Lack Of Cyclicity Research Articles

Infertility In Queens: Clinical approach, experiences and challenges.

It is not easy for a veterinarian to determine the cause of infertility in a queen. The simplest method is to start by investigating the most common causes and then progress by successive elimination to the less common causes. For example, mating problems are commonly responsible for reproductive failure, and owners should be particularly vigilant in checking that the mating is progressing satisfactorily. Frequently, a veterinarian may have to determine, among other things, if there is a uterine or hormonal disorder or if an infectious pathology may be involved. In the case of a queen that is not cycling, it is important to differentiate a lack of onset of puberty in a young queen from a lack of cyclicity in an adult queen. This review sets out a practical, step-by-step approach that veterinarians can follow, starting with the most common causes of infertility in queens and moving towards more rare or specific causes. Simple techniques such as vaginal smears are essential to determine if a queen that is ready to be mated is in full oestrus, if a queen is cycling or not and to diagnose inflammation of the genital tract. Veterinarians should be familiar with the peculiarities of the swabbing technique in cats, as well as the interpretation of feline vaginal cytology. Progesterone assays are useful on many occasions in the diagnosis pathway. A laboratory capable of performing karyotypes should ideally be available. Finally, it is important to be able to perform an ultrasound examination of the ovaries and uterus in a queen. Although it appears that infertility is a problem among purebred queens, there is a lack of knowledge in this area and too few published studies. Some causes of feline infertility remain poorly investigated.

Forecasting the number of passengers serviced at the maritime ports in Bulgaria

The maritime transport in Bulgaria is controlled and coordinated by the Executive Agency Maritime administration. This institution is a legal entity on budget support to the Ministry of transport, information technology and communications, a second level user of budget credits, based in Sofia with regional offices in Bourgas, Varna, Lom and Rousse (where are the Bulgarian major ports) . EAMA status is regulated by the Merchant Shipping Code - Art. 360, para.1. The problem of forecasting in the new strategic documents is crucial to the formation of proper infrastructure policy which has to be innovative and for the future strategic development of the tourism in the country. This paper is aimed at presenting the lack of real forecasting in many of the strategic documents and projects adopted for the development of the maritime transport in Bulgaria (i.e. Directive 2008/106/EC of European Parliament and Council on the minimum level of training of seafarers; Ordinance No 9 of 2013 on the requirements for operational suitability of ports and specialised port facilities; Ordinance No 10 of 2014 on the scope and content, preparation, approval and amendment of the general plans of the public transport ports). There are also many Mutual Agreements for Recognition of Seafarers certificates. The paper provides a practical example for the use of the so called single or simple exponential smoothing without the presence of any seasonality and the lack of cyclicity on the number of passengers arrivals at the Bulgarian maritime ports.

Factors influencing breeding success, ovarian cyclicity, and cub survival in zoo-managed tigers (Panthera tigris)

Understanding factors that influence reproduction and offspring survival in zoo populations is critical for management of threatened and endangered species. Examination of long-term data (1989–2011) compiled from the Association of Zoos and Aquarium's zoo-managed tiger breeding program provides the basis for a more thorough understanding of reproduction and scientifically based decisions for effective population management in this endangered felid. Biological and management-related factors that could influence tiger breeding success and cub survival were evaluated using logistic mixed models. Breeding success improved with female age until approximately age five, then declined thereafter. Experienced female breeders had greater breeding success than inexperienced females. Litter size was most predictive of cub survival, with average-sized litters (3–4 cubs) experiencing the highest proportional survival. Management-related factors, such as whether the breeding institution had a recent tiger litter and whether both animals were already located at the same institution, also influenced breeding success and cub survival. These results highlight the importance of institutional husbandry experience and the need to retain knowledge through staff turnovers to achieve optimal reproductive success. Using fecal estrogen data, frequency of ovarian cyclicity and mean cycle length did not differ by female age or parity; thus, lack of cyclicity and/or increased cycle duration are not likely explanations for declining breeding success with age. These results provide valuable reproductive information that should improve scientific management of zoo-based tiger populations.

