Prevalence of early postpartum health disorders in Holstein cows and associations with production, reproduction, and survival outcomes on Alberta dairy farms.

The objective of this study was to determine the prevalence and associations of early postpartum health disorders with production, reproduction, and survivability in dairy cows in Alberta. Holstein cattle (N = 1096) from 11 commercial dairy farms in Alberta, Canada were enrolled. Cows were evaluated daily for clinical postpartum health disorders and a blood sample was collected once within 2 wk after calving to diagnose subclinical disorders. Overall, 61% of cows were diagnosed with at least 1 postpartum health disorder, with 25% of cows having multiple disorders. Of the cows with only 1 health disorder, 71% were classified as inflammatory and 29% as metabolic disorders. Cows with multiple disorders were at the greatest risk of reduced milk production, impaired fertility, and leaving the herd. Cows with an inflammatory disorder had reduced productive and reproductive performance, whereas cows with a metabolic disorder were at the greatest risk of mortality.

Prévalence des troubles de santé post-partum précoces chez les vaches Holstein et associations avec les résultats de production, de reproduction et de survie dans les fermes laitières de l'Alberta. L'objectif de la présente étude était de déterminer la prévalence et les associations des troubles de santé post-partum précoces avec la production, la reproduction et la capacité de survie chez les vaches laitières en Alberta. Des bovins Holstein (N = 1096) de 11 fermes laitières commerciales en Alberta, au Canada, ont été recrutés. Les vaches ont été évaluées quotidiennement pour des problèmes cliniques de santé post-partum et un échantillon de sang a été prélevé une fois dans les 2 semaines après le vêlage pour diagnostiquer les problèmes subcliniques. Dans l'ensemble, 61 % des vaches ont reçu un diagnostic d'au moins un problème de santé post-partum, 25 % des vaches ayant des problèmes multiples. Parmi les vaches présentant un seul problème de santé, 71 % ont été classées comme inflammatoires et 29 % comme des problèmes métaboliques. Les vaches souffrant de problèmes multiples couraient le plus grand risque de réduction de la production de lait, d'impact sur la fertilité et d'élimination du troupeau. Les vaches présentant un problème inflammatoire avaient des performances de production et de reproduction réduites, tandis que les vaches présentant un problème métabolique étaient les plus exposées au risque de mortalité.(Traduit par Dr Serge Messier).

Dynamics of pre- and post-insemination progesterone profiles and insemination outcomes determined by an in-line milk analysis system in primiparous and multiparous Canadian Holstein cows.

The objective was to evaluate in-line milk progesterone (mP4) data to determine dynamics of pre- and post-insemination mP4 profiles and their associations with parity and outcomes of artificial insemination (AI) in Holstein cows. Milk progesterone (ng/mL) was quantified at pre-determined time points before and after AI through an automated in-line milk analysis system (Herd Navigator™, DeLaval International, Tumba, Sweden). Only AI (∼d0; n = 605) preceded by an mP4-decline (at least two samples of mP4 ≥5 ng/mL followed by at least one sample <5 ng/mL; d-2) were evaluated. Maximum mP4 attained between d-15 and d-2 (PrePeak), d-2, d5, d10, d14, maximum mP4 attained within 21d post-AI (PostPeak), and rate-of-daily-change between mP4 time points (ng/mL/d) were analyzed. Primiparous and multiparous cows were classified by AI outcomes based on post-AI mP4 profiles into three groups: (1) non-pregnant (OPEN; mP4-decline ≤ 30d post-AI), (2) presumed-pregnant (PREG; no mP4-decline until 55d post-AI), and (3) presumed-pregnancy loss (P-LOSS; mP4-decline between 31 and 55d post-AI). For profile comparisons, smoothed mP4 data were analyzed using mixed linear models. Primiparous cows had greater (P < 0.01) mP4 than multiparous cows at d5 (4.6 ± 0.2 vs. 2.8 ± 0.1), 10 (11.1 ± 0.4 vs. 7.6 ± 0.2), 14 (19.7 ± 0.4 vs. 16.1 ± 0.3) and PostPeak (23.5 ± 0.3 vs. 21.7 ± 0.2). The rate-of-daily-change was greater (P < 0.01) in primiparous than in multiparous cows from d-2 to 5 (+0.2 ± 0.03 vs. -0.1 ± 0.02) and from d5 to 10 (+1.2 ± 0.05 vs. +0.9 ± 0.03), but lesser (P < 0.01) from d14 to PostPeak (+0.9 ± 0.09 vs. +1.3 ± 0.06). In primiparous cows, mP4 in PREG was greater at d10 and PostPeak than OPEN (11.1 ± 0.5 and 24.2 ± 0.5 vs. 9.6 ± 0.4 and 22.3 ± 0.4, respectively, P < 0.04), but lesser at d5 than P-LOSS (4.4 ± 0.3 vs. 5.7 ± 0.4, P = 0.04). In multiparous cows, mP4 at d-2 was lesser in PREG than OPEN and P-LOSS (3.2 ± 0.1 vs. 3.4 ± 0.04 and 3.5 ± 0.1, respectively, P ≤ 0.03), but greater at d10, d14 and PostPeak in PREG than in OPEN (8.2 ± 0.4, 16.8 ± 0.5 and 22.7 ± 0.4 vs. 6.9 ± 0.3, 14.8 ± 0.3 and 19.7 ± 0.2, respectively, P < 0.01). Multiparous PREG cows had greater rate-of-daily-change in mP4 than OPEN cows from d5 to 10 and from d10 to 14 (+1.0 ± 0.06 and +2.2 ± 0.11 vs. +0.8 ± 0.04 and +1.9 ± 0.08, respectively, P < 0.03). Overall post-AI mP4 increased faster and were greater in primiparous than in multiparous cows. Based on in-line mP4 profiles, greater mP4 levels near time of AI (d-2 in multiparous and d5 in primiparous cows) and lesser mP4 beyond d10 were negatively associated with a successful pregnancy.

