Changes in the metabolic profile of pregnant ewes to an acute feed restriction in late gestation

Comparison of blood ΒHBA measurement devices for diagnosis of subclinical pregnancy toxaemia in sheep: A field study

Pregnancy toxaemia is a serious disease that occurs during the last trimester of pregnancy in sheep. Yet, in most cases, the disease may have a subclinical course. This study was aimed at comparing blood βHBA measurement devices for diagnosis of subclinical pregnancy toxaemia in late pregnant sheep. In the study, a total of 50 blood samples were collected from Romanov (n = 30) and cross-bred Hamdani (n = 20) sheep. Blood βHBA levels were measured using TaiDoc TD-4235 and CentriVet βHBA hand-held meter. Randox βHBA (Ranbut) assay was used as a reference laboratory method to compare hand-held meters. βHBA value of 0.8 mmol/L was set as the cut-off value for diagnosis of subclinical pregnancy toxaemia. Statistical analyses were carried out using Minitab 21 and Jamovi software. In the study, the correlation of Randox-TaiDoc TD-4235 and Randox-CentriVet was .822 (p < .001) and .728 (p < .001), respectively. Based on the Ranbut assay, nine ewes out of 50 were diagnosed with subclinical pregnancy toxaemia. Specificity (detection of healthy ewes) and sensitivity (detection of ewes with subclinical pregnancy toxaemia) for TaiDoc TD-4235 and CentriVet hand-held meters were 100%, 77.8%, and 100%, 66.7%, respectively. In the receiver operating characteristic (ROC) analysis, areas under the ROC curve (AUC) were 0.976 and 0.920 for TaiDoc and CentriVet, respectively. Bland-Altman analysis revealed a bias of 0.092 mmol/L for TaiDoc and a bias of 0.132 mmol/L for CentriVet. TaiDoc hand-held meter shows a better correlation with the Randox Ranbut assay and greater sensitivity compared to the CentriVet hand-held meter. In conclusion, both TaiDoc and CentriVet hand-held meters can be securely used in the diagnosis of subclinical pregnancy toxaemia in sheep. For these reasons, subclinical pregnancy toxaemia and these devices will be evaluated within the scope of herd management programme in the sheep industry. It should also be taken into account that these conditions will affect the future fertility of the mother and offspring.

Pregnancy Toxemia Therapeutic Options

This review covers the treatment options for pregnancy toxemia in small ruminants. Clinical assessment and detection of underlying metabolic and electrolyte derangements direct resuscitation efforts and provide prognostic indications. Treatment programs are dependent on producer goals and case specifics. Options include oral glucogenic precursors (eg, propylene glycol, glycerol), intravenous glucose solutions, insulin, and other supportive care measures. Induction of parturition or C-section is often carried out to minimize ongoing energy deficits, with variable survival rates. Prolonging gestation to maximize fetal viability often requires intensive care in a hospital setting and carries significant risk to both dam and offspring.

Extensive Sheep and Goat Production: The Role of Novel Technologies towards Sustainability and Animal Welfare

Simple Summary

New technologies have been recognized as valuable in controlling, monitoring, and managing farm animal activities. It makes it possible to deepen the knowledge of animal behavior and improve animal welfare and health, which has positive implications for the sustainability of animal production. In recent years, successful technological developments have been applied in intensive farming systems; however, due to challenging conditions that extensive pasture-based systems show, technology has been more limited. Nevertheless, awareness of the available technological solutions for extensive conditions can increase the implementation of their adoption among farmers and researchers. In this context, this review addresses the role of different technologies applied to sheep and goat production in extensive systems. Examples related to precision livestock farming, omics, thermal stress, colostrum intake, passive immunity, and newborn survival are presented; biomarkers of metabolic diseases and parasite resistance breeding are discussed.

