To what extent does photoperiod affect cattle reproduction? Clinical perspectives of melatonin administration

The seasonality of reproduction in most mammals is dictated by photoperiod, temperature and nutrition. Melatonin, mainly synthesized in the pineal gland, is generally accepted as the active mediator of photoperiod responses including reproduction. While non-pregnant heifers and cows show continuous sexual activity and are therefore not seasonal breeders, it has been suggested that photo-periodicity may influence the appearance of puberty in heifers and the onset of parturition. Further, the light/dark ratio may influence endocrine patterns of gestation and a shorter light period correlates with the incidence of twin pregnancies. This review considers specific aspects of the effects of photoperiod and melatonin on reproduction in dairy cattle and discusses the clinical applications of melatonin

Učinak primjene melatonina prije teljenja na izlučivanje mlijeka tijekom laktacije u mliječnih krava

This study evaluated the effects of melatonin administration 60 days prior to expect calving (drying-off period) on milk yield during the next lactation. Sixty dairy cows were treated with subcutaneous melatonin implants during summer (n=30) or winter (n=30) period. Another 60 animals were not treated and served as the control. There were no differences in the average milk yield between treated and untreated animals (44.5±3.7 and 44.8±5.0 kg/day for melatonin and control cows, respectively). There was an effect of season with a higher winter milk yield than in summer (43.8±5.0 and 47.1±3.0 kg/day for melatonin and control groups, respectively). The interaction between melatonin and season showed no significant effect; however, during winter, milk yield tended to be higher (P=0.06) in control cows than in melatonin treated cows (45.3±3.7 and 49.2±3.0, respectively). This study indicates that treatment with melatonin prior to calving did not modify milk yield during the following lactation. Only a tendency for a reduction in milk yield during winter was observed in melatonin treated cows.U ovom istraživanju procjenjivan je učinak primjene melatonina 60 dana prije očekivanog teljenja (razdoblje isušivanja) na proizvodnju mlijeka tijekom kasnije laktacije. Šezdeset mliječnih krava tretirano je potkožnim implantatima melatonina tijekom ljetnog (n=30), odnosno zimskog (n=30) razdoblja. Drugih 60 životinja nije tretirano i one su poslužile kao kontrola. Nije bilo razlika u prosječnoj proizvodnji mlijeka između tretiranih i netretiranih životinja (44,5±3,7 kg/ dan u krava tretiranih melatoninom, odnosno 44,8±5,0 kg/dan u kontrolnih krava). Postojao je učinak sezone, pri čemu je proizvodnja mlijeka bila veća zimi u odnosu na ljeto (43,8±5,0 kg/ dan u krava tretiranih melatoninom, odnosno 47,1±3,0 kg/dan u kontrolnoj skupini). Interakcija između melatonina i sezone nije pokazala značajniji učinak, ali tijekom zimske sezone proizvodnja mlijeka u kontrolnih krava bila je veća (P=0,06) u odnosu na krave tretirane melatoninom (45,3±3,7 u kontrolnoj skupini, odnosno 49,2±3,0 u krava tretiranih melatoninom). Ova studija ukazuje da tretman melatoninom prije teljenja ne mijenja proizvodnju mlijeka tijekom kasnije laktacije. Primijećena je samo tendencija smanjenja proizvodnje mlijeka u zimskoj sezoni u krava tretiranih melatoninom

Effect of melatonin administration prior to calving on milk secretion in the next lactation in dairy cows

This study evaluated the effects of melatonin administration 60 days prior to expect calving (drying-off period) on milk yield during the next lactation. Sixty dairy cows were treated with subcutaneous melatonin implants during summer (n=30) or winter (n=30) period. Another 60 animals were not treated and served as the control. There were no differences in the average milk yield between treated and untreated animals (44.5±3.7 and 44.8±5.0 kg/day for melatonin and control cows, respectively). There was an effect of season with a higher winter milk yield than in summer (43.8±5.0 and 47.1±3.0 kg/day for melatonin and control groups, respectively). The interaction between melatonin and season showed no significant effect; however, during winter, milk yield tended to be higher (P=0.06) in control cows than in melatonin treated cows (45.3±3.7 and 49.2±3.0, respectively). This study indicates that treatment with melatonin prior to calving did not modify milk yield during the following lactation. Only a tendency for a reduction in milk yield during winter was observed in melatonin treated cows