Relationships among early postpartum luteal activity, parity, and insemination outcomes based on in-line milk progesterone profiles in Canadian Holstein cows.

The objectives of this retrospective study were to use in-line milk progesterone (mP4) data to investigate relationships of (1) commencement of luteal activity (CLA), and (2) luteal phase (LP) length and frequency preceding first postpartum AI, with parity and AI outcomes in Canadian Holstein cows. Starting 21 ± 1 days postpartum (DPP), levels of mP4 were assessed every 2.2 ± 2.0 d through an automated in-line milk analysis system (Herd Navigator™, DeLaval International, Tumba, Sweden) until ∼55 d after first or second AI in 748 Holstein cows from two herds. The CLA was defined as the DPP of the first of at least two consecutive samples with mP4 ≥5 ng/mL, and the period with elevated mP4 (≥5 ng/mL) was defined as the LP. Cows were categorized by CLA [earlier (≤) or later (>) than 28, 35, 42, 49, 56, and 63 DPP], and by the pattern of LP frequency preceding first AI as having or not: (1) one or more normal LP (LP length ≥7 and ≤19 d); (2) one or more abnormal LP (LP length <7 or >19 d, or interluteal period ≥12 d); and (3) two or more LP (either normal or abnormal). Outcomes of first or second AI were determined by the interval between AI and cessation of the ensuing LP as: non-pregnant (mP4-decline ≤30 d), presumed-pregnant (no mP4-decline until 55 d), or presumed-pregnancy loss (mP4-decline between 31 and ≤55 d). The odds of pregnancy per AI (P/AI) at 55 d and pregnancy loss were evaluated using generalized linear mixed models. Primiparous cows had lower odds of having CLA ≤28 DPP [Odds ratio (OR) = 0.58, P = 0.002] and one or more abnormal LP (OR = 0.73, P = 0.04) than multiparous cows. In multiparous cows, CLA ≤28 DPP decreased pregnancy loss (OR = 0.48, P = 0.05) and CLA ≤56 DPP increased P/AI (OR = 4.69, P < 0.01) compared to a later CLA. Primiparous and multiparous cows that had one or more normal LP before first AI had increased P/AI (OR = 3.85 and 3.45, respectively, P < 0.01) and reduced pregnancy loss (OR = 0.26 and 0.27, respectively, P < 0.01) than cows without a normal LP. Primiparous cows that had one or more abnormal LP had decreased P/AI (OR = 0.62, P = 0.04) and increased pregnancy loss (OR = 1.64, P = 0.04) compared to those without an abnormal LP. In summary, AI outcomes were improved in multiparous cows that had early CLA and in cows of both parity groups that had at least one normal LP before first AI. However, primiparous cows that had at least one abnormal LP had reduced AI outcomes. Relationships between early postpartum luteal activity and AI outcomes were inconsistent between primiparous and multiparous cows.

Effects of prepartum oilseed supplements on subclinical endometritis, pro- and anti-inflammatory cytokine transcripts in endometrial cells and postpartum ovarian function in dairy cows.

