Pregnancy impairs ketone body disposal in late gestating ewes: Implications for onset of pregnancy toxaemia

Energy Metabolite, Immunity, Antioxidant Capacity, and Rumen Microbiota Differences Between Ewes in Late Gestation Carrying Single, Twin, and Triplet Fetuses

The objective of this study was to investigate the differences in the energy metabolites, immunity, antioxidant capacity, and rumen microbiota of ewes with different numbers of fetuses. Thirty healthy ewes were selected and divided into single- (SL, n = 10), twin- (TL, n = 10), and triplet-fetal (PL, n = 10) ewes according to the number of fetuses. Sampling was carried out on days 21 (Q21) and 7 (Q7) before lambing. The results show no differences (p > 0.05) in the DMI and BW of ewes with different numbers of fetuses, and the body condition score (BCS) of PL ewes was lower (p < 0.05) than that of SL ewes. The concentrations of β-hydroxybutyric acid (BHBA), non-esterified fatty acids (NEFA), interleukin-2 (IL-2), interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α) in the PL ewes were higher (p < 0.05), while the glucose (Glu), triglyceride (TG), total cholesterol (TC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) values were lower (p < 0.05) than those of the SL ewes. ANOSIM analysis showed that the rumen bacterial structure of the SL, TL, and PL ewes was different on days Q21 and Q7. The relative abundance of Firmicutes and Bacteroidota in the rumen was affected (p < 0.05) by the number of fetuses: the relative abundance of Firmicutes (Ruminococcus, Butyrivibrio, Christensenellaceae_R-7_group, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, and Anaeroplasma) was higher (p < 0.05), while that of Bacteroidota (Prevotella, Prevotellaceae_UCG-003, and Prevotellaceae_UCG-001) was lower (p < 0.05) in the SL ewes than in the PL ewes. In summary, the rumen microbial structure and energy metabolites of ewes in late gestation with different numbers of fetuses were different. Triplet-fetal ewes were characterized by lower BCS and antioxidant capacity and were prone to the triggering of inflammatory responses.

Relationship between rumen microbiota and pregnancy toxemia in ewes

Introduction

Pregnancy toxemia (PT) is a nutritional metabolic disease of ewes in late pregnancy. This study aimed to reveal the relationship between rumen microbiota and PT.

Methods

We selected 10 healthy ewes (CON) and 10 pregnancy toxemia ewes (PT) at 135 days of gestation according to the blood β-hydroxybutyrate (BHBA), glucose (Glu) concentrations and clinical symptoms. Blood and rumen fluid were collected before morning feeding to determine serum biochemical indices and rumen fermentation parameters. Total DNA of rumen fluid was extracted and the V3-V4 regions of 16S rRNA were amplified by PCR for high-throughput sequencing.

Results

The results showed that the serum concentrations of Glu, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), uric acid (UA), creatinine (Cr), acetate, propionate, butyrate, and microbial crude protein (MCP) were decreased (p < 0.05) and the concentrations of BHBA, aspartate aminotransferase (AST), acetate to propionate ratio (A/P), and ammonia nitrogen (NH3-N)were higher (p < 0.05) in PT ewes than those in CON ewes. 16S rRNA analysis showed the differences of β-diversity were observed in rumen microbiota between CON and PT ewes. At the phylum level, the relative abundance of Bacteroidota and Proteobacteria were higher (p < 0.01), while Firmicutes was lower (p < 0.01) in PT ewes. At the genus level, the relative Prevotella, Butyrivibrio, Ruminococcus, Lachnospiraceae_AC2044_group, Lachnospiraceae_XPB1014_group, Lachnospiraceae_ND3007_group, and Oribacterium were lower (p < 0.01) in PT ewes. Meanwhile, the relative abundance of Oribacterium, Butyrivibrio, Ruminococcus, and Lachnospiraceae_AC2044_group were positively correlated (p < 0.01) with Glu, INS, acetate, propionate, and butyrate, and negatively correlated (p < 0.01) with BHBA, P, GC, AST, and A/P.

Discussion

In conclusion, the decrease of Oribacterium, Butyrivibrio, Ruminococcus, and Lachnospiraceae_AC2044_group in the rumen of PT ewes reduced the concentrations of volatile fatty acids (acetate, propionate, and butyrate) and serum Glu, and increased BHBA concentration, indicating that the differences in rumen bacteria genera were related to pregnancy toxemia of ewes.

Conventional and Doppler ultrasonographic diagnosis of subclinical pregnancy toxemia with altered serum cortisol and biochemical parameters in pregnant does

The pathogenesis and diagnosis of subclinical pregnancy toxemia (SCPT) remain elusive and need further investigation in pregnant does. Therefore, the aim of our study was to describe the typical properties of hepatic venous hemodynamics by Doppler ultrasonography. A total of 70 pregnant does were classified based on the blood serum concentrations of β-hydroxybutyric acid (βHBA), pregnant does were categorized into control group (βHBA concentrations <0.8 mmol/L; n = 40) and SCPT group (βHBA concentrations >0.8 mmol/L; n = 30). DRAMISKI 4vet slim diagnostic ultrasound scanner with B, M, and Doppler (color, power, pulsing wave) modes was used for diagnosis of SCPT. Total serum cortisol level was quantitative using chemiluminescent immunoassay. Serum glucose, triglycerides, cholesterol, HDL and LDL- cholesterol and LDH- cholesterol were measured by colorimetric and kinetic methods. Liver ultrasonography of does with SCPT had been shown mild fatty infiltration with rounded margin, which was characterized by hyperechoic area. There was a significant decrease in the values of portal vein diameter (PVD), portal vein area (PVA), portal mean velocity (PMV) and portal blood flow (PBF) in SCPT does compared to control pregnant does. PVD, PVA and PBF were negatively correlated with βHBA concentrations in does with SCPT (P < 0.05). PVD was inversely associated with serum cholesterol and triglycerides concentrations (P < 0.05). In conclusions, Doppler ultrasonography examinations of pregnant does with SCPT indicate abnormal hepatic variation. Reduced PVD, PVA, PMV and PBF together with increased βHBA concentrations could predict SCPT in does with fair sensitivity and specificity.

