Periparturient Disorders Research Articles

​Assessment of the Levels of Biomarkers of Oxidative Stress during Peri-parturient Period in Gir Cows

Background: Dairy cows during late pregnancy, parturition or early lactation may be subjected to oxidative stress or the production of reactive oxygen metabolites. An imbalance between increased production of ROS and reduced availability of antioxidant defenses near the time of parturition increases oxidative stress and may contribute to peri-parturient disorders in dairy cows therefore in present investigation, of biomarkers of oxidative stress during peri-parturient period in Gir cows were studied. Methods: Total 42 peri-parturient Gir cows were included in the present study. Ten apparently healthy Gir cows were also selected (which were outside the peri-parturient period) to have base line data on levels of biomarkers of oxidative stress for the comparison and analysis. The study was conducted in southern part of Rajasthan. Result: The mean values of malondialdehyde (n mol/g Hb), super oxidase dismutase (U/mg Hb), reduced glutathione (mM) and catalase (µmol of H2O2 consumed /min/mg Hb) during pre-partum period and post-partum period in Gir cows was 227.34±9.48 and 255.85±11.15; 72.97±4.96 and 56.13±4.30; 2.72±0.15 and 2.27±0.15 and 139.85±3.81 and 121.57±4.65, respectively. Determination of levels of biomarkers of oxidative stress revealed that level of malondialdehyde (MDA) was significantly (P less than 0.05) increased during peri-parturient period in Gir cows whereas, levels of superoxide dismutase (SOD) and reduced Glutathione (GSH) were significantly (P less than 0.05) decreased. The level of catalase was also significantly (P less than 0.01) decreased during peri-parturient period in Gir cows.

Evident similarity of porcine postparturient dysgalactia to subclinical porcine coliform mastitis

The present commentary aims to motivate future research and initiate new investigation on porcine periparturient disorders. After a short characterization of the clinical presentation of coliform mastitis, this commentary concentrates on the subclinical variant. The subclinical form of the disease resembles in most aspects what is referred to as postparturient dysgalactia syndrome of sows, and is considered highly prevalent in the field. Since the recent introduction of the ill-defined postparturient dysgalactia syndrome, experimental work has declined. Except for review articles, there is a shortage of recent publications in this area. Previously published experimental data led to a promising approach to prevent coliform mastitis by reducing the level of teat contamination by coliform bacteria. With the ongoing need to reduce antimicrobial use in food-producing animals, there is a continued need to investigate preventive strategies.

Managing the transition period of dairy cows to prevent major metabolic postpartum disorders

The transition period refers to the time between 3-4 weeks prior to and 4 weeks after calving. This is the period with the highest incidence of metabolic and other periparturient disorders. Many of these disorders interrelated and often coincide. Proper management and nutrition of the transition cow are critical for obtaining maximum dry matter intake, good health, increased reproductive efficiency and optimum milk production in the following lactation. The present review is comprised from two parts. In the first one, selected information is provided concerning the most important metabolic diseases of the transition period (hypocalcemia, ketosis) and, in brief, how hypocalcemia is interrelated to other diseases (mastitis, metritis, retained fetal membranes and abomasal displacement). In the second part, up-to-date nutritional methods applied in the transition period to prevent these metabolic periparturient diseases, with emphasis in hypocalcemia, are described.

Epidemiology of intramammary infections with Staphylococcus aureus and mastitis streptococci in a dairy cattle herd with a history of recurrent clinical mastitis.