Abstract

Sheep and goat extensive production systems are very important in the context of global food security and the use of rangelands that have no alternative agricultural use. In such systems, there are enormous challenges to address. These include, for instance, classical production issues, such as nutrition or reproduction, as well as carbon-efficient systems within the climate-change context. An adequate response to these issues is determinant to economic and environmental sustainability. The answers to such problems need to combine efficiently not only the classical production aspects, but also the increasingly important health, welfare, and environmental aspects in an integrated fashion. The purpose of the study was to review the application of technological developments, in addition to remote-sensing in tandem with other state-of-the-art techniques that could be used within the framework of extensive production systems of sheep and goats and their impact on nutrition, production, and ultimately, the welfare of these species. In addition to precision livestock farming (PLF), these include other relevant technologies, namely omics and other areas of relevance in small-ruminant extensive production: heat stress, colostrum intake, passive immunity, newborn survival, biomarkers of metabolic disease diagnosis, and parasite resistance breeding. This work shows the substantial, dynamic nature of the scientific community to contribute to solutions that make extensive production systems of sheep and goats more sustainable, efficient, and aligned with current concerns with the environment and welfare.

Determination of natural antibodies, beta-hydroxybutyric acid, and non-esterified fatty acid levels in the serum of peripartum Tuj and Hemşin sheep

Background and Aim:

Many metabolic and immunological changes occur during the transition period. Innate immunity plays an important role against to infections and natural antibodies (NAb) are important in immunity. This study aims to determine a connection between serum NAb titers, beta-hydroxybutyric acid (BHBA), and non-esterified fatty acid (NEFA) concentrations in Tuj and Hemşin sheep during the peripartum period.

Materials and Methods:

Serum NAb, BHBA, and NEFA levels were determined from the blood samples collected from Tuj and Hemşin sheep on days 30 and 15 before birth, on the day of birth (day 0), and on days 15 and 30 after birth.

Results:

NAb titers were found to be higher in Tuj than in Hemşin sheep (p<0.001). No statistically significant difference was found in serum BHBA concentrations of both breeds on all sampling days (p>0.05). The serum NEFA level was lower in Tuj sheep in the last 15 days of pregnancy compared to Hemşin sheep (p<0.05), while no difference was found in samples collected at the other time points.

Conclusion:

This study indicated that serum NAb titers significantly changed in Tuj and Hemşin sheep during the transition period. Serum BHBA and NEFA concentrations increased during the last stages of pregnancy and decreased after birth. Based on these findings, it is suggested that the immunological status could vary by the breed of sheep or various factors that affect the sheep’s metabolic state.

Caffeine: A potential strategy to improve survival of neonatal pigs and sheep

Caffeine is commonly used to treat pre-and postnatal injuries, including apnoea in premature infants, as well as neurological impairment caused by hypoxia or asphyxiation often associated with difficult birthing. As an adenosine antagonist, caffeine is metabolised rapidly and transported into many tissues. Caffeine stimulates the brain respiratory centre, improving respiratory function in immature infants or neonates, provides neuroprotection to the fetal brain, and initiates non-shivering thermoregulation increasing metabolic rates. Recently, potential benefits of caffeine for animal production have been investigated. This has particularly occurred in pig production, where large litters are associated with relatively long parturition durations, and piglets born near the end of the parturition period have an increased risk of mortality due to asphyxia-related birthing injury. Similarly, in sheep, dystocia or prolonged parturition is a significant problem, where neonatal injury, dystocia and death in utero contributes to approximately 46 % of lamb mortalities. Within these two livestock production systems, large prevalence's of neonatal mortality is a persistent issue contributing to lost revenue, as well as being a significant animal welfare concern. Pre-partum maternal caffeine supplementation is a promising strategy to reduce neonatal mortality; however, there needs to be refinement of appropriate quantities administered, duration and administration pathway to provide producers with an efficient and cost-effective method to reduce mortality rates and increase production output. The information in this review details effects, benefits and important considerations regarding caffeine use in animal production, and identifies areas of limited knowledge where further research is needed.