Variations of blood metabolites in single- and multiple-bearing Ossimi ewes during the transition period

Evaluation of the metabolic profile indices allows early detection and treatment of various metabolic disorders during the transition period in ewes. This study aimed to determine the variations in the blood metabolites around lambing in Ossimi ewes. The blood metabolites were investigated in ewes with single (n = 27) and multiple (n = 9) lambs at 3- and 1-week pre-lambing and 3-week post-lambing. The plasma concentrations of glucose were higher in single-bearing ewes than those in multiple-bearing ewes (p < .05), moreover, its lowest value was measured at 1-week prepartum in both groups. Throughout the study period, the serum concentrations of non-esterified fatty acids (NEFA) were significantly increased in ewes with multiple lambs compared to ewes with single lambs (p < .05), and the highest value was found at 1-week before parturition in both groups. In addition, the serum level of beta-hydroxybutyric acid (BHBA) was higher at 3-week postpartum, and it was significantly increased in multiple-bearing ewes than that in single-bearing ones (p < .05) at 3-week pre-lambing. In both groups, the lowest values of total proteins were determined 1-week before lambing, and its concentrations, at 3- and 1-week prepartum, were higher in ewes with single lambs than those with multiple lambs (p < .05). In contrast, the serum concentrations of albumin were significantly lowered 1-week postpartum (p < .05), and without significant differences between both groups (p > .05). The serum activities of aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT) were significantly increased at 1-week after parturition in both groups (p < .05). Furthermore, the serum activities of AST were higher in multiple-bearing ewes than those in single-bearing ones at 3-week pre-lambing and 3-week post-lambing (p < .05). Variable positive and negative correlations were determined among the blood metabolites. In conclusion, physiological adaptations are associated with the fluctuation of the blood metabolites around lambing. The higher the number of foetuses the higher the metabolic variations in Ossimi ewes. Therefore, regular metabolic profiling for health monitoring may be necessary to avoid disease development during the transition period.

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 in Sheep and Goats

Pregnancy toxemia is a common metabolic disease of late pregnant ewes and does, which potentially has devastating impacts on health and performance. This metabolic syndrome is not only one of over conditioned animals but is more typically associated with inadequate energy intake to support pregnancy requirements leading to body protein and fat mobilization. Blood chemistries provide insight into diagnosis and possibly may predict responsiveness to treatment and outcome. Early recognition of the disease with appropriate intervention is the best approach to minimizing the impact of this disease in the sheep flock or goat herd.

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.

Effect of Sugar Beet Pulp and Anionic Salts on Metabolic Status and Mineral Homeostasis during the Peri-Parturient Period of Dairy Sheep

Sugar beet pulp is a popular by-product of sugar extraction; however, it can potentially cause depletion of Ca availability due to its oxalic content. The experiment examined the effect of sugar beet pulp and anionic salts administration during the dry period on the serum concentration of calcium, magnesium, phosphate, and potassium of dairy sheep. Eighty-seven sheep were divided into three groups (A, B, and C) according to their body condition score (BCS) and age at 40 days before the expected lambing. All groups received alfalfa hay, mixed grass straw, and a concentrate supplement. The concentrate fed to groups B and C contained sugar beet pulp. The nutritional value fed to all three groups was similar, except for Dietary Cation Anion Difference (DCAD). Animals of group A had a DCAD of +198 mEq/kg, animals of group B of +188 mEq/kg, and animals of group C were fed 20 gr/d ammonium chloride to achieve a negative DCAD (-52 mEq/kg). All groups were fed the same ration after lambing. Blood samples were collected 30 d, 20 d, 17 d, 14 d, 10 d, 7 d, and 4 d before lambing (a.p.), 6 h, 12 h, 24 h, 7 d, 10 d, and 15 d after lambing (p.p) for calcium, magnesium, phosphate, and potassium, and 30 d a.p., 7 d, and 15 d p.p. for beta hydroxybutyrate acid (BHBA) concentrations. Urine samples were also collected 20 d, 10 d, 4 d a.p., and 7 d p.p for the evaluation of pH levels. Ca levels of the control group decreased earlier and were lower at 4 d a.p. compared to those of group B and C. Additionally, the control group showed lower p values compared to group C at 20 d and 17 d a.p. P levels recovered earlier post parturition in young (age 1-1.5 years old) compared to older ewes. Group C had lower urine pH values throughout the pre-parturient period, reflecting the acidifying effect of the administered ammonium chloride, without any side effect on macromineral blood concentration. Feeding sugar beet pulp and systemic acidifying before parturition is considered safe and might even be beneficial in preventing hypocalcemia.