The aim of the present work was to examine a dairy herd with an anamnesis of recurrent clinical mastitis and decreased milk production. A total of 239 individual cow milk samples originating from asymptomatic cows were collected at four-month intervals and examined mainly for the presence of Staphylococcus aureus and mastitis streptococci using standard cultivation methods. In total, 29.7% and 9.2% samples were positive for S. aureus and mastitis streptococci, respectively. Unlike for mastitis streptococci, the prevalence of animals positive for S. aureus had an increasing trend (p<0.05; Chi-squared test for trend) with rising parity. Despite in vitro susceptibility of S. aureus to potentiated penicillins and cephalosporins, the persistence of S. aureus was observed in cows undergoing intramammary treatment with amoxicillin/clavulanic acid (a potentiated penicillin antibiotic). All isolates of S. aureus were biofilm-positive and had the same macrorestriction pattern. Furthermore, no dependence was observed between the occurrence of S. aureus in milk and previous cases of clinical mastitis, reproductive and periparturient disorders and administration of antibiotics. In contrast to S. aureus, the occurrence of mastitis streptococci in milk was linked with previous cases of clinical mastitis and intramammary administration of antibiotics.

Investigation of the effect of pegbovigrastim on some periparturient immune disorders and performance in Mexican dairy herds

This study analyzed the efficacy of pegbovigrastim (Imrestor, Elanco Animal Health, Greenfield, IN) on some health and production parameters in lactating dairy cows. Primiparous and multiparous Holsteins from 17 Mexican dairy herds (n = 10,238) were included in this study, which was conducted in 2015. Treated cows (n = 5,025) received Imrestor approximately 7 d before expected calving and again within 24 h after calving; control cows (n = 5,213) did not receive a placebo. Clinical mastitis (MAS; 0 to 30 DIM), retained placenta (RP), and clinical metritis (MET; 0 to 21 DIM) occurrences were recorded, as well as the number of medication days, medical treatments needed, and the number of days that milk was discarded due to medication administered for disease. Milk yield was measured from calving until 120 d in milk. Imrestor reduced the incidence of MAS by 25%, and the odds ratio of having mastitis in the first 30 d in milk was 35% greater for control cows than for Imrestor cows. Imrestor treatment reduced the number of medical treatments required for MAS by 6%, and less milk was discarded due to medication for MAS as a result of the Imrestor treatment. The incidence of RP was reduced by 4.15% with Imrestor and the odds of cows having RP were 4.6% greater for control than Imrestor treatments, but they did not differ. The MET incidence was increased by 17.1% with Imrestor. The use of Imrestor around parturition increased by 5.8% the odds of inseminating cows during the first 100 d after calving. Imrestor-treated multiparous cows with MAS produced 2.1 kg/d more milk than control cows with MAS during the first 30 d of their lactation. Imrestor-treated multiparous cows with MET produced 2.3 kg/d more milk than MET control cows during the first 120 d of their lactation. We conclude that Imrestor can help the dairy cow cope with immune periparturient disorders and can increase the milk yield of dairy cows due to a healthier transition, despite a reported increase in the incidence of MET.

Ultrasonographic examination of pregnant ewes: From early diagnosis of pregnancy to early prediction of dystocia

Ultrasonographic examination has been established as the most valuable method for early and accurate pregnancy diagnosis in ewes. Early and accurate diagnosis of pregnancy is particularly useful for correct health management of flocks during gestation. It is also important to study pregnancy processes and foetal development with a non-invasive method, as ultrasonographic examination, because various events might affect normal development of foetus and viability of offspring. Evaluation of normal physiological pregnancy progress and outcome, as well as pregnancy disorders and peri-parturient disorders are significant in sheep health management. Hence, ability to perform pregnancy diagnosis and to identify common pathological conditions of pregnant ewes is of importance to clinicians active in sheep practice. Further, monitoring of foetal growth during pregnancy is useful for those working with sheep. Moreover, various disorders of pregnant ewes (e.g., pregnancy toxaemia) can lead to dystocia and it would be beneficial to predict such cases, if any of these disorders has been diagnosed. In all the above circumstances, ultrasonographic examination can support the veterinarian in reaching a diagnosis and in taking decisions for management of each situation.

