Unilateral twin pregnancy: A non-infectious factor required for the etiological diagnosis of abortion in dairy herds.

Twin pregnancies are classified into bilateral (one fetus in each uterine horn: 44%) and unilateral (both fetuses in the same uterine horn, right or left: 56%). The incidence of abortion during mid- to late gestation is approximately 1% in cows carrying bilateral twins and more than 40% in cows carrying unilateral twins. In this period, abortion seems most commonly associated with infectious agents. However, although this imbalanced abortion rate may imply that unilateral twin pregnancy is a non-infectious abortion factor, few available data can describe the cause of abortions in twin pregnancies. The current findings suggest that unilateral twin pregnancy is a non-infectious factor required for the etiological diagnosis of abortion in dairy herds.

Study on reproductive performance of Holstein x Lai Sind crossbred dairy heifers and cows at smallholdings in Ho Chi Minh City, Vietnam.

The reproductive performance of Holstein x Lai Sind crossbred dairy heifers and cows was evaluated at smallholdings in Ho Chi Minh City (HCMC). The data of 232 heifers and 244 cows (261 lactations) from 35 small dairy farms was collected over a 2-year period, from 2013 to 2014. The overall mean for age at first service (AFS), days between first and last service (DFLS), and age at conception (AC) of heifers was 479 (±80), 38 (±80), and 517 (±114) days, respectively. Average number of services per conception (NSC), conception rate (CR), and conception rate at first service (CRFS) was 1.8 (±1.4), 55, and 58%, respectively. The overall mean for the waiting period (WP), DFLS, and days open (DO) of cows was 109 (±52), 133 (±114), and 242 (±129) days, respectively. The mean for NSC, CR, and CRFS was 4.3 (±2.7), 23, and 14%, respectively. A very significant decrease in AFS and AC according to the year of birth, and a significant increase in AFS according to body weight at first insemination (>320 kg) were observed. The CRFS of heifers inseminated in 2013 was significantly higher than in 2014. Monthly mean CR in heifers and cows was negatively correlated with THI. The WP, DFLS, DO, and NSC of cows significantly decreased according to the year of calving. Cows that calved in rainy season had a significantly longer WP than in dry season. The occurrence of postpartum (PP) diseases was accompanied by an increase in WP, DO, and NSC. A decrease in body condition score (BCS) between calving and 60th day (C60) and also between 60th and 120th day of lactation resulted in a significant increase in WP and DO. A decrease in BCS between C60 was also accompanied by a considerable reduction in CRFS of cows. Season and BCS at insemination had a significant effect on NSC and CR of cows. Reproductive performance was satisfactory for heifers, but poor for cows. Losses of BCS during the first months of lactation and at insemination were the major risk factors for this poor performance. Moreover, the season had a more negative effect on fertility in cows than in heifers.

An echographic study of follicular growth during induced estrus in female Azawak zebu in Niger.

An echographic study of follicular growth up to ovulation was carried out on 42 lactating Azawak cows (Bos indicus) after estrus induction by means of a PGF2α or a procedure involving the administration of progesterone vaginally (PRID® DELTA: progesterone-releasing intravaginal device) for a 10-day period and the injection of a PGF2α and an ECG (400 and 800 IU) on withdrawal. All the animals were inseminated 12 and 24 h after the onset of estrus. The percentage of estrus induced was not significantly different between the two groups of animals (81 %). The average time delay before the onset of estrus was significantly longer after injection of a PGF2α (84.8 ± 26.0 h) than after withdrawal of the PRID® (59.2 ± 5.8 h). The average duration of the estrus was significantly shorter after its induction by PGF2α (12.6 ± 2.6 h) than after induction by progesterone (22.9 ± 2.7 h). There was not a significant difference in the interval between the beginning of estrus and ovulation in animals treated by PGF2α (30.3 h) and progesterone (28.4 h). Injection of a PGF2α was accompanied by a significantly lower rate of gestation than that obtained after treatment of animals by progesterone (31.2 vs 54.5 %). These results confirm the necessity to adapt an insemination policy to hormonal treatment for estrus induction in B. indicus.

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N'Dama cattle.