Changes in plasma fatty acids profile in hyperketonemic ewes during early lactation: a preliminary study

The transition from late pregnancy to early lactation is characterized by marked changes in energy balance of dairy ruminants. The mobilization of adipose tissue led to an increase in plasma non-esterified fatty acids (NEFA) and β-hydroxybutyrate (BHB). The aim of this study was to analyze the total plasma fatty acids of healthy and hyperketonemic dairy ewes in early lactation through gas chromatography (GC) to evaluate metabolic alterations. An observational study was used with a cross-sectional experimental design. Forty-six Sarda dairy ewes were enrolled in the immediate post-partum (7 ± 3 days in milk) and divided into two groups according to serum BHB concentration: non-hyperketonemic group (n = 28; BHB < 0.86 mmol/L) and hyperketonemic group (n = 18; BHB ≥ 0.86 mmol/L). A two-way ANOVA included the effect of group and parity was used to evaluate differences in fatty acids (FA) concentrations. A total of 34 plasma FA was assessed using GC. 12 out of 34 FA showed a significant different between groups and 3 out of 34 were tended to significance. Only NEFA concentration and stearic acid were influenced by parity. The results may suggest possible links with lipid metabolism, inflammatory and immune responses in hyperketonemic group. In conclusion, GC represents a useful tool in the study of hyperketonemia and primiparous dairy ewes might show a greater risk to develop this condition.

Transcriptome profiling of hepatic and renal mRNAs and lncRNAs under a nutritional restriction during pregnancy in a sheep model

This study aimed to investigate the transcriptome profiles of liver and kidney in pregnant sheep under a nutritional restriction. Twenty Hu sheep were segregated into control group (CON) and severe feed restriction (FR) group. Results showed that the concentration of insulin decreased, whereas glucagon, epinephrine, and norepinephrine increased in the FR group. Histological morphology showed no apparent difference in terms of fat deposition in the kidney. In addition, FR significantly decreased the hepatic gene expression of gluconeogenic genes. However, in the kidney, the relative mRNA expression levels of gluconeogenic genes and glucose transporter 1 were observed to increase while the mRNA expression of sodium-glucose co-transporter 1 were decreased by FR. The differentially expressed genes in the liver were associated with fatty acid metabolism and inflammation. In the kidney, FR mainly activated the gluconeogenesis improving negative energy balance. These results provide a better understanding of the consequences of starvation during pregnancy.

Milk Fatty Acids Composition Changes According to β-Hydroxybutyrate Concentrations in Ewes during Early Lactation

Simple Summary

Ketosis can occur during the last six weeks of gestation and continue to the early weeks of lactation due to an increase in energy requirement. This condition can cause substantial economic issues because of the decrease in production, the cost of medical management, the loss of the mothers and the lambs. A better knowledge of this disorder and its early diagnosis could make treatment more effective and optimize productivity. The aims of this study were to understand the metabolic status of the early-lactating ewes and to identify biomarkers for precocious diagnosis of subclinical ketosis using gas chromatographic technique. Different relationships were found between milk fatty acids and metabolic status of the ewes. Furthermore, 8 potential biomarkers were determined.

Abstract

Ketosis is a metabolic disease of pregnant and lactating ewes linked to a negative energy balance which can cause different economic losses. The aims of this study were to understand the metabolic status of the early-lactating ewes and to identify biomarkers for early diagnosis of subclinical ketosis. Forty-six Sarda ewes were selected in the immediate post-partum for the collection of the biological samples. A blood sample from the jugular vein was used to determine β-Hydroxybutyrate (BHB) concentrations. Animals were divided into two groups: BHB 0 or healthy group (n = 28) with BHB concentration < 0.86 mmol/L; and BHB 1 or subclinical ketosis (n = 18) with a BHB concentration ≥ 0.86 mmol/L. Ten mL of pool milk were collected at the morning milking for the analyses. The concentration of 34 milk fatty acids was evaluated using gas chromatography. Two biochemical parameters and 11 milk fatty acids of the total lipid fraction presented a p-value ≤ 0.05. The study revealed different relationships with tricarboxylic acid cycle, blood flows, immune and nervous systems, cell functions, inflammatory response, and oxidative stress status. Eight parameters were significant for the receiver operating characteristic (ROC) analysis with an area under the curve greater than 0.70.

Short communication: Associations between nonesterified fatty acids, β-hydroxybutyrate, and glucose in periparturient dairy goats

The objective of the present study was to use longitudinal data to examine the relationships between blood concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), and glucose during the transition period in dairy goats. Weekly blood samples were collected from Saanen goats from a commercial herd in Australia [1-7 yr; body weight 70 ± 16.0 kg; body condition score 2.5 ± 0.3; and daily milk yield 2.4 ± 0.73 L/d; all mean ± standard deviation (SD)]. The weekly prevalence of goats above hyperketonemic levels (BHB ≥0.8 mmol/L) was approximately 6 times greater postpartum than antepartum. As well, of the 935 goats sampled antepartum, 50 (5%) had at least 1 hyperketonemic event, and 823 (88%) had at least 1 event of NEFA above the threshold (≥0.3 mmol/L). Of 847 goats tested postpartum, 258 (30%) had at least 1 hyperketonemic event, and 690 goats (81%) had at least 1 event of NEFA above the threshold (≥ 0.7 mmol/L). Substantial variation was found when analyzing the mean days of maximum NEFA and maximum BHB concentrations antepartum (-11 ± 6.6 and -14 ± 7.2 d, respectively, mean ± SD) and postpartum (14 ± 6.6 and 9 ± 6.8 d, respectively, mean ± SD). We observed moderate to strong relationships between NEFA and BHB concentrations (r = 0.66) and between NEFA and glucose concentrations (r = -0.46) throughout the transition period. Our results suggested that 3 to 16 d in milk is the best sampling window for monitoring hyperketonemia in dairy goats, and that results from simultaneous BHB and glucose tests provide an improved indication of the fat mobilization and energy status of the herd when measured close to this timeframe.