Factors influencing the rates of pregnancy, calving and peri-parturient disorders in heifers at selected char areas of Bangladesh

The study was conducted to evaluate the factors affecting the rates of pregnancy, calving and peri-parturient disorders in heifers in selected char areas (low lying flood and erosion-prone areas in or adjacent to major rivers) of Lalmonirhat district of Bangladesh. A total of 101 artificial inseminated (AI) heifers were randomly selected for monitoring rates of pregnancy, calving and peri-parturient disorders with respect to breed of semen, source of semen, breed, age, body weight and body condition score (BCS) of heifers. The overall rates of pregnancy, calving and peri-parturient disorder were 51.5%, 45.5% and 32.6%, respectively. The differences were not significant with respect to the factors evaluated (P&gt;0.05).Bangl. vet. 2015. Vol. 32, No. 2, 65-72

Identification of predictive biomarkers of disease state in transition dairy cows

In dairy cows, periparturient disease states, such as metritis, mastitis, and laminitis, are leading to increasingly significant economic losses for the dairy industry. Treatments for these pathologies are often expensive, ineffective, or not cost-efficient, leading to production losses, high veterinary bills, or early culling of the cows. Early diagnosis or detection of these conditions before they manifest themselves could lower their incidence, level of morbidity, and the associated economic losses. In an effort to identify predictive biomarkers for postpartum or periparturient disease states in dairy cows, we undertook a cross-sectional and longitudinal metabolomics study to look at plasma metabolite levels of dairy cows during the transition period, before and after becoming ill with postpartum diseases. Specifically we employed a targeted quantitative metabolomics approach that uses direct flow injection mass spectrometry to track the metabolite changes in 120 different plasma metabolites. Blood plasma samples were collected from 12 dairy cows at 4 time points during the transition period (−4 and −1wk before and 1 and 4wk after parturition). Out of the 12 cows studied, 6 developed multiple periparturient disorders in the postcalving period, whereas the other 6 remained healthy during the entire experimental period. Multivariate data analysis (principal component analysis and partial least squares discriminant analysis) revealed a clear separation between healthy controls and diseased cows at all 4 time points. This analysis allowed us to identify several metabolites most responsible for separating the 2 groups, especially before parturition and the start of any postpartum disease. Three metabolites, carnitine, propionyl carnitine, and lysophosphatidylcholine acyl C14:0, were significantly elevated in diseased cows as compared with healthy controls as early as 4wk before parturition, whereas 2 metabolites, phosphatidylcholine acyl-alkyl C42:4 and phosphatidylcholine diacyl C42:6, could be used to discriminate healthy controls from diseased cows 1wk before parturition. A 3-metabolite plasma biomarker profile was developed that could predict which cows would develop periparturient diseases, up to 4wk before clinical symptoms appearing, with a sensitivity of 87% and a specificity of 85%. This is the first report showing that periparturient diseases can be predicted in dairy cattle before their development using a multimetabolite biomarker model. Further research is warranted to validate these potential predictive biomarkers.

Influence of vitamin E, macro and micro minerals on reproductive performance of cattle and buffalo-A review

Most of the periparturient disorders in dairy cattle and buffaloes have been associated with vitamin and mineral deficiencies. Thus supplementation during periparturient period wherein there is heavy demand and drain of nutrients could probably prevent these disorders. Further these problems need to be addressed in light of the region specific requirements.

Effect of the periparturient period on blood free amino acid concentration in dairy cows/healthy cows

A negative energy balance (NEB) attributed to sugar and lipid metabolic disorders are common in periparturient cows. The relationship between periparturient disorders and amino acid metabolism is unclear. The present study was aimed to observe the kinetics of blood free amino acids healthy periparturient cows simultaneously with the concentrations of biochemical constituents in plasma. The changes in the concentrations of plasma biochemical constituents and blood free amino acids were monitored in healthy periparturient cows. There were three types of amino acid; a group of amino acids (Val, Leu, Ile, Trp, Thr, Arg, Lys, Tyr, Ala, Pro, Asn, Orn) whose blood concentrations decreased because their consumption is accelerated under periparturient energy-shortage state, a group of AAs (Gly, Ser) whose concentrations increased because they are mobilized to compensate for periparturient energy shortage, and a group of amino acids (Glu, Gln) that are taken into the mammary gland tissues and mobilized from the start of lactation after delivery. The blood free amino acid concentrations in periparturient cows indicated the various kinetics of amino acid concentration corresponding to changes in energy generation. Analysis of amino acid metabolism should be entertained in the pathogenesis of NEB-related periparturient disorders. Key words: Cow, serum free amino acid concentration, periparturient, metabolism of amino acid.