Lipid metabolism is altered in maternal, placental, and fetal tissues of ewes with small for gestational age fetuses†

Nutrient restriction (NR) has the potential to negatively impact birthweight, an indicator of neonatal survival and lifelong health. Those fetuses are termed as small for gestational age (SGA). Interestingly, there is a spectral phenotype of fetal growth rates in response to NR associated with changes in placental development, nutrient and waste transport, and lipid metabolism. A sheep model with a maternal diet, starting at Day 35, of 100% National Research Council (NRC) nutrient requirements (n = 8) or 50% NRC (n = 28) was used to assess alterations in fetuses designated NR SGA (n = 7) or NR NonSGA (n = 7) based on fetal weight at Day 135 of pregnancy. Allantoic fluid concentrations of triglycerides were greater in NR SGA fetuses than 100% NRC and NR NonSGA fetuses at Day 70 (P < 0.05). There was a negative correlation between allantoic fluid concentrations of triglycerides (R2 = 0.207) and bile acids (R2 = 0.179) on Day 70 and fetal weight at Day 135 for NR ewes (P < 0.05). Bile acids were more abundant in maternal and fetal blood for NR SGA compared to 100% NRC and NR NonSGA ewes (P < 0.05). Maternal blood concentrations of NEFAs increased in late pregnancy in NR NonSGA compared to NR SGA ewes (P < 0.05). Protein expression of fatty acid transporter SLC27A6 localized to placentomal maternal and fetal epithelia and decreased in Day 70 NR SGA compared to 100% NRC and NR NonSGA placentomes (P < 0.05). These results identify novel factors associated with an ability of placentae and fetuses in NR NonSGA ewes to adapt to, and overcome, nutritional hardship during pregnancy.

Validation of a handheld β-hydroxybutyrate acid meter to identify hyperketonaemia in ewes

Background

The end of pregnancy is the period with the highest risk of occurrences of ketosis and pregnancy toxemia due to fat mobilization and increasing non-esterified fatty acids in the liver which are converted in ketone bodies, mainly β-hydroxybutyrate acid (BHB). This ketone body may also become elevated in the bloodstream. The present study validates the use of a handheld meter for determining the blood concentration of BHB and ascertaining the predictive value and accuracy of BHB measurements in diagnosing hyperketonaemia in ewes.

Methods

A total of 19, non-pregnant, crossbred ewes were subjected to 2 h of intravenous infusion of a saturated BHB solution. Over 6 h of evaluation, 247 blood samples were obtained in 13 sampling moments. The BHB concentration was measured by an enzymatic colorimetric method in an automated biochemical analyzer (gold-standard) and by a handheld meter using an electrochemical enzyme technique.

Results

There was a high correlation between both methods (r = 0.98; P < 0.001). Considering the blood BHB concentrations range 0.8–1.6 mmol/L for moderate ketosis the handheld meter presented sensitivity and specificity of 0.98 and 0.81, respectively. For severe ketosis (BHB ≥ 1.6 mmol/L) sensitivity and specificity were 0.99 and 0.75, respectively. Thus, the handheld device can be useful for diagnoses of cases of mild or severe pregnancy toxemia at field conditions.

Changes in cardiac biomarkers in goats naturally affected by pregnancy toxemia

Pregnancy toxemia (PT) is considered one of the most common metabolic diseases with high impact on the production of small ruminants. The objective of this study was investigate possible myocardial damage in goats affected with PT by the determination of serum myocardial biomarkers CK-MB and cTnI. A total of 44 goats affected with PT, and 10 apparently healthy goats (control group or CG) were used in the study. In goats with PT, the serum concentrations of cTnI (0.43 ng/mL) were significantly higher than that in CG goats (0.06 ng/mL). Although CK-MB showed no significant difference, it was approximately three times higher in animals with PT. The serum concentrations of insulin were significantly lower in PT goats (5.03 ppmol/L) compared to CG goats (10.66 pmol/L). The serum concentrations of cortisol in PT goats (155.41 nmol/L) were significantly higher than that in CG goats (36.58 nmol/L). Results of this study indicate that a clinically significant myocardial damage might occur in goats affected with PT leading to significant elevations in values of cTnI and CK-MB. Therefore, these parameters could be used as a potential prognostic indicator in goats affected with this important disease.