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.

Glucose related endocrine and metabolic responses following bolus intravenous hypertonic dextrose administration in Iranian fat-tailed ewes at different pre and post parturition periods

Providing glucose as primary metabolic fuel for maintenance, foetal growth and milk production may be considered necessary for protection against negative energy balance and metabolic disorders. Five adult Ghezel ewes were selected 4 weeks before their parturition and followed at 2 weeks before, 2 and 4 weeks and 2, 3 and 4 months after parturition. Dextrose 50% was administered at 500 mg/kg, 10 mL/kg/hour, and blood samples were collected from all ewes prior to and 1, 2, 3 and 4 hours after 50% dextrose infusion. Serum levels of glucose, beta-hydroxybutyric acid, non-esterified fatty acids, cholesterol, triglyceride, high, low and very low density lipoproteins, insulin, triiodothyronine, thyroxine, prolactin, cortisol and insulin like growth factor-1 were evaluated. Glucose and insulin were increased significantly and immediately following intravenous dextrose administration at all studied periods. The levels of beta-hydroxybutyric acid and non-esterified fatty acids were significantly decreased following dextrose infusion at all periods. Triiodothyronine was decreased in pregnant ewes and increased in non-pregnant, lactating ones. The significant increasing cortisol patterns were detected at 2 and 4 weeks before and 2 and 4 weeks after parturition following dextrose administrations. The decreasing patterns of insulin like growth factor-1 were seen in all studied periods. Prolactin was significantly increased following dextrose administration at 4 and 2 weeks before and 2 weeks after parturition. Bolus intravenous hypertonic dextrose administration could induce the obvious endocrine and metabolic responses in Ghezel ewes via providing a source of energy and the glucose is an important direct controller of metabolic interactions in Ghezel ewes.

Biochemical, endocrine, and histopathological profile of liver and kidneys of sheep with pregnancy toxemia

ABSTRACT: The objective of the present study was to characterize the biochemical, hormonal, and mineral profile, and histopathology of the liver and kidneys, related to the severity of natural cases of pregnancy toxemia (PT) in sheep. A total of 45 sheep with PT were analyzed at the “Clínica de Bovinos”, Campus Garanhuns-UFRPE. The animals were submitted to clinical examination, followed by the collection of blood and urine. A necropsy was performed on thirteen animals that died and a histopathological examination was performed on samples of liver and kidneys. Increased creatinine, urea, glucose, fructosamine, non-esterified fatty acids, β-hydroxybutyrate, cortisol, chlorine, amylase, aspartate aminotransferase, gamma-glutamyltransferase, and folic acid were found, whereas insulin, potassium, and total and ionizable calcium presented low values for the species. Total protein, albumin, globulin, sodium, magnesium, and vitamin B12 remained within the normal range. In the macroscopic analysis of the liver, it was possible to observe an increase in organ and border size, yellowish coloration and parenchyma that varied from firm to friable. Vacuolation of the hepatocytes and renal tubular cells was observed. Metabolic disorders in sheep associated with hepatic and renal lesions are more apparent in overweight animals. With the greater impairment in hepatic and renal function, the clinical prognosis of animals with a high body score should be considered reserved.

Maternal Metabolic Demands Caused by Pregnancy and Lactation: Association with Productivity and Offspring Phenotype in High-Yielding Dairy Ewes

Simple Summary

This study assessed the effects of metabolic load imposed by pregnancy and lactation on productivity and offspring performance in high-yielding dairy sheep. Productivity was assessed in terms of offspring and maternal milk yield, metabolic profile, and body condition. Our results show that maternal productivity and lamb body weight and growth are not compromised by pregnancy and lactation because dairy sheep, when appropriately managed, seem to be able to cover metabolic demands of pregnancy and high milk production without losing productivity.

Abstract

Pregnancy and lactation, especially when concurrent, create a rather metabolically demanding situation in dairy ruminants, but little is known about their effects on offspring phenotype and milk yield. Here, we evaluated the impact of pregnancy and lactation on the metabolic traits and productive performance of Lacaune dairy sheep and their offspring. Productive performance was measured in terms of milk yield, body weight (BW), body condition score (BCS), and size. Productivity was assessed during mid-pregnancy (75 ± 5 d) and late pregnancy (142 ± 4 d) and at 52 ± 5 d in the postpartum period. During pregnancy, high-yielding ewes had higher BW, BCS, plasma glucose, cholesterol, β-OHB, and NEFA than low-yielding ewes, but lower levels of lactate and urea. High-yielding animals had lower BCS after lambing, but their lambs showed greater growth. Productivity during lactation was affected by ewe age and parity: Mature ewes (but not maiden sheep) whose BCS increased steeply during pregnancy yielded more milk in the subsequent lactation than those whose BCS did not increase. Lamb BW and size were positively associated with milk yield in the subsequent lactation. Mature ewes had higher yields than maiden sheep, and mature ewes with multiple pregnancies produced more milk than those with singleton pregnancies. Ewes with male singleton pregnancies also showed higher yield than those with female singletons. These results demonstrate that high-yielding dairy sheep, when appropriately fed and managed, can adequately cover the metabolic demands of pregnancy and high milk production (even when concurrent) without losing productivity.

