Effect of feeding rumen‐protected rice bran on mineral status of non‐lactating dairy heifers

Adapting Ca homeostasis of dairy cows before calving can prevent milk fever. Rice bran, treated with formaldehyde to prevent ruminal degradation of phytic acid, was fed to heifers to study its effect on Ca homeostasis. For 3 weeks 18 heifers were supplemented 3 kg of two feeds: placebo (PF) and rice bran (RBF), defining three treatments: control (CRT), low dose (LD) and high dose (HD). In weeks 1 and 3, all animals received 3 kg of PF and in week 2: CRT received 3 kg of PF, LD received 1.5 kg of PF and 1.5 kg of RBF and HD received 3 kg of RBF. Treatments did not affect dry matter intake (DMI). Feed intakes and growth rates indicated that all heifers had nutritional requirements that exceeded their Ca intakes. Serum Ca, urinary Ca, calcitriol or hydroxyproline remained unaffected. Urinary Ca was consistently low indicating high renal Ca reabsorption, which is indicative of insufficient Ca supply. Rice bran feed influenced P, Mg and Zn intakes and serum and urine presence of these minerals. Most heifers already presented an upregulated Ca metabolism, being inadequate to study adaptive changes in Ca homeostasis of multiparous dry cows. This metabolic difference can be explanatory to the very low susceptibility of heifers to milk fever, further supporting the induction of homeostatic adaptation before calving to prevent milk fever. Rice bran feed did not reduce DMI, and was not detrimental to P, Mg or Zn status.     

Pathology of experimentally-induced, acute toxoplasmosis in macropods

SUMMARY Thirteen Tammar wallabies (Macropus eugenii) were dosed orally with 500, 1000 or 10 000 oocysts of Toxoplasma gondii, as part of a vaccination trial. Eleven animals died of acute toxoplasmosis 9 to 15 days after challenge. The lesions were similar in all animals, consisting of foci of necrosis and inflammation in the intestines, lymphoid tissue, adrenal cortex, heart, skeletal muscle and brain, and severe generalised pulmonary congestion and oedema. Free and intracellular tachyzoites of Toxoplasma were associated with the lesions. The remaining 2 animals had shown no signs of disease when euthanased four months after challenge. Small, focal, non-suppurative inflammatory lesions were seen in brain, heart and skeletal muscle of these animals and chronic Toxoplasma infection was confirmed by mouse inoculation.     

Physiological effects of experimental verminous bronchitis in Friesian calves.

Pulmonary function values were measured in five Friesian calves of five months of age during the patent phase of an experimental moderate lungworm infection and were compared with the pulmonary function values recorded in four control animals. All the nine calves were free of any previous challenge with Dictyocaulus viviparus and were submitted to the same standardized conditions of body conformation, housing, feeding and procedures for pulmonary function testing. A significant increase of respiratory rate, minute ventilation, total pulmonary resistance and power of breathing and a significant decrease of tidal volume, dynamic lung compliance and PaO2 were observed in the infested animals. The absolute intrapleural pressure values were also significantly more negative. The conclusions of the statistical analysis were almost identical when predicted instead of measured pulmonary function values were used in the control group. The clinical, functional and pathological findings in the infested animals were all consistent with the picture of a lower airway obstructive disease.     

Antagonistic activities of atipamezole, 4-aminopyridine and yohimbine against medetomidine/ketamine-induced anaesthesia in cats

