Effects of 1 or 2 treatments with prostaglandin F2α on subclinical endometritis and fertility in lactating dairy cows inseminated by timed artificial insemination

The objectives of the current study were to investigate the efficacy of PGF_2α as a therapy to reduce the prevalence of subclinical endometritis and improve pregnancy per artificial insemination (P/AI) in cows subjected to a timed artificial insemination (AI) program. A total of 1,342 lactating Holstein dairy cows were allocated randomly at 25 ± 3 d in milk (DIM) to remain as untreated controls (control, n = 454) or to receive a single PGF_2α treatment at 39 ± 3 DIM (1PGF, n = 474) or 2 treatments with PGF_2α at 25 ± 3 and 39 ± 3 DIM (2PGF, n = 414). All cows were enrolled in the double Ovsynch program at 48 ± 3 DIM and were inseminated at 75 ± 3 DIM. A subset of 357 cows had uterine samples collected for cytological examination at 25 ± 3, 32 ± 3, and 46 ± 3 DIM to determine the percentage of polymorphonuclear leukocytes (PMNL). Subclinical endometritis was defined by the presence of ≥5% PMNL. Vaginal discharge score was evaluated at 25 ± 3 DIM and used to define the prevalence of purulent vaginal discharge. Body condition score was assessed at 25 ± 3 DIM. Pregnancy was diagnosed 32 d after AI and reconfirmed 28 d later. At 32 ± 3 DIM, the prevalence of subclinical endometritis was reduced by treatment with PGF_2α at 25 ± 3 DIM in 2PGF (control = 23.5% vs. 1PGF = 28.3% vs. 2PGF = 16.7%); however, this benefit disappeared at 46 ± 3 DIM, and 14% of the cows remained with subclinical endometritis. One or 2 treatments with PGF_2α did not influence P/AI on d 32 or 60 after timed AI, which averaged 39.9 and 35.2%. Similarly, treatment with PGF_2α had no effect on pregnancy loss between 32 and 60 d of gestation (11.9%). Cows diagnosed with both purulent vaginal discharge and subclinical endometritis had the lowest P/AI and the highest pregnancy loss compared with those diagnosed with only 1 of the 2 diseases or compared with cows having no diagnosis of uterine diseases. Interestingly, subclinical endometritis depressed P/AI and increased pregnancy loss only when it persisted until 46 DIM. On d 32 after AI, cows not diagnosed with subclinical endometritis and those that resolved subclinical endometritis by 46 DIM had greater P/AI than those that remained with subclinical endometritis at 46 DIM (45.4 and 40.0 vs. 25.0%, respectively). Similar to P/AI, cows not diagnosed with subclinical endometritis and those that resolved subclinical endometritis by 46 DIM had less pregnancy loss than those with subclinical endometritis at 46 DIM (9.6 and 13.5 vs. 43.9%, respectively). One or 2 treatments with PGF_2α before initiation of the timed AI program were unable to improve uterine health, P/AI, and maintenance of pregnancy in lactating dairy cows. Cows diagnosed with both purulent vaginal discharge and subclinical endometritis had the greatest depressions in measures of fertility at first AI, particularly when subclinical endometritis persisted in the early postpartum period.     

Effect of supplementing essential fatty acids to pregnant nonlactating Holstein cows and their preweaned calves on calf performance,immune response,and health