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.

Effects of feed intake restriction during late pregnancy on the function, anti-oxidation capability and acute phase protein synthesis of ovine liver

Objective

An experiment was conducted to investigate the effects of feed intake restriction during late pregnancy on the function, anti-oxidation capability and acute phase protein synthesis of ovine liver.

Methods

Eighteen time-mated ewes with singleton fetuses were allocated to three groups: restricted group 1 (RG1, 0.18 MJ ME/kg W^0.75 d, n = 6), restricted group 2 (RG2, 0.33 MJ ME/kg W^0.75 d), n = 6) and a control group (CG, ad libitum, 0.67 MJ ME/kg W^0.75 d, n = 6). The feed restriction period was from 90 days to 140 days of pregnancy.

Results

The ewe’s body weight, liver weights, water, and protein content of liver in the restricted groups were reduced compared with the CG group (p<0.05), but the liver fat contents in the RG1 group were higher than those of the CG group (p<0.05). The increased hepatic collagen fibers and reticular fibers were observed in the restricted groups with the reduction of energy intake. The concentrations of nonesterified free fatty acids in the RG1 and RG2 groups were higher than those of the CG group with the reduction of energy intake (p<0.05), but there were decreased concentrations of lipoprotein lipase and hepatic lipase in both restricted groups compared with the CG group (p<0.05). In addition, the increased concentrations of β-hydroxybutyric acid, triglycerides, malondialdehyde, total antioxidant capacity and activities of superoxide dismutase activity and catalase were found in the RG1 group, and the concentrations of cholinesterase in the RG1 group were reduced compared with the CG group (p<0.05). For the concentrations of acute phase proteins, the C-reactive protein (CRP) in the RG1 group were reduced compared with the CG group, but there were no differences in haptoglobin relative to the controls (p>0.05).

Conclusion

The fat accumulation, increased hepatic fibrosis, antioxidant imbalance and modified synthesis of acute phase proteins were induced in ewe’s liver by maternal malnutrition during late pregnancy, which were detrimental for liver function to accommodate pregnancy.

Evaluation of the Nova Vet Meter for sheep-side monitoring of β-hydroxybutyric acid (BHBA) and description of ewe BHBA during late gestation in three flocks from the Northeastern U.S

Prevention of metabolic diseases in small ruminants may improve production efficiency and profitability, yet ewes carrying multiples or who are in poor body condition are at increased susceptibility to develop ketosis. This study evaluated the hand-held Nova Vet Meter to accurately detect β-hydroxybutyric acid (BHBA) concentrations in ewes and determined the percentage of ewes at moderate (0.8 to 1.5 mmol/L BHBA) and greatest (≥1.6 mmol/L BHBA) risk to develop ketosis during late gestation. To validate the Nova Vet Meter, BHBA concentrations of 104 paired blood samples were measured using the Nova Vet Meter and gold-standard laboratory analysis. Receiver operating characteristics were calculated. The accuracy and sensitivity of detecting BHBA concentrations at 0.8 to 1.5 mmol/L were 94.2% and 97.3%, respectively. The accuracy and sensitivity of detecting BHBA concentrations ≥ 1.6 mmol/L were 98.0% and 50.0%, respectively. Ewe body weight (BW), body condition score (BCS), and BHBA of 117 ewes from three flocks were determined weekly during the four weeks before parturition. During the last three weeks of gestation >20% of ewes were identified with moderate risk to develop ketosis. During the last four weeks of gestation, ewes carrying triplets had reduced BCS (P = 0.0002) and increased BHBA concentrations (P < 0.0001) compared with singleton and twin pregnancies. Ewe BHBA did not correlate with lamb birth weight (R² = 0.003; P = 0.41). In conclusion, the Nova Vet Meter is suitable for sheep-side BHBA monitoring between 0.8 and 1.5 mmol/L, but further testing is necessary to evaluate BHBA readings ≥1.6 mmol/L.

The association of serum β-hydroxybutyrate concentration with fetal number and health indicators in late-gestation ewes in commercial meat flocks in Prince Edward Island