Prevalence of Clinical Endometritis and its Impact on Reproductive Performance in Grazing Dairy Cattle in Argentina

The objective of this study was to evaluate the prevalence of clinical endometritis and its impact on reproductive performance in grazing dairy cattle in Argentina to compare data with previous reports from herds kept in confinement housing systems. A total of 243 Holstein dairy cows from three commercial dairy farms in Buenos Aires Province (Argentina) were examined for the signs of clinical endometritis 18-38 days postpartum (dpp) by external inspection and manual vaginal examination. Vaginal discharge was scored into the categories VDS 0 (transparent, clear mucus), VDS 1 (mucupurulent discharge), VDS 2 (purulent discharge) and VDS 3 (purulent discharge with fetid odour). Cows diagnosed with VDS 1 to VDS 3 were regarded as affected with clinical endometritis and cows with VDS 0 as free of clinical endometritis. All cows were re-examined 14 days later following the same examination protocol. Prevalence of clinical endometritis 18-38 dpp was 35% and decreased to 18% at re-examination. Cows with no palpable ovarian structures or periparturient disorders were at higher risk for clinical endometritis. Hazard for pregnancy was significantly lower in cows with purulent or fetid odour discharge compared with reference cows with no discharge (HR=0.49; p=0.01), resulting in a lower proportion of cows pregnant by 360 dpp (66% vs 78%). Furthermore, the number of services per pregnancy was higher for cows with clinical endometritis than for cows without clinical endometritis (4.4 vs 3.1; p=0.04). Cows with clinical endometritis were 1.6 times as likely to be culled as cows with no signs of clinical endometritis. In conclusion, the prevalence and the impact of clinical endometritis in a pasture-based, extensive dairy production system in Argentina were similar to previously published data from dairy farms with confinement production systems.

Relationship between serum nonesterified fatty acids at calving and the incidence of periparturient diseases in Holstein dairy cows

The objective was to describe the relationship between concentration of serum nonesterified fatty acids (NEFAs) at calving and the incidence of periparturient disorders in Chilean Holstein dairy cows ( Bos taurus). The study was conducted at two dairies (central Chile) with 700 milking cows each and similar management. Between July 2006 and March 2007, 350 cows were selected, and concentrations of serum NEFAs were determined at calving. The incidence of milk fever (MF), retained fetal membranes (RFMs), metritis, and clinical mastitis from calving to 100 d in lactation were consistently recorded. The relationship between concentration of serum NEFAs at calving and the incidence of periparturient diseases was determined using logistic regression. The main explanatory variable was concentration of serum NEFAs at calving. The incidence of MF, RFM, metritis, and mastitis was 5.4%, 15.6%, 10.8%, and 14.4%, respectively. There was no association between concentration of NEFAs at calving and the incidence of these conditions when the median value of NEFAs (0.9 mEq/L) was used as a cutoff. However, when the 75th percentile (1.2 mEq/L) was used as the cutoff, cows with values <1.2 mEq/L were 0.45 and 0.32 times as likely to develop clinical mastitis and MF, respectively, compared with cows with values ≥1.2 mEq/L. When the 90th percentile (1.6 mEq/L) was used as a cutoff, cows with values <1.6 mEq/L were 0.25 times as likely to develop clinical mastitis compared with cows with values ≥1.6 mEq/L. As a continuous variable, for every 0.1 mEq/L increment in NEFAs at calving, cows were 1.11 times more likely to experience clinical mastitis. In conclusion, cows with NEFA concentrations ≥1.2 mEq/L had a higher incidence of clinical mastitis and MF than that of cows with values <1.2 mEq/L.

