Circadian variations of plasma renin activity (PRA), aldosterone and electrolyte concentrations in plasma in pregnant and non-pregnant goats

Steroid hormonal endpoints in goats carrying single or twin fetuses reared in semi-extensive systems

The study provides baseline data regarding 17- β -estradiol (E 2 ), progesterone (P 4 ), and cortisol profile of 30 Nicastrese goats during different physiological periods. Animals were evaluated monthly from the pre-mating period (non-pregnant), during pregnancy, and from 30 to 105 d of lactation. The effects of single or twin births and the kid's sex were also considered. Serum E 2 , P 4 , and cortisol concentrations were measured using immunoenzymatic assay kits. The highest concentrations of E 2 and P 4 ( P < 0.0001 ) were found during pregnancy and their lowest values ( P < 0.0001 ) in the non-pregnant period. E 2 was negatively correlated with P 4 ( r = - 0.41 ; P < 0.01 ) during lactation. The mothers with twin kids showed the highest concentration of P 4 ( P < 0.04 ) at >  95-115 d of gestation and the lowest of E 2 ( P < 0.04 ) at >  50-70 d of lactation. Pregnant goats carrying male kid(s) presented the highest E 2 concentrations ( P < 0.02 ) at >  130-150 d of gestation. Different physiological conditions induced a temporal relationship with the endocrine profile in Nicastrese goats. Understanding the effects of single or twin fetuses on the gestation and lactation will also be helpful to improve the managemental approach for the health of mothers and their kids.

Density-Dependent Spacing Behaviour and Activity Budget in Pregnant, Domestic Goats (Capra hircus)

Very little is known about the spacing behaviour in social groups of domestic goats (Capra hircus) in the farm environment. In this experiment, we studied interindividual distances, movement patterns and activity budgets in pregnant goats housed at three different densities. Norwegian dairy goats were kept in stable social groups of six animals throughout pregnancy at 1, 2 or 3 m² per individual and their spacing behaviours (i.e. distance travelled, nearest and furthest neighbour distance) and activity budgets (e.g. resting, feeding, social activities) were monitored. Observations were made in the first, second and last thirds of pregnancy in the mornings, at noon and in the afternoons of each of these phases (4.5 hours per observation period). The findings show that goats held at animal densities of 2 and 3 m² moved longer distances when they had more space per animal and kept larger nearest and furthest neighbour distances when compared to the 1 m² per animal density. Less feeding activity was observed at the high animal density compared to the medium and low density treatments. The phase of gestation also had an impact on almost all behavioural variables. Closer to parturition, animals moved further distances and the increase in nearest and furthest neighbour distance was more pronounced at the lower animal densities. During the last period of gestation, goats spent less time feeding and more on resting, social behaviours and engaging in other various activities. Our data suggest that more space per goat is needed for goats closer to parturition than in the early gestation phase. We concluded that in goats spacing behaviour is density-dependent and changes with stages of pregnancy and activities. Finally, the lower density allowed animals to express individual preferences regarding spacing behaviour which is important in ensuring good welfare in a farming situation.

Longitudinal study of the renin angiotensin aldosterone system in purebred Spanish broodmares during pregnancy

During pregnancy, the coordinated interaction of the components of the renin-angiotensin-aldosterone system (RAAS) plays a vital role in accommodating the cardiovascular, haemodynamic and haematological needs imposed by foetal development and the placenta. This significantly influences the birth weight of the neonate and foetal viability. Although the evolution of each of the components of this system has been widely described in various species, it has not yet been clarified in the mare. Thus, the objectives of the present research were: 1) to establish reference values for renin (REN), angiotensin II (ANG-II) and aldosterone (ALD) concentrations in Spanish broodmares, and 2) to analyse the evolution of the aforementioned components during pregnancy. Thirty-one Purebred Spanish broodmares aged between 5 and 15 years old were studied for 11 months of pregnancy and compared to a control group composed of 11 non-pregnant Spanish mares. Morning venous blood samples were drawn on a monthly basis during pregnancy and pre-treated to prevent degradation until subsequent analysis. Serum REN, ANG-II and ALD concentrations were analysed by competitive immunoassay. This study found that pregnancy in Purebred Spanish broodmares is characterised by a gradual increase in REN concentrations, variable fluctuations in ALD concentrations, and no significant modifications in ANG-II concentrations. These results could provide potentially valuable information in understanding the physiological basis of the RAAS in mares, since we have been able to establish specific reference ranges for these components, as well as obtaining information on their evolution during pregnancy. As is often the case in other animal species, the increase in RAAS activity is a natural physiological process that occurs during pregnancy in Spanish broodmares. This may also be related to certain metabolic and hormone responses that contribute to the control of homeostasis in pregnant mares.

A review of the renal system and diurnal variations of renal activity in livestock

Kidneys are the main organs regulating water-electrolyte homeostasis in the body. They are responsible for maintaining the total volume of water and its distribution in particular water spaces, for electrolyte composition of systemic fluids and also for maintaining acid-base balance. These functions are performed by the plasma filtration process in renal glomeruli and the processes of active absorption and secretion in renal tubules, all adjusted to an 'activity-rest' rhythm. These diurnal changes are influenced by a 24-hour cycle of activity of hormones engaged in the regulation of renal activity. Studies on spontaneous rhythms of renal activity have been carried out mainly on humans and laboratory animals, but few studies have been carried out on livestock animals. Moreover, those results cover only some aspects of renal physiology. This review gives an overview of current knowledge concerning renal function and diurnal variations of some renal activity parameters in livestock, providing greater understanding of general chronobiological processes in mammals. Detailed knowledge of these rhythms is useful for clinical, practical and pharmacological purposes, as well as studies on their physical performance.