Late-gestation ewes are susceptible to ketonemia resulting from high energy requirement for fetal growth during the last few weeks of pregnancy. High lamb mortality is a possible consequence of effects of ketonemia on both ewes and lambs. Determining risk factors to ketonemia is a fundamental step to identify ewes at risk, in order to avoid losses caused by ketonemia. Serum β-hydroxybutyrate (BHBA) concentrations of 384 late-gestation ewe samples were determined. Physical examinations, including body condition, FAMACHA^© and hygiene scoring, were performed. Udders and teeth were also examined. Fecal floatation was performed to detect gastrointestinal helminth eggs of the ewe fecal samples. General feeding management practices and season at sampling were recorded. Litter sizes were retrieved from lambing records. Factors associated with log serum BHBA concentration were determined using a linear mixed model, with flock and lambing groups as random effects. The mean serum BHBA concentration was 545.8 (±453.3) μmol/l. Ewes with a body condition score (BCS) of 2.5-3.5 had significantly lower log BHBA concentrations than ewes with a BCS of ≤2.0, by 19.7% (p = 0.035). Ewes with a BCS of >3.5 had a trend toward higher log BHBA concentrations compared to ewes with a BCS of 2.5-3.5. Ewes with a FAMACHA^© score of 3 had significantly higher log BHBA concentrations than ewes with a FAMACHA^© score of 1 or 2, by 12.1% (p = 0.049). Ewes in which gastrointestinal helminth eggs were detected had significantly higher log BHBA concentrations than ewes in which helminth eggs were not detected, by 12.3% (p = 0.040). An increased litter size was associated with higher log BHBA concentration (p ≤ 0.003), with the log BHBA concentrations of ewes having twins, triplets, and quadruplets or quintuplets were higher than those of ewes having singleton by 19.2%, 30.4%, and 85.2%, respectively. Season at sampling confounded the association between log BHBA concentration and FAMACHA^© score, and therefore was retained in the final model even though it was not statistically significant. Intra-class correlation coefficients at the flock and lambing group levels were 0.14 and 0.32, respectively.

Earwax metabolomics: An innovative pilot metabolic profiling study for assessing metabolic changes in ewes during periparturition period

Important metabolic changes occur during transition period of late pregnancy and early lactation to meet increasing energy demands of the growing fetus and for milk production. The aim of this investigation is to present an innovative and non-invasive tool using ewe earwax sample analysis to assess the metabolic profile in ewes during late pregnancy and early lactation. In this work, earwax samples were collected from 28 healthy Brazilian Santa Inês ewes divided into 3 sub-groups: 9 non-pregnant ewes, 6 pregnant ewes in the last 30 days of gestation, and 13 lactating ewes ≤ 30 days postpartum. Then, a range of metabolites including volatile organic compounds (VOC), amino acids (AA), and minerals were profiled and quantified in the samples by applying headspace gas chromatography/mass spectrometry, high performance liquid chromatography/tandem mass spectrometry, and inductively coupled plasma-optical emission spectrometry, respectively. As evident in our results, significant changes were observed in the metabolite profile of earwax between the studied groups where a remarkable elevation was detected in the levels of non-esterified fatty acids, alcohols, ketones, and hydroxy urea in the VOC profile of samples obtained from pregnant and lactating ewes. Meanwhile, a significant decrease was detected in the levels of 9 minerals and 14 AA including essential AA (leucine, phenyl alanine, lysine, isoleucine, threonine, valine), conditionally essential AA (arginine, glycine, tyrosine, proline, serine), and a non-essential AA (alanine). Multivariate analysis using robust principal component analysis and hierarchical cluster analysis was successfully applied to discriminate the three study groups using the variations of metabolites in the two stress states (pregnancy and lactation) from the healthy non-stress condition. The innovative developed method was successful in evaluating pre- and post-parturient metabolic changes using earwax and can in the future be applied to recognize markers for diagnosis, prevention, and intervention of pregnancy complications in ewes.

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.

Invited review: Cessation of lactation: Effects on animal welfare

The forced cessation of milk production, or dry-off, is a routine management practice in dairy cattle, sheep, and goats. This practice initiates a dry period, during which the animal is not milked. Milking begins again after parturition. Most of the literature on the dry period has focused on how various drying-off strategies affect milk production and disease; little work to date has addressed how dry-off affects the overall welfare of the dairy animal. The first aim of this review was to present an overview of the importance of dry-off and how it is commonly achieved. Our review shows that much scientific progress has been made in improving health status between lactations. The second aim was to identify important gaps in the literature, of which 2 key research disparities have been identified. We find that much of the work to date has focused on cattle and very little research has examined dry-off in dairy sheep and goats. We also find a lack of research addressing how common dry-off methodologies affect animal welfare on more than just a biological level, regardless of species.

Definition of prepartum hyperketonemia in dairy goats

A prospective cohort study was conducted on 1,081 dairy goats from 10 commercial herds in Québec (Canada) to define prepartum hyperketonemia based on optimal blood β-hydroxybutyrate acid threshold values for the early prediction of pregnancy toxemia (PT) and mortality in late-gestation dairy goats. All pregnant goats had blood sampled weekly during the last 5wk of pregnancy. The blood was analyzed directly on the farm for β-hydroxybutyrate acid quantification using a Precision Xtra meter (Abbott Diabetes Care, Saint-Laurent, QC, Canada). Body condition scores on the lumbar region and sternum were noted. Each goat was classified as being at low (n=973) or high risk (n=108) of having PT by producers based on a standardized definition. The optimal threshold for predicting a PT diagnosis or mortality for each week before kidding was determined based on the highest sum of sensitivity and specificity. The association between hyperketonemia and subsequent PT was tested using a multivariable logistic regression model considering hyperketonemia at wk 4 prepartum, litter size, and body condition score at wk 4 prepartum as covariates, and herd and parturition cohort as random effects. The association between mortality and hyperketonemia was also tested using a logistic regression model accounting for the presence or absence of treatment during the last month of pregnancy. The hyperketonemia definition based on PT varied between ≥0.4 and ≥0.9mmol/L during the last 5wk prepartum. Goats affected by hyperketonemia at wk 4 prepartum and with a large litter size (≥3 fetuses) had 2.1 and 40.5 times the odds, respectively, of subsequent PT than other goats. Hyperketonemia definitions based on mortality varied between ≥0.6 and ≥1.4mmol/L during the last 4wk prepartum, and was ≥1.7mmol/L during the first week postpartum. Goats affected by hyperketonemia and treated by producers had 3.4 and 11.8 times the odds, respectively, of subsequent mortality than did other goats. These results showed that prepartum hyperketonemia could be defined in dairy goats using subsequent risks of PT or mortality during the last month of pregnancy.