Relationship between adipose tissue dysfunction, Vitamin D deficiency and the pathogenesis of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease ( NAFLD) is the most common chronic liver disease worldwide. Its pathogenesis is complex and not yet fully understood. Over the years many studies have proposed various pathophysiological hypotheses, among which the currently most widely accepted is the "multiple parallel hits" theory. According to this model, lipid accumulation in the hepatocytes and insulin resistance increase the vulnerability of the liver to many factors that act in a coordinated and cooperative manner to promote hepatic injury, inflammation and fibrosis. Among these factors, adipose tissue dysfunction and subsequent chronic low grade inflammation play a crucial role. Recent studies have shown that vitamin D exerts an immune-regulating action on adipose tissue, and the growing wealth of epidemiological data is demonstrating that hypovitaminosis D is associated with both obesity and NAFLD. Furthermore, given the strong association between these conditions, current findings suggest that vitamin D may be involved in the relationship between adipose tissue dysfunction and NAFLD. The purpose of this review is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to adipose tissue dysfunction, and in the pathophysiology linking vitamin D deficiency with NAFLD and adiposity, together with an overview of the evidence available on the clinical utility of vitamin D supplementation in cases of NAFLD

Effect of utilization of single or double prostaglandin administration within an ovsynch fixed-time artificial insemination protocol during summer season in dairy cows

This study investigated the fertility of dairy cows during summer season after treatment with a single or double PGF2α in a progesterone (P4)-based Ovsynch protocol for fixed-time artificial insemination (FTAI). The data were compared to a treatment effectuated during winter season. Two groups of 60 dairy cows each were randomly assigned on day 60 post-partum to single PGF2α or double PGF2α group. At removal of the P4 treatment the single PGF2α group received a single dose and the double PGF2α group received two doses of PGF2α at 24 hours apart. In each group, 30 cows were treated during the summer (June, July and August) and 30 cows during the winter (December, January and February) season. During summer season a double PGF2α dose did not influence pregnancy rate at FTAI but improved cumulative pregnancy rate 60 days after FTAI (43% vs 69% for single PGF2α and double PGF2α administration, respectively; P<0.05). During winter season the single or double PGF2α administration did not modify PR or cumulative PR. In conclusion, during summer the utilization of a double instead of single PGF2α treatment into a P4-based Ovsynch-FTAI protocol did not increase pregnancy rate at FTAI but improved cumulative pregnancy rate

Thermal Mechanisms Preventing or Favoring Multiple Ovulations in Dairy Cattle

While cows are predominantly monovular, over the past 30 years the incidence of multiple ovulations and thus twinning has increased considerably alongside milk production. Multiple pregnancies are not desirable as they negatively affect the health of cows and the herd economy. Although causal mechanisms associated with multiple ovulations have been extensively revised, the process of multiple ovulations is not well understood. Recent studies on the thermal biology of the reproductive system have shown how thermal mechanisms may prevent or favor multiple ovulations. This review focuses on this relationship between thermal dynamics and multiple pregnancies. Cooling of the pre-ovulatory follicle is able to regulate ovulation. In effect, pre-ovulatory local cooling of the female reproductive system favors male and female gamete maturation and promotes fertilization. Thermal stress is proposed here as a model of stress. Periods of high ambient temperature affect the processes of pre-ovulatory follicular cooling and multiple ovulations. While the ratio between unilateral and bilateral multiple pregnancies is normally close to one, under heat stress conditions, this ratio may be 1.4 favoring unilateral multiple pregnancies. A ratio approaching unity is here proposed as an indicator of cow wellbeing.This research was funded by “Fondo Locale per la Ricerca-FIL 2020/2021” University of Parma, Italy (coordinator F.D.R.)

