Se (μg/kg) ‐ 40.553. In growing animals there was a decline in Se supply with age, followed by a gradual recovery in heifers. This was most pronounced on some sandy soils and on peat soil.

Seasonal effects could not be demonstrated.     

Acute changes in the concentrations of prostaglandin F2α (PGF) and cortisol in uterine and ovarian venous blood during PGF-induced luteolysis in cows

Prostaglandin F2α (PGF) is considered to be the main luteolysin in cattle. We have previously demonstrated that cortisol (Cr) suppresses PGF production in non-pregnant bovine endometrium. This study was carried out to test whether exogenous PGF increases ovarian and/or uterine PGF production and to determine the temporal relationship between PGF and Cr in ovarian and uterine circulations during PGF-induced luteolysis in cows. Catheters were inserted into the ovarian vein (OV), uterine vein (UV) and jugular vein (JV) of 10 cows on Day 9 of the oestrous cycle (Ovulation = Day 0) for frequent blood collection. On Day 10, the cows were divided randomly into two groups and treated with a luteolytic dose of a PGF analogue (cloprostenol) or saline solution. Blood samples were collected at -0.25, 0, 0.25, 0.5, 1 and 2 h and then at 2-h intervals until 12 h after treatment (0 h). The basal concentrations of PGF and Cr in OV and UV plasma were not significantly different. Injection of a PGF analogue induced more than twofold increases in the levels of PGF between 0.25 and 1 h in UV plasma, but not in OV plasma. PGF increased (p < 0.05) the concentrations of Cr in OV, UV and JV plasma between 0.5 and 1 h. The Cr levels in OV, UV and JV plasma were similar. The PGF levels in UV plasma decreased after Cr reached its highest levels. The overall results suggest that the uterus rather than the ovary increases PGF production in response to PGF injection. Based on the temporal changes of PGF and Cr in the ovarian and uterine circulations, Cr may act to reduce uterine PGF production in non-pregnant cows in vivo.     

Extending the viability of emu spermatozoa during in vitro storage by manipulation of temperature and diluent potassium concentration

1. Survival of emu spermatozoa during in vitro storage is not affected by increasing the extracellular [K⁺] to the point where it does not adversely affect spermatozoa function.

2. In three experiments, the effects were studied of [K⁺] in a diluent in the range 12·5–80?mM/l on emu spermatozoa survival for up to 48?h at 5, 10 or 20°C.

3. At the end of the storage period, spermatozoa viability, motility, fertilising ability and morphology were measured.

4. In Experiment 1, spermatozoa viability and morphology were adversely affected after storage (P?M/l [K⁺] whereas spermatozoa motility decreased as [K⁺] increased from 12·5 to 80?mM/l.

5. In Experiment 2, during storage at 5°C, the spermatozoa viability was comparable among any of the diluents (standard or modified) but morphology was better (P? 6. In Experiment 3, after 48?h of storage in a diluent containing 40?mM/l of [K⁺], the spermatozoa functions were better preserved at 10°C than at 5 or 20°C.

7. It is concluded that a higher than physiological level of potassium can be used in a diluent without detrimental effect on emu spermatozoa survival during 48?h storage and that the best outcome was with storage at 10°C rather than 5 or 20°C.     

Dietary influences on the hydration and acid–base status of experimentally dehydrated dairy calves

The incorporation of oral rehydration solutions (ORS) into ‘milk meals’ is potentially an effective, time-saving method of treating diarrhoeic calves. Although milk-based ORS are effective in improving the hydration and acid–base status of healthy calves, this effect remains to be confirmed in dehydrated/diarrhoeic animals. In this study, six experimentally-dehydrated calves were fed with either milk replacer (MR) or an ORS prepared in either water (WORS) or MR (MORS). In one experiment, calves were not treated and blood samples were taken before and after feeding. Parameters of hydration status were determined and blood gas analysis was performed.Plasma volumes increased significantly following the intake of a ‘fluid meal’ whereas they remained constant in the absence of treatment. The rate of plasma volume expansion was reduced by the feeding of MR relative to WORS or MORS. In dehydrated calves, the expansion of plasma volume was more pronounced following the intake of WORS but the increase was less and plasma osmolality increased significantly following the ingestion of MORS. The acid–base status of animals improved as a result of fluid absorption, but this effect was less obvious as the experimental protocol resulted in severe dehydration and moderate acidosis. Feeding hypertonic MORS raised the plasma osmolality in dehydrated calves, and may increase the risk of hypernatraemia in diarrhoeic calves, which should therefore have ad libitum access to water when undergoing treatment with hypertonic ORS. Further research is planned to assess whether feeding ORS reconstituted in milk or MR combined with ad libitum access to water offers a practical treatment for diarrhoeic calves.     