The aim of this study was to assess the dose (300 to 600 IU) effects of equine chorionic gonadotropin (eCG) on the preovulatory follicle diameter, growth rate and time of ovulation characterized by echography. The eCG was injected at the end (D0) of the 7-day treatment with a controlled internal device release (CIDR®) and a PGF2α being injected 2 days before the removal of the CIDR® (d-2). The 120 N'Dama female were distributed into five experimental groups. The control group (n = 26) was treated with physiological saline at the removal of the CIDR®, while the animals in the four treated groups received, respectively, 300 IU (n = 25), 400 IU (n = 24), 500 IU (n = 22) and 600 IU (n = 23) of eCG. The diameter of the preovulatory follicle was significantly higher (P < 0.05) in the animals treated with 300 IU (10.1 ± 1.4 mm) than in untreated animals (9.3 ± 1.2 mm). Follicle growth rate was significantly (P < 0.05) higher in treated animals (1.0 ± 0.4 mm/day) than in the control group (0.9 ± 0.4 mm/day). The average interval between the time of eCG injection and ovulation was similar in the non-treated (83.7 ± 14.4 h) and treated animals (79.7 ± 11.9). Treated animals showed a significant increase in the percentage of ovulation (94.7 % compared to 73.1 %) (P < 0.01). Use of eCG contributed towards synchronising the time of ovulation between 72 to 96 h, which would facilitate the use of systematic insemination.

Propaedeutic and Therapeutic Practices Used for Retained Fetal Membranes by Rural European Veterinary Practitioners.

The present study aimed to monitor the practices of European veterinarians for the diagnosis and treatment of retained fetal membranes in cattle. A questionnaire was established and distributed to veterinarians from five European countries. A total of 700 veterinarians participated in the survey. A vaginal examination, general examination and uterine palpation are carried out by 71%, 38% and 23% of veterinarians, respectively. Moreover, half of the veterinarians attempt to remove the placenta manually, 70% of them administer a combined local and general treatment if the cow has a fever (more than 39.5 °C), and 50% of them only administer IU treatment if no fever is observed. Tetracyclins, cefapirin and penicillins are the most used intrauterine (IU) antibiotics, whereas penicillin is the most used parenteral one. All other European veterinarians were less likely to use cefapirin and more likely to use oxytocin, Ca perfusion and NSAID than French and Walloon veterinarians. In conclusion, our study confirms the necessity of improving and rationalizing the diagnostic and therapeutic approach of the RFM, mainly to reduce the important problem of antibiotic resistance.

Structural equation models to estimate risk of infection and tolerance to bovine mastitis.

BACKGROUND: One method to improve durably animal welfare is to select, as reproducers, animals with the highest ability to resist or tolerate infection. To do so, it is necessary to distinguish direct and indirect mechanisms of resistance and tolerance because selection on these traits is believed to have different epidemiological and evolutionary consequences. METHODS: We propose structural equation models with latent variables (1) to quantify the latent risk of infection and to identify, among the many potential mediators of infection, the few ones that influence it significantly and (2) to estimate direct and indirect levels of tolerance of animals infected naturally with pathogens. We applied the method to two surveys of bovine mastitis in the Walloon region of Belgium, in which we recorded herd management practices, mastitis frequency, and results of bacteriological analyses of milk samples. RESULTS AND DISCUSSION: Structural equation models suggested that, among more than 35 surveyed herd characteristics, only nine (age, addition of urea in the rations, treatment of subclinical mastitis, presence of dirty liner, cows with hyperkeratotic teats, machine stripping, pre- and post-milking teat disinfection, and housing of milking cows in cubicles) were directly and significantly related to a latent measure of bovine mastitis, and that treatment of subclinical mastitis was involved in the pathway between post-milking teat disinfection and latent mastitis. These models also allowed the separation of direct and indirect effects of bacterial infection on milk productivity. Results suggested that infected cows were tolerant but not resistant to mastitis pathogens. CONCLUSIONS: We revealed the advantages of structural equation models, compared to classical models, for dissecting measurements of resistance and tolerance to infectious diseases, here bovine mastitis. Using our method, we identified nine major risk factors that were directly associated with an increased risk of mastitis and suggested that cows were tolerant but not resistant to mastitis. Selection should aim at improved resistance to infection by mastitis pathogens, although further investigations are needed due to the limitations of the data used in this study.

Genital abnormalities associated to lack of uterine adenogenesis or endometrial gland dysgenesis of female dromedary camels (Camelus dromedarius).