Association Between Body Condition Score Change During the Dry Period and the Incidence of Calving-Related Disorders, and Milk Production in Holstein Cows

Body condition score (BCS) is a practical tool used to monitor energy nutrition of dairy cattle. Body condition score at calving has been associated with lactational performance; however, little information is available about cows calving with low, optimum or high BCS that either maintain, gain or lose BCS during the dry period. Therefore, the objective of the present study was to determine the association of BCS of cows that calved with low, optimum or high BCS that either gained or lost BCS during the dry period and the incidence of periparturient disorders, and milk production in Holstein cattle.

Advancing parity is associated with high milk production at the cost of body condition and increased periparturient disorders in dairy herds

The objectives of this study were to determine the effects of parity on milk production, body condition change, periparturient health, and culling in Korean dairy herds. The data utilized included; milk yield, body condition score, cow parity, calving condition, periparturient disorders, culling, and reproductive status, which were recorded from 1290 calvings in eight dairy herds. The mean milk yield in cows over 305 days increased with increasing parity (p < 0.01). Cows with parities of 3, 4, and 5 or higher lost more body condition than those with a parity of 1 during month 1 of lactation (p < 0.01), and body condition recovery by cows with parities of 4 and 5 or higher was slower (p < 0.01) than recovery by cows with parities of 1, 2, or 3 until month 3 of lactation. The risk of retained placenta, metabolic disorder, and endometritis also increased with advancing parity (p < 0.05). Moreover, the incidence of ovarian cysts was lower in cows with a parity of one than in cows with greater parities (p < 0.01). Culling rate due to reproductive failure also increased with advancing parity (p < 0.01). These results suggest that parity increases milk yield, body condition loss during early lactation, the risk of periparturient disorders, and culling due to reproductive failure in dairy herds.

Carnitine Palmitoyltransferase I in Liver of Periparturient Dairy Cows: Effects of Prepartum Intake, Postpartum Induction of Ketosis, and Periparturient Disorders

Thirty-five multiparous Holstein cows were used to determine the role of mitochondrial carnitine palmitoyltransferase I (CPT I) in liver on peripartal adaptations of fatty acid metabolism. From dry-off to parturition, cows were fed a diet at either ad libitum (n=17) or restricted intake (RI, 80% of calculated requirements for net energy; n=18). After parturition, all cows were fed a lactation diet. At 4 d in milk (DIM), cows underwent a physical examination and were classified as healthy (n=15) or having at least one periparturient disorder (PD; n=17). Cows in the healthy group were assigned to either a control (n=6) group or a ketosis induction (KI; n=9) group. Cows with periparturient disorders were assigned to a third (PDC; n=17) group. Cows in control and PDC groups were fed for ad libitum intake. Cows in KI were fed at 50% of their respective intake at d 4 postpartum starting from 5 DIM and continuing to signs of clinical ketosis or until 14 DIM; cows then were returned to ad libitum intake. Liver was biopsied at −30 d, 1 d, at signs of clinical ketosis or 14 d, and 28 d relative to parturition. Mitochondria were isolated by differential centrifugation. Activity of CPT I was 5.4 and 7.6nmol of palmitoylcarnitine formed per min/mg of protein for ad libitum and RI, respectively, at −30 DIM. Sensitivity of CPT I to its inhibitor, malonyl CoA, did not differ between ad libitum and RI cows. Differences in CPT I activity between ad libitum and RI were no longer significant at 1 DIM. Postpartum CPT I activity and malonyl CoA sensitivity at 1 DIM, onset of clinical ketosis or 14 DIM, and 28 DIM were not affected by prepartum intake (ad libitum vs. RI), postpartum health status (healthy vs. PD), or ketosis induction status (control vs. KI vs. PDC). Activity of CPT I was positively correlated with liver total lipid, liver triglyceride, liver triglyceride to glycogen ratio, and serum nonesterified fatty acids. Activity of CPT I and dry matter intake were not correlated. Prepartum intake affected prepartum CPT I activity but not malonyl CoA sensitivity. Neither induction of primary ketosis nor periparturient disorders greatly affected CPT I activity or sensitivity, which indicates that alterations of CPT I may not be a major factor in the etiology of primary ketosis or other periparturient disorders.