Prepartum administration of recombinant bovine somatotropin (rBST) on adaptation to subclinical ketosis of the ewes and performance of the lambs

The aim of this study was to determine the effect of prepartum rbST injection on the metabolic profile of pregnant ewes induced to subclinical ketosis, as well as the metabolism until seven days of life and weight gain until seven weeks of life of the lambs. Twenty seven pregnant ewes of the pantaneiro genetic group were used, divided into two groups: rbST group (n = 14) and control group (n = 13). The rbST group received two applications of 1 mg/kg of rbST, at 97 and 111 days gestation, while the control group received placebo injections. There were significant differences between groups in levels of GGT in the ketosis post induction period and BHB concentrations in the postpartum period. Concentrations of glucose, urea, phosphorus, albumin, cholesterol, AST, NEFA and insulin were not different between dams from the two groups in different periods of the study (P>0.05). There was an effect of rbST on body weight observed already at fourteen days of life (P<0.0001), there was an increase in serum phosphorus levels at birth of lambs (P=0.0014), and albumin at seven days of life (P = 0.0014) of the lambs, with no difference between groups for the other metabolites. Therefore, the use of rbST was effective in increasing the weight of the lambs until the seventh week of life. In addition, rbST treatment had positive effects on the dam metabolism with reduction of liver overload, as indicated by decreased GGT after ketosis induction and decreased BHB at the postpartum period.

Achados bioquímicos, eletrolíticos e hormonais de cabras acometidas com toxemia da prenhez

A abrangência dos estudos sobre a toxemia da prenhez (TP) tem sido constante e inovadora em alguns conceitos, porém o estudo dos casos clínicos naturais em cabras é inexistente no Brasil. Diante disso, realizou-se análise das alterações clínicas, do perfil bioquímico, eletrolítico e hormonal com o objetivo de compreender a fisiopatogenia da enfermidade. Foram avaliadas 22 cabras atendidas na Clínica de Bovinos, Campus Garanhuns/UFRPE, diagnosticadas com TP, no período de 2007 a 2012. Realizou-se exame clínico e coleta de sangue e urina, para análise do perfil bioquímico e hormonal. Acentuadas alterações clínicas foram observadas, como decúbito, apatia, dispneia, aumento da temperatura corpórea, mucosas congestas, vasos episclerais injetados, desidratação, anorexia, hipomotilidade ou atonia ruminal, edema nos membros. Os resultados laboratoriais revelaram valores elevados para ureia, creatinina, ácidos graxos não esterificados (AGNE), β-hidroxibutirato, amilase e cortisol, enquanto as variáveis: proteína total, albumina, cálcio total, cálcio ionizado, fósforo, a relação cálcio e fósforo, sódio e insulina encontraram-se diminuídos. Outros parâmetros bioquímicos e eletrolíticos, como frutosamina, globulina, cloro, potássio e magnésio mantiveram-se dentro da faixa de normalidade. Quanto a glicemia, foram constatados três condições nas cabras com TP, normoglicêmicas (50%), hiperglicêmicas (27,28%) e hipoglicêmicas (22,72%). Dos 17 (77,27%) animais que obtiveram alta 10 (58,82%) eram normoglicêmicos. Vieram a óbito 22,8 % (5/22), no qual 60% (3/5) delas estavam hiperglicêmicas. A média de nascimento por cabra foi superior a duas crias. Verificou-se existir associação fortemente positiva dos AGNE's com a albumina (r=0,60), fraca com o β-hidroxibutirato (r=0,10) e glicose (r=0,03). Porém, existiu relação fortemente negativa dos AGNE's com a insulina (r= -0,70), moderada com o cortisol (r= -0,52) e amilase (r= -0,30). Marcadas alterações clínicas e metabólicas são observadas em cabras com TP, em que o aumento de certos metabólitos do perfil energético e hormonal se torna importante ferramenta para o diagnóstico e constitui um bom instrumento para avaliar a magnitude da condição clínica dos animais enfermos. Os dados encontrados servem de referência para estudos sobre nutrição e metabolismo em cabras com TP.

Post-glucose load changes of plasma key metabolite and insulin concentrations during pregnancy and lactation in ewes with different susceptibility to pregnancy toxaemia

Insulin resistance during late gestation may act as a predisposing factor of ovine pregnancy toxaemia (OPT). To evaluate the insulin action on energy metabolism in ewes with different susceptibilities to OPT, intravenous glucose tolerance tests (1 mmol glucose/kg body weight) were performed in 5.6 ± 0.7 year old, slightly underfed German Blackheaded Mutton ewes [high-risk (HR) ewes] and 2.5 year old, overnourished Finnish Landrace ewes [low-risk (LR) ewes] during mid and late pregnancy, during early lactation and during the dry period. Plasma samples were analysed for glucose, insulin, non-esterified fatty acids (NEFA) and β-hydroxybutyrate (β-HB). The glucose elimination rate and the glucose-stimulated first-phase insulin secretion were significantly (p < 0.05) lower in the HR, in relation to the LR group combining the data of all gestational stages. The basal rate of lipolysis was significantly increased in the HR ewes during late pregnancy, but the NEFA clearance after the glucose load was similar in both groups during all reproductive stages. Plasma β-HB concentrations decreased only in the LR ewes after the glucose load during late pregnancy. Results indicate an insulin resistance in the HR ewes regarding the glucose utilization and the ketone body formation during late pregnancy. The insulin resistance in the HR ewes may represent one predisposing factor responsible for the susceptibility to OPT. Further scientific work is necessary to elucidate whether this insulin resistance was due to breed, age or nutritional state.