The objectives of this trial were to determine the ability of atipamezole, 4-aminopyridine and yohimbine to reverse the anaesthetic effects of a combination of medetomidine and ketamine in cats. Forty healthy cats were anaesthetised with 80 micrograms/kg medetomidine combined with 5 mg/kg ketamine. Thirty minutes later atipamezole (200 or 500 micrograms/kg), 4-aminopyridine (500 or 1000 micrograms/kg) or yohimbine (250 or 500 micrograms/kg) were injected intramuscularly. The doses of antagonists were randomised, so that each dose was administered to five cats, and 10 cats were injected only with physiological saline. Atipamezole clearly reversed the anaesthesia and bradycardia induced by medetomidine and ketamine. The mean (+/- sd) arousal times were 28 (+/- 4.7), 5.8 (+/- 1.8) and 7 (+/- 2.1) minutes in the placebo group, and the groups receiving 200 and 500 micrograms/kg atipamezole, respectively. The heart rates of the cats receiving 200 micrograms/kg atipamezole rapidly returned to values close to the initial ones, but 15 minutes after the injection of 500 micrograms/kg atipamezole a significant tachycardia was observed. All the cats showed moderate signs of ataxia during the recovery period. A dose of 500 micrograms/kg yohimbine also clearly reversed the anaesthetic effects of medetomidine/ketamine but 250 micrograms/kg was not effective. The dose of 500 micrograms/kg allowed a smooth recovery with no particular side effects except for some signs of incomplete antagonism of the ketamine effects, ie, ataxia and muscular incoordination. With 4-aminopyridine there were no statistically significant effects on the recovery, or the heart and respiratory rates of the cats anaesthetised with medetomidine/ketamine.     

Heat balance characteristics of limit-fed growing pigs of several breeds kept in groups at and below thermal neutrality

The lower critical temperature (Tcr) and thermoregulatory heat production below Tcr were studied in Norwegian Landrace (N), Finnish Landrace (F), Dutch Landrace (D), and Great Yorkshire (Y) barrows. Animals, weighing 26 kg at the start, were kept in groups for 18, 2-d periods in climate respiration chambers at environmental temperatures (Tenv) between 11 and 26 degrees C. Feeding level of animals in a group was 93 g.kg-.75.d-1 (2.5 times maintenance) and based on mean BW. Great Yorkshire pigs had a higher growth rate and a lower feed to gain ratio than Landrace pigs. Production characteristics of Landrace breeds were similar. The derived Tcr of the breeds was between 18.0 and 20.4 degrees C, the lower value associated with Y pigs and the higher value with F pigs. Thermoregulatory heat production was 6.4 to 11.9 kJ.kg-.75.d-1.degrees C-1 and did not differ between breeds. Radiant surface temperature (Trs) of pigs increased by .4C degrees (= bTrs) when Tenv was raised by 1.0 C degrees between 11 and 26 degrees C. In D pigs, bTrs was higher than in other pigs. Radiant surface temperature was related to backfat thickness; bTrs was increased with greater backfat thickness.     

Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during a 6-day storage period

The effects of a 6-day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid compound diets were: liquid grower diet (LGD) and liquid finisher diet (LFD). The loss of corrected dry matter after a 6-day storage, expressed in relation to the initial content, was 1.9, 6.2, 9.6, 4.6 and 4.2% for LWS, PSP, CW, LGD and LFD, respectively. During storage, the total amount of starch decreased 2.7, 24.0, 28.1 and 33.3% for LWS, PSP, LGD and LFD, respectively. The total amount of lactose decreased 23.5% for CW. The gross energy value of the products did not change remarkably during the 6-day storage period; gross energy losses being less than 3% of the initial gross energy content.     

Factors influencing thermal losses in non-ruminants: A reviewFacteurs agissant sur les pertes de chaleur chez les non ruminantsFaktoren die die Wärmeverluste bei Nicht-Wiederkäuern beeinflussen

Heat production results from the many metabolic processes occurring within the animal. In practice it has been customary and convenient to partition the animal's thermal losses into that associated with the maintenance of energy equilibrium and that originating from tissue deposition, i.e. the heat increment. The extent to which these components vary is dependent upon various animal, nutritional, environmental and behavioural factors and their relevance is discussed, particularly in relation to the extent to which they modify the animal's energy requirement for maintenance and the energetic efficiency of protein and fat deposition. These considerations are of importance because they are a necessary requisite for the calculation of dietary requirements for specific animal performance and in the evaluation of feeding standards and systems.     

Required thermal thresholds during transport of animals

Summary

Conditions (total complex of stressors) during the transport of animals vary strongly between and within transports. Adverse climatic conditions are stressors that animals have to face during transport. The thermoregulation of animals is discussed with respect to threshold values for optimal climatic conditions. These thermal thresholds depend on animal related factors and environmental conditions. The specific impact of transport conditions, such as food and water deprivation, high stocking density, high humidity and high air velocity, on thermal thresholds are described.