Prepartum Intake, Postpartum Induction of Ketosis, and Periparturient Disorders Affect the Metabolic Status of Dairy Cows

Nutritional management during the dry period may affect susceptibility of cows to metabolic and infectious diseases during the periparturient period. Thirty-five multiparous Holstein cows were used to determine the effect of prepartum intake, postpartum induction of ketosis, and periparturient disorders on metabolic status. Cows were fed a diet from dry-off to parturition at either ad libitum intake or restricted intake [RI; 80% of calculated net energy for lactation (NEL) requirement]. After parturition, all cows were fed a lactation diet. At 4 d in milk (DIM), cows underwent a physical examination and were classified as healthy or having at least one periparturient disorder (PD). Healthy cows were assigned to the control (n = 6) group or the ketosis induction (KI; n = 9) group. Cows with PD were assigned to the PD control (PDC; n = 17) group. Cows in the control and PDC groups were fed for ad libitum intake. Cows in the KI group were fed at 50% of their intake on 4 DIM from 5 to 14 DIM or until signs of clinical ketosis were observed; then, cows were returned to ad libitum intake. During the dry period, ad libitum cows ate more than RI cows; the difference in intake resulted in ad libitum cows that were in positive energy balance (142% of NEL requirement) and RI cows that were in negative energy balance (85% of NEL requirement). Prepartum intake resulted in changes in serum metabolites consistent with plane of nutrition and energy balance. Prepartum intake had no effect on postpartum intake, serum metabolites, or milk yield, but total lipid content of liver at 1 d postpartum was greater for ad libitum cows than for RI cows. The PD cows had lower intake and milk yield during the first 4 DIM than did healthy cows. During the ketosis induction period, KI cows had lower intake, milk yield, and serum glucose concentration but higher concentrations of nonesterified fatty acids and β-hydroxybutyrate in serum as well as total lipid and triacylglycerol in liver than did control cows. Cows with PD had only modest alterations in metabolic variables in blood and liver compared with healthy cows. The negative effects of PD and KI on metabolic status and milk yield were negligible by 42 DIM, although cows with PD had lower body condition score and BW. Prepartum intake did not affect postpartum metabolic status or milk yield. Periparturient disorders and induction of ketosis negatively affected metabolic status and milk yield during the first 14 DIM.

Strategies for the control of milk fever

IN the past 25 years, average milk yields in the UK national herd have increased by 30 per cent and it is expected that they will continue to rise. The...

The Effects of Feeding Fish Oil on Uterine Secretion of PGF2α, Milk Composition, and Metabolic Status of Periparturient Holstein Cows

The objectives were to determine the effect of dietary fish oil (FO) on uterine secretion of PGF2alpha, milk production, milk composition, and metabolic status during the periparturient period. Holstein cows were assigned randomly to diets containing FO (n = 13) or olive oil (OO, n = 13). Cows were fed prepartum and postpartum diets that provided approximately 200 g/d from 21 d before the expected parturition until 21 d after parturition. The FO used contained 36% eicosapentaenoic acid (EPA, C20:5, n-3) and 28% docosahexaenoic acid (DHA, C22:6, n-3). Blood samples were obtained from 14 d before the due date until d 21 postpartum. A total of 6 FO and 8 OO cows without periparturient disorders were used in the statistical analyses of PGF2alpha-metabolite (PGFM) and metabolite concentrations. Length of prepartum feeding with OO or FO did not differ. Proportions of individual and total n-3 fatty acids were increased in caruncular tissue and milk of cows fed FO. The combined concentrations of EPA and DHA in caruncular tissue were correlated positively with the number of days supplemented with FO. Cows fed FO had reduced concentrations of plasma PGFM during the 60 h immediately after parturition compared with cows fed OO. Concentrations of prostaglandin H synthase-2 mRNA and protein in caruncular tissue were unaffected by diet. Production of milk and FCM were similar between cows fed the two oil diets. However, cows fed FO produced less milk fat. Feeding FO reduced plasma concentrations of glucose. Dietary fatty acids given during the periparturient period can reduce the uterine secretion of PGF2alpha in lactating dairy cows and alter the fatty acid profile of milk fat.