PPARA/RXRA signalling regulates the fate of hepatic non-esterified fatty acids in a sheep model of maternal undernutrition

Maternal undernutrition during late gestation accelerates body fat mobilization to provide more energy for foetal growth and development, which unbalances metabolic homeostasis and results in serious lipid metabolism disorder. However, detailed regulatory mechanisms are poorly understood. Here, a sheep model was used to explore the regulatory role of PPARA/RXRA signalling in hepatic lipid metabolism in undernutrition based on RNA sequencing and cell experiments. KOG function classification showed that lipid transport and metabolism was markedly altered in an undernourished model. In detail, when compared with the controls, fatty acid transport and oxidation and triglyceride metabolism were up-regulated in an undernourished model, while fatty acid synthesis, steroid synthesis, and phospholipid metabolism were down-regulated. Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis demonstrated that PPARA/RXRA signalling pathway was altered. Moreover, PPARA signalling associated genes were positively correlated with hepatic non-esterified fatty acid (NEFA) levels, while retinol metabolism associated genes were negatively correlated with blood beta-hydroxybutyric acid (BHBA) levels. Results of primary hepatocytes showed that NEFAs could activate PPARA signalling and facilitate fatty acid oxidation (FAO) and ketogenesis, while BHBA could inhibit RXRA signalling and repress FAO and ketogenesis. Excessively accumulated NEFAs in hepatocytes promoted triglyceride synthesis. Furthermore, activation of PPARA/RXRA signalling by WY14643 and 9-cis-retinoic acid could enhance FAO and ketogenesis and reduce NEFAs accumulation and esterification. Our findings elucidate the regulatory mechanisms of NEFAs and BHBA on lipid metabolism as well as the potential role of the PPARA/RXRA signalling pathway in hepatic lipid metabolism, which may contribute to exploring new strategies to maintain lipid metabolic homeostasis in human beings.

Maternal undernutrition induces fetal hepatic lipid metabolism disorder and affects the development of fetal liver in a sheep model

Undernutrition accelerates body fat mobilization to alleviate negative energy balance, which disrupts homeostasis of lipid metabolism in maternal liver. However, little is known about its effect on fetal metabolism and development. Here, a sheep model was used to explore whether maternal undernutrition induces fetal lipid metabolism disorder and further inhibits fetal hepatic development. Twenty pregnant ewes were either fed normally or restricted to 30% level for 15 d, after which fetal hepatic samples were collected to conduct transcriptome, metabolome, histomorphology, and biochemical analysis. Results showed that maternal undernutrition altered the general transcriptome profile and metabolic mode in fetal liver. Fatty acid oxidation and ketogenesis were enhanced in fetal livers of undernourished ewes, which might be promoted by the activated peroxisome proliferator-activated receptor α signaling pathway, whereas cholesterol, steroid, and fatty acid synthesis were repressed. Maternal undernutrition increased triglyceride synthesis, decreased triglyceride degradation, and inhibited phospholipid degradation and synthesis in fetal liver. In addition, our data revealed that maternal undernutrition extremely inhibited DNA replication, cell cycle progression, and antiapoptosis and broke the balance between cell proliferation and apoptosis in fetal liver, indicating that maternal undernutrition affects the growth and development of fetal liver. Generally, these findings provide evidence that maternal undernutrition during pregnancy disturbs fetal lipid metabolism and inhibits fetal hepatic development in sheep, which greatly contribute to the further study of fetal metabolism and development in human beings.-Xue, Y., Guo, C., Hu, F., Zhu, W., Mao, S. Maternal undernutrition induces fetal hepatic lipid metabolism disorder and affects the development of fetal liver in a sheep model.