The objective was to evaluate the effect of supplementing saturated or unsaturated fatty acids (FA) during late gestation of cows and during the preweaning period of calves on growth, health, and immune responses of calves. During the last 8 wk of pregnancy, Holstein cattle (n = 96) were fed no fat supplement (control), a saturated FA (SFA) supplement enriched in C18:0, or an unsaturated FA supplement enriched in the essential FA linoleic acid. Newborn calves were fed a milk replacer (MR) with either low linoleic acid (LLA; coconut oil) or high linoleic acid (HLA; coconut oil and porcine lard) concentration as the sole feedstuff during the first 30 d. A grain mix with minimal linoleic acid was offered between 31 and 60 d of life. At 30 and 60 d of life, concentrations of linoleic acid in plasma were increased in calves born from dams supplemented with essential FA compared with SFA (44.0 vs. 42.5% of total FA) and in calves consuming HLA compared with LLA MR (46.3 vs. 40.8% of total FA). Total n-3 FA concentration was increased in plasma of calves fed HLA compared with LLA MR (1.44 vs. 1.32%) primarily due to increased α-linolenic acid. Prepartum supplementation with SFA tended to improve dry matter intake (48.8 vs. 46.7 kg) and improved average daily gain (0.50 vs. 0.46 kg/d) by calves without affecting efficiency of gain or circulating concentrations of anabolic metabolites or hormones. Increasing mean intake of linoleic acid from approximately 4.6 to 11.0 g/d during the first 60 d of life increased average daily gain (0.50 vs. 0.45 kg/d) without a change in dry matter intake, thus improving feed efficiency (0.63 vs. 0.59 kg of gain/kg of dry matter intake). Improved weight gain in calves fed HLA MR was accompanied by increased or tendency to increase plasma concentrations of glucose (92.7 vs. 89.9 g/dL) and insulin-like growth factor I (59.5 vs. 53.2 g/dL), increased hematocrit (36.0 vs. 34.4%) and concentration of blood lymphocytes (4.61 vs. 4.21 × 10³/μL), lowered plasma concentrations of acid-soluble protein (78.8 vs. 91.3 mg/L) and blood platelets (736 vs. 822 × 10³/μL), and increased production of IFN-γ by peripheral blood mononuclear cells at 30 d of age (48.1 vs. 25.6 pg/mL), possibly indicating an earlier development of the immune system. Partial replacement of coconut oil with porcine lard in MR improved calf performance and some aspects of immunity.     

Effects of method of presynchronization and source of selenium on uterine health and reproduction in dairy cows

The objectives of this study were to evaluate the effects of method of presynchronization and source of supplemental Se on uterine health and reproductive performance of lactating dairy cows. Holstein cows (n = 512) were assigned randomly to 2 methods of presynchronization, Presynch (2 PGF_2a given 14 d apart) or CIDR-PS (controlled internal drug releasing inserted for 7 d with an injection of PGF_2a at removal) and 2 sources of Se, sodium selenite (SS) or selenized yeast (SY) supplemented at 0.3 mg/kg from 25 d before calving to 80 d in milk (DIM) arranged in a 2 × 2 factorial. Cows were inseminated following the Ovsynch protocol (d 0 GnRH, d 7 PGF_2a, d 9 GnRH, timed artificial insemination (AI) 12 h after the final GnRH) starting at 12 and 3 d after Presynch and CIDR-PS, respectively. Cows were diagnosed for pregnancy at 28, 42, and 56 d after AI. Source of Se did not influence uterine health and resumption of cyclicity, but fewer CIDR-PS than Presynch cows were cyclic at the beginning of the Ovsynch, although differences in the proportion cyclic may have been caused by the timing when corpus luteum evaluations were performed in the different pre-synchronization treatments. Ovulatory responses were not influenced by source of Se. However, the CIDR-PS increased ovulation to the first GnRH, double ovulation to the final GnRH, and size of ovulatory follicle at PGF_2a and final GnRH of the Ovsynch, but did not influence ovulation at the final GnRH of the Ovsynch. Concentrations of estradiol during the Ovsynch increased with follicle diameter and were greater for cows receiving CIDR-PS than Presynch, but they were not influenced by source of Se. Pregnancy per AI on d 28 (32.7%), 42 (28.5%), and 56 (25.9%) after AI, and pregnancy loss (20.5%) from 28 to 56 d were not influenced by source of Se or method of presynchronization. Although cows receiving CIDR-PS had an increased incidence of ovulation to the first GnRH (73.2 vs. 57.8%) and double ovulation to the final GnRH of the Ovsynch (18.7 vs. 9.0%), both of which enhanced pregnancy, the CIDR-PS protocol did not improve pregnancy per AI or reduce pregnancy loss compared with presynchronization with PGF_2a alone.     

Performance improvements of self-tuning controllers by multistep horizons: The MUSMAR approach

The problem of adaptively controlling a linear multivariable plant according to a quadratic cost functional defined over a control horizon of arbitrary length is discussed. In this context, the proposed algorithm, referred to by the acronym MUSMAR, is shown to be a natural generalization of standard self-tuning controllers. By increasing the control horizon length, the MUSMAR closely approximates a steady-state LQG controller inheriting the intrinsic robustness of LQG design. Analysis and simulations give evidence of several attractive features of the MUSMAR self-tuner when applied to plants for which standard adaptive controllers fail to converge or yield an unacceptable performance.     