Motivation to obtain a food reward of pregnant ewes in negative energy balance: behavioural, metabolic and endocrine considerations

Low food availability often coincides with pregnancy in grazing animals. This study investigated how chronic reductions in food intake affected feeding motivation, and metabolic and endocrine parameters in pregnant sheep, which might be indicative of compromised welfare. Ewes with an initial Body Condition Score of 2.7±0.3 (BCS; 0 indicates emaciation and 5 obesity) were fed to attain low (LBC 2.0±0.0,), medium (MBC 2.9±0.1) or high BCS (HBC 3.7±0.1) in the first trimester of pregnancy. A feeding motivation test in which sheep were required to walk a set distance for a palatable food reward was conducted in the second trimester. LBC and MBC ewes consumed more rewards (P=0.001) and displayed a higher expenditure (P=0.02) than HBC ewes, LBC ewes also tended to consume more rewards than MBC ewes (P=0.09). Plasma leptin and glucose concentrations were inversely correlated to expenditure (both P<0.05) and appear to be associated with hunger in sheep. LBC ewes were in negative energy balance, with lower muscle dimensions, plasma glucose, leptin, insulin, cortisol, and insulin-like growth factor-1 concentrations and higher free fatty acids concentrations compared to HBC ewes; metabolic and endocrine parameters of the MBC ewes were intermediate. The high feeding motivation and negative energy balance of low BCS ewes suggested an increased risk of compromised welfare. Imposing even a small cost on a food reward reduced motivation substantially in high BCS ewes (despite high intake when food was freely available). Assessment of a willingness to work for rewards, combined with measures of key metabolic and endocrine parameters, may provide sensitive barometers of welfare in energetically-taxed animals.

Evolutionary interactions between diabetes and development

Because of the complications of diabetes affecting the mothers and their fetus/newborns are less known, this review examined the epidemiologic and mechanistic issues involved in the developmental programming of diabetic mothers. This overview showed that sperm, egg, zygote or blastocyst derived from diabetic parents may develop into offspring with high risk of any type of diabetes, even if placed in a normal uterus, producing developmental delay, embryopathy, geno- and cyto-toxicity, teratogenic changes, free radicals and apoptosis. These early insults may then lead to an increased rate of miscarriage and congenital anomalies depending on free radicals signaling and cell-death pathways involved by the diabetogenic agents. Furthermore, sperm, egg, zygote or blastocyst from normal parents will have an increased risk of diabetes if placed in a diabetic uterus. Interestingly, diabetes has deleterious effect on male/female reproductive functions and on the development of the blastocysts/embryos. Indeed, this review hypothesized that the long-term effects of diabetes during the pregnancy (gestational diabetes) may influence, generally, on the health of the embryos, newborns (perinatal life) and adulthood. However, there are obvious species differences between pregnant women and animal models. Thus, maintaining normoglycaemia during pregnancy may play an important role in a healthy life for the newborns.

Chronic fetal and maternal instrumentation in pregnant sheep: effect on gestation length and birthweight

The objective was to compare gestation length in chronically instrumented (laboratory) pregnant sheep (n = 131) and in the breeding flock (n = 476) that provided the experimental sheep. In the breeding flock, gestation length was normally distributed and varied between 141 and 151 days (mean = 147 +/- 0.1 days). In the laboratory sheep, gestation length varied between 128 and 151 days (mean = 142 +/- 1 day), and was bimodal, with 35.9% delivering preterm (<141 days). To examine potential factors that contributed to the preterm birth, a severity score was used, which comprised surgery characteristics, number of experiments and maternal or fetal complications. There was a significant inverse linear relationship (P < 0.001) between the total severity score and gestation length. The median values for the surgical (15 v. 12), overall complication (6 v. 2), maternal complication (2 v. 0) and fetal complication (2 v. 2) components were significantly greater in the preterm compared with the term groups. There was no relationship between fetal number and gestation length in either group. It is concluded that in chronic pregnant sheep preparations, there is a significant incidence of preterm birth and that this is associated with the severity of the surgical intervention and with several maternal and fetal complications.

Glucose homeostasis during canine pregnancy: Insulin resistance, ketosis, and hypoglycemia

Through a variety of mechanisms, pregnancy causes insulin resistance, which suppresses the intracellular transport of glucose and increases blood glucose concentrations. In the extreme, gestational diabetes (GDM) mellitus may develop. In addition to insulin resistance, pregnant bitches have decreased ability to produce glucose via gluconeogenesis, glycogenolysis and lipolysis, because the normal multi-factorial responses to hypoglycemia are blunted late in pregnancy. Simply fasting late-pregnant bitches is sufficient to cause blood glucose and insulin concentrations to decrease and ketones to increase. The purpose of this paper is to review the clinical implications of pregnancy-associated changes in glucose homeostasis in bitches.