Background: The developmental disruption of the müllerian duct and the endometrial dynamic can generate genital lesions that could contribute to infertility. Aim: This paper discusses two cases of genital conditions associated to endometrial gland pathologies in nulliparous female camels. Methods: Macroscopic examinations and histopathological description were performed on congenital and acquired genital abnormalities with endometrial gland anomalies. Results: The first case is endometrial gland agenesis associated to unilateral uterine aplasia, and the second case is endometrial gland dysgenesis associated to metritis. The prevalence of each case is estimated to be 0.6%. The most specific microscopic features associated to the endometrial gland agenesis were the presence of endometrial stromal proliferation and homogenous hyalinization of the myometrium. The acute metritis was associated to endometrial-activated stroma with focal infiltration with inflammatory cells on the endometrium and myometrium and the spontaneous endometrial gland dysgenesis. Conclusion: This study reveals the importance of congenital abnormalities during the routine reproductive examination of peripubertal animals, as well as the association of histopathological complementary examination for the research functional and inflammatory anomalies of the uterus. Genetic screening of breeders would be very important in the search for genetic risk factors associated with these congenital pathologies, which can be disseminated by reproductive biotechnologies.

Linking first lactation survival to milk yield and components and lactation persistency in Tunisian Holstein cows.

Genetic parameters were estimated for first lactation survival defined as a binary trait (alive or dead to second calving) and the curve shape traits of milk yield, fat and protein percentages using information from 25 981 primiparous Tunisian Holsteins. For each trait, shape curves (i.e. peak lactation, persistency), level of production adjusted to 305 days in milk (DIMs) for total milk yield (TMY), and average fat (TF %) and protein (TP %) percentages were defined. Variance components were estimated with a linear random regression model under three bivariate animal models. Production traits were modelled by fixed herd  × â€¯test-day (TD) interaction effects, fixed classes of 25 DIMs  × â€¯age of calving  × â€¯season of calving interaction effects, fixed classes of pregnancy, random environment effects and random additive genetic effects. Survival was modelled by fixed herd  × â€¯year of calving interaction effects and age of calving  × â€¯season of calving interaction effects, random permanent environment effects, and random additive genetic effects. Heritability ( h 2 ) estimates were 0.03 ( ± 0.01 ) for survival and 0.23 ( ± 0.01 ), 0.31 ( ± 0.01 ) and 0.31 ( ± 0.01 ) for TMY, TF % and TP %, respectively. Genetic correlations between survival and TMY, TF % and TP % were 0.26 ( ± 0.08 ), - 0.24  ( ± 0.06 ) and - 0.13  ( ± 0.06 ), respectively. Genetic correlations between survival and persistency for fat and protein percentages were  - 0.35  ( ± 0.09 ) and  - 0.19  ( ± 0.09 ), respectively. Cows that had higher persistencies for fat and protein percentages were more likely not to survive.

Relationship between haptoglobin, serum amyloid A, and clinical status in a survey of dairy herds during a 6-month period.

BACKGROUND: Haptoglobin and serum amyloid A are major acute phase proteins in cattle. Dairy cattle often develop pathologic conditions in the peripartum period; acute phase proteins may be useful in their diagnosis. OBJECTIVES: The purpose of this study was to compare the accuracy of serum haptoglobin (Hp) and serum amyloid A (SAA) concentrations with clinical health status for diagnosing disease during the peripartum period in dairy cattle. METHODS: Dairy cows from 4 herds were evaluated every 15 days over a 6-month period. Health status was determined by thorough clinical examination. Haptoglobin and SAA concentrations were measured in serum using validated methods and the results were classified as positive or negative based on defined cutoff points. Disease prevalence, sensitivity, and specificity were compared using clinical examination as the gold standard. RESULTS: A total of 1896 samples from 158 cows were analyzed. Significant increases in mean Hp and SAA concentrations were observed in the week following parturition in both primiparous and multiparous cows, although high interindividual variability was observed. Both Hp and SAA had low sensitivity but higher specificity in determining disease status compared with clinical examination. Increased concentrations of Hp and SAA were found in <10% of samples from clinically healthy cows, except in the week after parturition. CONCLUSIONS: Haptoglobin and serum amyloid A should be used with caution as markers of inflammation in the week after calving. Poor sensitivity in other postpartum periods could be related to the higher incidence of chronic (vs acute) inflammation. Haptoglobin may be appropriate for routine screening, but further work needs to be done to assess its value as an indicator of herd health.