Postpartum uterine infections affect ovarian function and delay ovulation in cattle. As dietary fats can affect immune cell function, we investigated the influence of prepartum diets on postpartum uterine inflammatory status (UIS) as assessed 25±1 days postpartum by endometrial cytology (normal: ≤8% polymorphonuclear cells (PMN) vs subclinical endometritis (SCE): >8% PMN) and associations between SCE, pro- and anti-inflammatory cytokine gene expression and ovarian function. During the last 5 weeks of gestation, dairy cows received a diet supplemented with 8% rolled sunflower (n=10) or canola seed (n=9) or no oilseed (n=9). Ovaries were scanned until 35 days postpartum. Prepartum diets did not influence SCE, but a preovulatory-size follicle developed sooner (P≤0.05), the interval to first ovulation was shorter and the proportion of cows ovulating within 35 days postpartum was greater in the sunflower seed group. Although mRNA expression of cytokines was not affected by diet, cows with SCE had higher (P≤0.05) expression of interleukin-1ß (IL1B), interleukin-8 (CXCL8), IL10 and tumour necrosis factor-α (TNF) than normal cows. The interval (mean ± s.e.m.) from calving to preovulatory-size follicle was shorter (P≤0.05) in normal (13.2±0.9 days) than SCE cows (18.7±1.4 days). In summary, a prepartum diet supplemented with sunflower seed positively influenced postpartum ovarian function without affecting UIS or pro- and anti-inflammatory cytokine gene expression in endometrial cells.

Uterine Microbiota Progression from Calving until Establishment of Metritis in Dairy Cows.

The objective of this study was to evaluate the progression of the uterine microbiota from calving until establishment of metritis. Uterine swabs (n = 72) collected at 0, 2, and 6 ± 2 days postpartum (dpp) from 12 metritic and 12 healthy cows were used for metagenomic sequencing of the 16S rRNA gene on the Illumina MiSeq platform. A heat map showed that uterine microbiota was established at calving. The microbiota changed rapidly from 0 to 6 ± 2 dpp, with a decrease in the abundance of Proteobacteria and an increase in the abundance of Bacteroidetes and Fusobacteria, which were dominant in metritic cows. Uterine microbiota composition was shared; however, metritic and healthy cows could be discriminated using relative abundance of bacterial genera at 0, 2, and 6 ± 2 dpp. Bacteroides was the main genus associated with metritis because it was the only genus that showed significantly greater abundance in cows with metritis. As the abundance of Bacteroides organisms increased, the uterine discharge score, a measure of uterine health, worsened. Fusobacterium was also an important genus associated with metritis because Fusobacterium abundance increased as Bacteroides abundance increased and the uterine discharge score worsened as the abundance increased. The correlation with uterine discharge score and the correlation with Bacteroides or Fusobacterium showed that other bacteria, such as Helcoccocus, Filifactor, and Porphyromonas, were also associated with metritis. There were also bacteria associated with uterine health, such as "Candidatus Blochmannia," Escherichia, Sneathia, and Pedobacter.

Low-dose natural prostaglandin F2α (dinoprost) at timed insemination improves conception rate in dairy cattle.

The primary objective was to determine if low doses of PGF2α (dinoprost) given intramuscularly (im) concurrent with timed artificial insemination (TAI) would improve conception rates in dairy cattle. A secondary objective was to determine if body condition score (BCS) and parity would influence conception rates, either independently or in interaction with PGF2α treatment. In experiment I, 307 lactating Holstein cows were randomly assigned to receive either 5-mg PGF2α im (PGF2α treated, n = 154) or 0-mg PGF2α (control, n = 153) at TAI (Day 0). Blood samples were obtained on Days -10, -3, 0, and 7 to determine plasma progesterone (P4) concentrations. Pregnancy was confirmed 30 to 32 days after insemination by transrectal ultrasonography. In experiment II, 451 cows were randomly assigned to receive either 10-mg PGF2α im (PGF2α treated, n = 226) or 0-mg PGF2α (control, n = 225) at TAI, and pregnancy was confirmed 45 to 50 days after TAI by palpation per rectum. Pregnancy data were analyzed by CATMOD (SAS). In experiment I, PGF2α treatment, BCS, and parity did not affect conception rate (35.7% vs. 37.0% for PGF2α treated vs. control; P > 0.05). However, in experiment II, conception rates were higher in cows given 10-mg PGF2α than those in control cows (45.8% vs. 36.0%; P < 0.05), in cows with high BCS than in cows with low BCS (52.1% vs. 30.4%; P < 0.01), and in primiparous than in multiparous cows (47.6% vs. 34.4%; P < 0.01), but their interaction with PGF2α treatment did not affect conception rates. In summary, 5 mg of PGF2α given im concurrent with TAI failed to enhance conception rate in lactating dairy cows, whereas 10 mg of PGF2α significantly increased conception rate.