Serum thyroid hormones and performance of offspring in ewes receiving propylthiouracil with or without melatonin

Two experiments were conducted during mid-gestation to examine effects in ewes of propylthiouracil (PTU) treatment alone or with melatonin on serum thyroid hormones, postpartum reproduction, and lamb performance. In the first experiment, beginning on day 0 (first day of treatment when all animals were 72.2 ± 0.9 days of gestation), ewes received daily treatments (gavage) consisting of either 0 mg ( n = 6) or 40 mg ( n = 6) PTU/kg body weight/day for 15 days. After 15 days, the 40 mg dosage was decreased to 20 mg/kg body weight for an additional 20 days (35 days of PTU). Serum thyroxine (T4) did not differ ( P > 0.10) between groups through day 4; but on day 5, control females had a serum value of 67 ng/ml compared with 46 (±5) ng/ml for PTU-treated ewes ( P = 0.02). On the last day that 40 mg of PTU was administered, serum T4 averaged 67 and 7 (±5) ng/ml ( P < 0.001) in the two respective groups. Serum T4 remained low and was 80 and 1 ng/ml ( P < 0.001) in control and treated ewes on day 34. Serum T4 rose gradually after PTU but remained different from that observed in control ewes through day 48. Lambs from control and treated ewes had similar ( P = 0.46) T4 values at birth but lambs from PTU-treated ewes had lower ( P = 0.03) birth weights than did those from control ewes. Serum progesterone (P4) after parturition indicated a lack of cyclicity in all ewes. In the second experiment, beginning on day 0 (76.8 ± 4.7 days of gestation), ewes received PTU as in Experiment 1. In addition, after 15 days of PTU, melatonin was given (i.m. injections at 5 mg/day) for 30 days. Propylthiouracil decreased ( P ≤ 0.05) serum T4 on days 25 through 41 of the treatment period. Serum T3 was lower ( P < 0.05) in PTU-treated ewes from day 8 through the end of PTU administration. Postpartum P4 was below 1 ng/ml on all days indicating acyclicity. Lamb body weight and serum IGF-I were similar ( P > 0.60) for lambs born to control and treated ewes. Female offspring of PTU + melatonin-treated dams reached puberty, became anestrus, and returned to cyclicity at similar ( P > 0.10) times to contemporary ewe lambs. Results indicate that 40/20 mg PTU alone or with melatonin does not induce cyclicity after lambing in spring lambing ewes and has little effect on offspring performance.

Effect of riboflavin deficiency on estrous cyclicity in pigs.

Previous studies have shown that riboflavin is needed for reproduction. A deficiency of this vitamin causes a lack of cyclicity and interferes with pregnancy. Because the exact means by which riboflavin affects reproduction is unknown, we conducted two experiments to determine the effect of a riboflavin deficiency on plasma and urinary sex steroids. Riboflavin status was measured by the determination of erythrocyte glutathione reductase activity coefficients (EGR-AC). In experiment 1, 13 male and 12 female pigs were bled by venipuncture for 3 consecutive days to determine if the EGR-AC was affected by the sex of the animal and if the EGR-AC fluctuated from day to day. Neither sex nor day of sampling significantly affected EGR-AC. The mean EGR-AC was 1.43± 0.11. In experiment 2, 20 crossbred cycling gilts were randomly allotted to two treatments: riboflavin adequate (control) and riboflavin deficient cornstarch-soybean meal diets. Gilts were checked daily for estrus. Blood was obtained by venipuncture at 1000 h every 2 weeks after the establishment of the deficiency. Plasma was frozen at −20°C and assayed for progesterone (P4) and estradiol-17β(E2). After 28 days, the first urine sample from two consecutive days was collected and assayed for estrone sulfate (E1 S) after enzymatic hydrolysis. Gilts on the riboflavin deficient diet became anestrous ∿63 days after the beginning of the experiment. The average time elapsed between consecutive estrous periods increased with length of time on the deficient diet. The control gilts had elevated (P<0.01) plasma P4 levels between Days 4–18 with peak concentrations of 28.3 ± 1.0 ng/ml on Day 12 of the cycle. In contrast, P4 levels in riboflavin deficient gilts were significantly elevated (P<0.001) over control gilts (64.2 ± 1.0 ng/ml). The E2 plasma concentrations in control gilts were low (19.6 ± 1.9 pg/ml) from Days 2–18, but were elevated (64.7 ± 2.3 pg/ml; P<0.01) 2 days before the onset of estrus. The riboflavin deficient gilts displayed significantly elevated E2 levels (82.6 ± 1.8 pg/ml; P<0.001). The E1 S urine concentrations were elevated in the control gilts with peak levels of 22.1 ± 2.3 ng/mg creatinine on Day 20. The riboflavin deficient guts had low E1 S levels throughout the test period (4.1 ± 0.8 ng E1 S/mg creatinine). These data indicate a loss of ovarian cyclicity and the presence of abnormal plasma concentrations and urinary excretion of sex steroids for riboflavin deficient gilts.