Effect of diet and type of pregnancy on plasma metabolic response in sheep and its further effect on lamb performance

This trial evaluated the individual and interactional effects of diet and type of pregnancy (twin or single) on plasma metabolic response in ewes and their lambs from late pre-partum to late post-partum. Thus, a flock of 18 Ile de France breed sheep, consisting of 8 twin-bearing and 10 single-bearing ewes, were allocated to one of two groups according to their diet, either based on ad libitum naturalized pasture hay (NPH) or red clover hay (RCH), from d 45 pre-partum to d 60 post-partum. Plasma samples were collected at different times to determine albumin, cholesterol, total protein and urea, plus glucose and β-hydroxybutyrate (BHB) concentration in ewes. The data was processed using the lme4 package for R, and SPSS Statistics 23.0 for Windows. The results showed that both diet and type of pregnancy influenced the metabolic profile in ewes, showing an inverse relationship between single- and twin-bearing ewes regarding glucose and especially BHB proportions from pre-partum to birth. During post-partum, higher urea concentrations were observed in twin- and single-bearing ewes fed RCH in contrast to those fed NPH, as a result of the higher-quality forage offered to ewes. Regarding lambs, the diet and type of pregnancy influenced the total protein and urea levels, where an inverse relationship at birth and early post-partum between albumin and cholesterol vs. total protein and urea was detected, reflecting a trend (P value between 0.06 and 0.07) to a better performance by groups of single lambs, especially those from single-bearing ewes fed RCH. Finally, under the conditions of this study, the maternal diet and type of pregnancy influenced the plasma metabolic response in ewes and their lambs, affecting the lamb performance especially at birth.

Influence of Maternal Factors (Weight, Body Condition, Parity, and Pregnancy Rank) on Plasma Metabolites of Dairy Ewes and Their Lambs

Pregnancy and lactation are challenging states that affect maternal and lamb health. In Lacaune dairy sheep, we evaluated the impact of parity, pregnancy rank, and body condition on body weight and the condition of ewes and lambs in mid-pregnancy (75 ± 5 d), in late pregnancy (142 ± 4d), and postpartum (52 ± 5d pp). Maternal age was associated with initial decreases, followed by increases, in body weight and condition. After lambing, both mature and maiden ewes lost weight and body condition. Maternal indices of glucose, protein, and lipid metabolism were within physiological values during pregnancy, but postpartum values depended on maternal parity and pregnancy rank, with multiple-pregnant ewes showing a postpartum increase in glucose and maiden sheep a postpartum increase in plasma cholesterol concentration. Male lambs were heavier than female lambs at birth, and lambs born to mothers with higher body condition scores were heavier. Lambs born as singletons were heavier than those born in litters. Maternal age and pregnancy rank did not influence lamb metabolic indicators. Sex affected plasma concentrations of glucose, triglycerides, and cholesterol. Maternal metabolic indicators showed minimal effects on lamb phenotype. These results suggest that, when appropriately fed, dairy sheep can cover the metabolic demands of pregnancy and milk production, regardless of age and pregnancy rank.

The response of ruminal fermentation, epithelium-associated microbiota, and epithelial barrier function to severe feed restriction in pregnant ewes

The objective of this study was to evaluate the changes in the ruminal fermentation, epithelium-associated microbiota, and ruminal epithelial barrier function in response to severe feed restriction (SFR) in pregnant ewes. Sixteen pregnant ewes (108 d of gestation) were randomly blocked and assigned to 1 of 2 treatments: control (CON, n = 8) and SFR (n = 8). Ewes were fed a common diet with a 60:40 forage to concentrate ratio for 7-d baseline period followed by a SFR challenge period. Ewes on the SFR treatment were restricted to 30% of the base for 15 d. At the end of the experimental period, all animals were slaughtered and then ruminal contents and ruminal epithelial tissue were collected. Results showed that ruminal pH was greater in SFR group (P = 0.040) compared with CON group, while SFR decreased (P < 0.05) the concentrations of ruminal acetate, propionate, butyrate, and total volatile fatty acid. A plot of principal coordinate analysis and analysis of molecular variance revealed that the composition of ruminal epithelial bacterial communities in the CON group was distinct from that of the ruminal epithelial microbiome in the SFR animals. At the genus level, SFR increased the abundance of unclassified Neisseriaceae, Comamonas, and Papillibacter, and decreased the proportion of Howardella, Desulfobulbus, and Suttonella (P < 0.05) compared with CON group. The metagenome of ruminal epithelium-associated microbiota predicted by PICRUSt revealed that the SFR significantly affected 14 metabolic pathways, and 9 were significantly enriched in the SFR group. In particular, SFR markedly increased relative abundances of dominant gene families involved in amino acid metabolism (P = 0.003), cellular processes and signaling (P = 0.021), and lipid metabolism (P = 0.001). The real-time PCR results showed SFR decreased the mRNA expression of IL-10 (P = 0.003) and upregulated the mRNA expression of IL-6 (P = 0.003) and TLR4 (P = 0.021). The mRNA expression of Claudin-1 (P = 0.001) and ZO-1 (P = 0.009) were lower in the SFR group compared with the CON group. Generally, our data suggest that SFR decreased most ruminal fermentation parameters, altered the composition of rumen epithelium-associated microbiota, and compromised the barrier function of rumen epithelium. These findings are of great importance for understanding the alteration in the rumen function following SFR in pregnant ewes.