Plasma anti-Müllerian hormone in adult dairy cows and associations with fertility

The objectives of this study were to identify factors associated with concentrations of anti-Müllerian hormone (AMH) in plasma of dairy cows and to investigate the relationships between plasma AMH and fertility responses during a 100-d breeding season. Lactating cows, 1,237 in 2 seasonally calving herds, had estrous cycles presynchronized and were enrolled in a timed artificial insemination (AI) protocol. All cows were inseminated on the first day of breeding season, considered study d 0. Blood was sampled on d −8 and analyzed for concentrations of AMH and progesterone. From d 19 to 35, detection of estrus was performed daily and cows detected in estrus were reinseminated. On d 36, bulls were placed with cows for 65 d of natural service breeding. Factors identified to be associated with concentrations of AMH in plasma were breed of the cow and lactation number. Concentrations of AMH were greater for Jerseys, followed by crossbreds, and then Holsteins. Cows on lactations 2 and 3 had greater concentrations of AMH than those on lactations 1 and ≥4. Although pregnancy per AI at the timed AI was not associated with concentrations of AMH, cows with low AMH had greater detection of estrus at timed AI, and the latter benefited pregnancy per AI, particularly in cows that had low progesterone at the beginning of the synchronization protocol. Pregnancy loss between gestation d 30 and 65 was greater in cows with low AMH compared with those with intermediate or high AMH. Return to estrus in cows that failed to become pregnant from the timed AI was not associated with AMH, but pregnancy rate in cows bred on estrus (reinsemination + natural service) was associated positively with AMH. In conclusion, breed and lactation number were identified to be associated with concentrations of AMH in plasma. Concentration of AMH was associated positively with maintenance of pregnancy at the first postpartum AI and with pregnancy rate in cows inseminated after detection of spontaneous estrus. Synchronization of ovulation might override positive associations between AMH and fertility.     

Mining User Preferences,Page Content and Usage to Personalize Website Navigation

The growing availability of information on the Web has raised a challenging problem: can a Web-based information system tailor itself to different user requirements with the ultimate goal of personalizing and improving the users' experience in accessing the contents of a website? This paper proposes a new approach to website personalization based on the exploitation of user browsing interests together with content and usage similarities among Web pages. The outcome is the delivery of page recommendations which are strictly related to the navigational purposes of visitors and their actual location within the cyberspace of the website. Our approach has been used effectively for developing a non-invasive system which allows Web users to navigate through potentially interesting pages without having a basic knowledge of the website structure.     

Programming with non-determinism in deductive databases

While non-determinism has long been established as a key concept in logic pro-gramming, its importance in the context of deductive databases was recognized only recently. This paper provides an overview of recent results on this topic with the aim of providing an introduction to the theory and practice of non-determinism in deductive databases. In particular we (i) recall the main results linking non-deterministic constructs in database languages to the theory of data complexity and the expressibility hierarchy of query languages; (ii) provide a reasoned introduction to effective programming with non-deterministic constructs; (iii) compare the usage of non-deterministic constructs in languages such as LDL++ to that of traditional logic programming languages; (iv) discuss the link between the semantics of logic programs with non-deterministic constructs and the stable-model semantics of logic programs with negation.     

Parallel-local anodic oxidation of silicon surfaces by soft stamps

We investigate the fabrication of nanometric patterns on silicon surfaces by using the parallel-local anodic oxidation technique with soft stamps. This method yields silicon oxide nanostructures 15?nm high, namely at least five times higher than the nanostructures made with local anodic oxidation using atomic force microscopy, and thanks to the size of the stamp enables one to pattern the surface across a centimetre length scale. To implement this technique, we built a machine to bring the metallized polydimethylsiloxane stamp in contact with the silicon surface, subsequently inserted in a sealed chamber with controlled relative humidity. The oxide nanostructures are fabricated when a bias voltage of 36?V is applied between the stamp and the silicon for 2?min, with a relative humidity of 90%. The flexibility of the stamp enables a homogeneous conformal contact with the silicon surface, resulting in an excellent reproducibility of the process. Moreover, by means of two subsequent oxidations with the same stamp and just rotating the sample, we are able to fabricate complex nanostructures. Finally, a detailed study of the oxidation mechanism, also using a finite element analysis, has been performed to understand the underlying mechanism.     

Flow-boiling of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube

Flow boiling heat transfer coefficients of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube (6 mm I.D., 6 m length) were measured at a refrigerant mass flux of about 360 kg/m² s varying the evaporating pressure within the range 3–12 bar, with heat fluxes within the range 11–21 kW/m². The experimental data are discussed in terms of the heat transfer coefficients as a function of the vapour quality. The experimental results clearly show that the heat transfer coefficients of R134a are always higher than those pertaining to R22 (from a minimum of +6 to a maximum of +45%).