Effect of intrauterine antibiotic treatment on reproductive performance of dairy cows following periparturient disease

AIMS: To quantify the effect of treating lactating dairy cows that had histories of periparturient disorders or disease with a single intrauterine infusion of 0.5 g cephapirin, 3–6 weeks prior to the start of the seasonal breeding period. METHODS: Cows (n=690) from spring-calving dairy herds (n=22) were enrolled in a prospective case-control study if they had a history of dystocia, a dead calf at calving or within 24 h of calving, retained foetal membranes (RFM), metabolic disease, twins or a vulval discharge >13 days postpartum. Cows were blocked by age, periparturient condition and calving date, and randomly assigned to be either treated with 0.5 g of cephapirin by intrauterine infusion, or left as untreated controls. Treatment occurred 24–42 days before the planned start of mating (PSM) within each herd. In addition, the reproductive tracts of 91 cows from 4 herds were examined using a vaginal speculum and rectal palpation and cervical-os discharge was scored on a scale from 0 (nil) to 3 (purulent). RESULTS: Overall, more treated cows were retained in the trial herds until pregnancy testing than control cows (p<0.05). Average 28-day submission rate was higher (93.1% vs 87.1%; p<0.05) and PSM-to-first-service interval was shorter (9 ± 1 vs 11 ± 1 days; p<0.05) in treated than control cows. The percentage of cows not pregnant at the end of the mating period was not affected by treatment overall. However, amongst cows diagnosed with RFM, a dead calf, or vulval discharge, pregnancy rates 28 and 56 days after PSM were higher for treated than control cows (p<0.05). Cows with a purulent cervical-os discharge had lower 28-day submission rates (p<0.01), lower 28-day pregnancy rates (p<0.05) and higher non-pregnant rates at the end of mating than cows with nil or mucoid cervical-os discharges. CONCLUSIONS: Intrauterine treatment with 0.5 g cephapirin improved reproductive performance of dairy cattle, especially those that had a history of RFM, a calf dead at calving or within 24 h of calving, or a vulval discharge.

Effect of Calcium and Energy Status During the Postpartum Period on Reproductive Performance in Dairy Cows

Pregnancy rate, a function of heat detection and conception rate, determines the number of days postpartum at which cows become pregnant from the voluntary waiting period.67 Cows expressing one or more estruses during the first 30 days postpartum had improved pregnancy rates compared with anestrous cows.83 This observation indicates that the physiological and hormonal events associated with estrus help restore uterine and ovarian function to a state conducive to pregnancy. A number of studies have demonstrated the relationship between hypocalcemia and parturient disorders such as dystocia, retained fetal membranes (RFM), and ketosis.13,30,68 These disorders predispose the cow to metritis, which can affect the energy status of the cow. This influences ovarian activity and resumption of cyclicity during the postpartum period.&#x0D; The energy status of the lactating dairy cow has differential effects on early follicular development and competence, ovulation and subsequent corpus luteum (CL) function during the postpartum period. As our understanding of the endocrinology and reproductive physiology of the postpartum cow has advanced, it is clear that reproductive and nutritional management systems need to be integrated to achieve optimal reproductive efficiency.&#x0D; Objectives of this presentation are 1) to describe the association between calcium status and periparturient disorders 2) to relate the differences in ovarian activity to energy status in postpartum dairy cows 3) to examine the effects of protein and fat on reproductive function during the postpartum period, and 4) to document the beneficial effects of bovine somatotropin (bST) on first-service pregnancy rates when integrated into a reproductive management program for timed insemination.