Hepatic Metabolic Profile Reveals the Adaptive Mechanisms of Ewes to Severe Undernutrition during Late Gestation

The mechanisms underlying the adaption of liver metabolism to the undernutrition in ewes during late gestation remain unclear. This research aimed to explore the adaptive mechanisms of liver metabolism by hepatic metabolome analysis in pregnant ewes to the negative energy balance induced by severe feed restriction. Twenty ewes carrying multiple fetuses and gestating for 115 days were fed normally or restricted to a 30% feed level (10 ewes in each group) for 15 days. All ewes were sacrificed and hepatic samples were collected and analyzed by liquid chromatography-mass spectrometry. Both the principal components analysis and partial least squares of discriminant analysis of hepatic metabolites showed the clear separation between ewes in the control and severely feed-restricted groups. The metabolic profile demonstrated that the proportions of differential metabolites between the two groups in fatty acids and lipids, organic acids, and amino acids and derivatives were 61.11%, 16.67%, and 11.11%, respectively. Enriched pathways of differential metabolites were mainly involved in fatty acids and amino acids metabolism and biosynthesis. Correlation networks of differential metabolites revealed that general metabolic pattern was changed apparently and mainly based on fatty acids and lipids in the livers of feed-restricted ewes. The accumulation and oxidation of long-chain fatty acids were intensified in the livers of feed-restricted ewes, while those of medium-chain fatty acids were the opposite. In general, severe feed restriction significantly affected the levels of hepatic metabolites and altered the overall metabolic pattern. Furthermore, fatty acids oxidation as well as the utilization of amino acids and organic acids were intensified to adapt to the negative energy balance during late gestation.

Molecular mechanisms of lipid metabolism disorder in livers of ewes with pregnancy toxemia

Pathogenesis of pregnancy toxemia (PT) is believed to be associated with the disruption of lipid metabolism. The present study aimed to explore the underlying mechanisms of lipid metabolism disorder in the livers of ewes with PT. In total, 10 pregnant ewes were fed normally (control group) whereas another 10 were subjected to 70% level feed restriction for 15 days to establish a pathological model of PT. Results showed that, as compared with the controls, the levels of blood β-hydroxybutyrate (BHBA), non-esterified fatty acids (NEFAs) and cholesterol were greater (P&lt;0.05) and blood glucose level was lower (P&lt;0.05) in PT ewes. The contents of NEFAs, BHBA, cholesterol and triglyceride were higher (P&lt;0.05) and glycerol content was lower (P&lt;0.05) in hepatic tissues of PT ewes than those of the controls. For ewes with PT, excessive fat vacuoles were observed in liver sections stained with hematoxylin-eosin; furthermore, inner structures of hepatocytes including nuclei, mitochondria and endoplasmic reticulum were damaged seriously according to the results of transmission electron microscope. Real-time PCR data showed that compared with the controls, the expression of hepatic genes involved in fatty acid oxidation (FAO) and triglyceride synthesis (TGS) was enhanced (P&lt;0.05) whereas that related to acetyl-CoA metabolism (ACM) was repressed (P&lt;0.05) in PT ewes. Generally, our results showed that negative energy balance altered the expression of genes involved in FAO, ACM and TGS, further caused lipid metabolism disorder in livers, resulting in PT of ewes. Our findings may provide the molecular basis for novel therapeutic strategies against this systemic metabolic disease in sheep.