The effect of feeding low‐protein diets to pullets from hatch to point‐of‐lay and the quantitative restriction of food during the subsequent laying period

Pullets from two commercial breeds were fed on diets of similar energy content but with 19% or 16% crude protein to 8 weeks of age and from 8 to 20 weeks of age on one of three isoenergetic diets containing either 12, 14 or 16% crude protein. At 20 weeks the birds were offered a conventional layers’ diet containing 16% crude protein either ad libitum or on a daily food intake of 100 g for a further 32 weeks.

The results indicate that with certain breeds the dietary protein levels can be lowered to approximately 16% during the o to 8‐week period and to approximately 12% during the 8 to 20‐week period without adversely affecting egg production. However, variations in the laying performance of the different breeds appear to be dependent on the amount of protein fed in the first eight weeks of life. Significant breed effects were observed throughout the experiment and although restricted feeding during the laying period substantially reduced the food intake it also had a detrimental effect on the rate of egg production and on the total weight of eggs produced.     

Effects of dietary dried baker’s yeast on the performance,egg traits and blood parameters in laying quails

This study was conducted to investigate the effects of dietary dried baker’s yeast on laying performance, egg traits and some blood parameters of quails. In the experiment a total of 342 Japanese quails (Coturnix coturnix japonica) aged ten weeks were equally divided into six groups of 57 (three replicates of 19 quails each). Six levels (0, 4, 8, 12, 16 and 20%) of dried baker’s yeast were included in isonitrogenous and isocaloric diets. The experimental period lasted 14 weeks. At the end of the experiment, there were no significant differences among the groups in body weight, feed intake, protein intake, egg production, feed efficiency, egg yolk index and egg haugh unit. Blood serum levels of total protein, triglyceride and cholesterol were not affected by dietary dried baker’s yeast. Diets containing 4 and 8% of dried baker’s yeast increased the egg weight significantly (p < 0.01). The inclusion of dried baker’s yeast at the level of 20% to the diets reduced egg shell thickness and egg albumen height. It is concluded that dried baker’s yeast can be used up to 16% in the diets of laying quails without adverse effects on the measured parameters.     

Comparative efficacy of three antibiotic products for the treatment and prevention of sub‐clinical mastitis during the dry period

Summary

The comparative efficacy of a product containing 500 mg benzathine cloxacillin (Orbenin D.C.), another product containing 100 mg nafcillin, 300 mg procaine benzylpenicillin and 100 mg dihydrostreptomycin (Nafpenzal D.C.) and a third product containing 250 mg cephalonium (Cepravin D. C.), in the elimination and prevention of mastitis due to gram‐positive microorganisms during the dry period was investigated in 1253 cows located in 14 herds in Israël.

Although more uniform results were observed after treatment with Nafpenzal D.C., differences were not found among the products with respect to the overall efficacy but differences among herds were rather large. The mean cure rate for Staphylococcus aureus quarter infections was 81.4 per cent. New S. aureus infections which occurred between drying off and post calving sampling time were found in 7.0 per cent of the quarters.

Dry period therapy reduced infection level with S. aureus from 13.5 per cent of quarters to 8.0 per cent. A similar proportional decrease was found in infection level due to non‐agalactiae Streptococcus quarter infections.     

Effects of evisceration and storage temperature on changes in meat quality of traditional farm‐fresh Turkeys

1. Conditions affecting the keeping quality of traditional farm‐fresh turkeys were investigated.

2. Storage of uneviscerated Wrolstad turkeys at 4 °C for 10 days caused no statistically significant changes in meat flavour or texture.

3. During further storage at —2 °C, however, there was a slight but significant change in flavour, which became more marked with time in birds which had been eviscerated after the initial period at 4 °C.

4. Both eviscerated and uneviscerated birds became slightly tougher during storage.

5. Initial holding at 4 °C increased the numbers of psychrotrophic bacteria on the skin by about 10³ but subsequent changes at — 2 °C were slight for uneviscerated birds.

6. Eviscerated carcases had higher counts than uneviscerated birds after storage at — 2 °C and, although ‘off’ odours were not detected, spoilage appeared to be imminent at the end of the 20‐d period.     

Biological efficacy and absorption of DL‐methionine hydroxy analogue free acid compared to DL‐methionine in chickens as affected by heat stress

1. The net absorption and the biological efficacy of DL‐methionine and of DL‐methionine hydroxy analogue free acid (MHA‐FA) were evaluated in chickens under heat stress.

2. In a growth assay, finishing broilers 21 to 42 d of age were fed on diets containing graded amounts of the two supplements; the basal diet was composed of practical ingredients.

3. From slope‐ratio analysis, equimolar efficacy of MHA‐FA relative to DL‐methionine was determined to be 83% (confidence limits 61 to 115%) from weight gain responses, and 67% (47 to 91%) from food conversion responses. This indicates that the relative efficacy of MHA‐FA is close to previous estimates of about 75% obtained under thermoneutral conditions.

4. In a balance study with caecectomised cockerels, net absorption (intake—excretion in faeces and urine) of DL‐methionine and of MHA‐FA, respectively, were determined to be 97.2 and 90.8%. The net absorption of MHA‐FA was significantly lower than that of DL‐methionine.