Evaluation of a fibrate, specific stimulant of PPARα, as a therapeutic alternative to the treatment of clinical ovine pregnancy toxaemia

Ovine pregnancy toxaemia is a metabolic disorder affecting sheep in their last 6 weeks of pregnancy as a result of their inability to maintain adequate energy homoeostasis. Different alternative treatments are available with variable results. The aim of this research was to evaluate a peroxisome proliferator-activated receptor alpha (PPARα) stimulant as an alternative to treat clinical pregnancy toxaemia. Thirty-three adult sheep, with known gestation date and carrying a single foetus, were fasted from day 130 of gestation until animals showed clinical disease. From that moment onwards, sheep were treated during 6 days with three different therapeutic alternatives: 10 mg/kg of 2-methyl-2-phenoxy-propionic acid; 10 mg/kg of 2-methyl-2-phenoxy-propionic acid + 100 mL of propylene glycol oral; or 100 mL of propylene glycol oral. Glycaemia and serum β-hydroxybutyrate (BHOB) were determined daily. Liver biopsies were taken at day 130 of gestation, at the beginning and end of treatments and at 5 days postpartum, evaluating the extent and degree of the steatosis lesion. Even though in sheep treated with 2-methyl-2-phenoxy-propionic acid, serum concentrations of glucose and BHOB recovered more slowly, we conclude that 2-methyl-2-phenoxy-propionic acid alone or combined with propylene glycol can be used as an alternative to effectively treat fatty liver, and therefore pregnancy toxaemia.

Evaluation of three therapeutic alternatives for the early treatment of ovine pregnancy toxaemia

BACKGROUND

Ovine pregnancy toxaemia is a common metabolic disorder of ewes due to increased foetal energy requirements in late pregnancy. This pathology is a metabolic condition characterized by hypoglycaemia and hyperketonaemia resulting in the inability of the animal to maintain an adequate energy balance. The response to treatment is effective, if it is started in the early stages of the disease, when irreversible neurological injuries have not yet been established. The aim was to evaluate three therapeutic alternatives to effectively reverse the disease process in its early stages. For this, thirty adult Corriedale ewes, pregnant with a single lamb, were randomly separated in three groups of ten animals each, at day 130 of gestation. From that day onwards, ewes were locked up for forage fasting until glycaemia reached clinical values defining sub-clinical pregnancy toxaemia (1.59 ± 0.24 mmol/L). After fasting, ewes grazed and received a treatment for 4 days: 50 ml i.v. infusions of hypertonic glucose and 20 UI insulin/ewe/day s.c. or 100 ml/sheep/12 h of glycerol together with propylene glycol oral solution or fed with pasture supplemented with two daily intakes 300 g/sheep of cracked corn. Glycaemia and ß-hydroxybutyrate were determined in all the animals from the beginning of fasting until the completion of the treatment.

RESULTS

Fasting caused a decline in blood glucose in the 3 groups. This decline continued until fasting was withdrawn and treatment began. Thereafter blood glucose increased in all three groups, although in the group supplemented with glycerol and propylene glycol it started to increase significantly after 12 h. The values of ß-hydroxybutyrate decreased in the 3 groups at the start of treatment, and this decline was more pronounced earlier on and in the group supplemented with glycerol and propylene glycol. We found no significant differences between all experimental groups. No animal showed clinical signs of pregnancy toxaemia throughout the research.

CONCLUSIONS

The three treatments administered to sheep affected by sub-clinical pregnancy toxaemia were able to restore normal concentration of glucose and ß-hydroxybutyrate in blood, although per os administration of 100 ml/sheep/12 h of glycerol with propylene glycol, was the most successful treatment, normalizing the aforementioned biochemical parameters in a shorter time.