physiological weight loss in newborn puppies of boxer breed

In the first days after birth is common to see weight loss in puppies that should not exceed 10% of body weight at birth. The main causes of weight loss are urine and meconium issued followed by non-recovery of fluids expelled. The aims of the study were to check and outline growth curves in boxer breed during the first two week of life. In our study between 3th and 5th day after birth puppies retrieved the weight and got back a gain that leads to double in two weeks. We observed a mean weight loss of 11.26 g (2.27%) between the first two days of life, subsequently they recovered the birth weight on day four. In our study puppies that regained the birth weight earlier were the puppies with higher weight at birth and were the heaviest at day 13

Postotak koncepcije nakon primjene Ovsynch protkola s točno određenim vremenom umjetnog osjemenjivanja s aplikacijom egzogenog progesterona u cikličnih mliječnih krava tijekom toplog i hladnog razdoblja godine

Progesterone plasma levels during the warm period of the year (summer) are more variable and this can induce a reduction in the fertility of dairy cows. Therefore, the aim of this study is to investigate the effect of the combined use of progesterone supplements with an Ovsynch and FTAI protocol on conception rates during the summer in cows. The data were compared with treatments carried out during the cold season (winter). In total, 120 cows underwent oestrus synchronization by using an Ovsynch and FTAI protocol. After this, one group of 60 cows received progesterone supplements and another group of 60 cows did not. In each group, 30 cows were treated during the summer and 30 cows were treated during the winter. All cows were pre-synchronized with PGF2α 25 days and 11 days before starting the Ovsynch protocol. The conception rate at days 30 and 40 post-insemination was not changed by the Ovsynch protocol being supplemented with progesterone. No interaction between progesterone supplementation and the season (winter or summer ) was observed (P=0.17). The results of the study indicate that in cyclic cows with a functional corpus luteum the supplementation of the Ovsynch- FTAI protocol with progesterone did not improve the conception rate during the warm or cold seasons.Koncentracije progesterona u plazmi u mliječnih krava tijekom toplog razdoblja godine (ljeto) više variraju što može prouzročiti njihovu smanjenu plodnost. Stoga je cilj ovoga rada bio istražiti učinak aplikacije egzogenog progesterona u ovsynch protokolu u kombinaciji s točno određenim vremenom umjetnog osjemenjivanja (TOVO) na postotak koncepcije u mliječnih krava tijekom ljetnog razdoblja. Podatci su bili uspoređeni s istom kombinacijom protokola tijekom hladnog razdoblja godine (zima). Ukupno je u 120 krava sinkroniziran estrus klasičnim ovsynch i TOVO protokolom. Nakon toga, u 60 krava je apliciran egzogeni progesteron, dok u ostalih 60 krava nije apliciran spomenuti pripravak. U svakoj je skupini 30 krava tretirano tijekom ljeta i 30 krava tijekom zimskog razdoblja. Sve su krave bile podvrgnute postupku presinkronizacije s PGF2α 25 dana i 11 dana prije početka ovsynch protokola. Aplikacija egzogenog progesterona u kombinaciji s ovsynch protokolom 30. i 40. dana nakon umjetnog osjemenjivanja nije utjecala na postotak koncepcije. Nije ustavljena značajna povezanost između dodatka egzogenog progesterona i godišnjeg doba (zima ili ljeto)(P=0.17). Rezultati ovog istraživanja pokazali su da aplikacijom egzogenog progesterona u kombinaciji s ovsynch-TOVUO protokolom nije poboljšao postotak koncepcije u krava s cikličnom aktivnosti jajnika (funkcionalno žuto tijelo) tijekom toplog ili hladnog dijela godine

Učinak primjene melatonina prije teljenja na izlučivanje mlijeka tijekom laktacije u mliječnih krava

This study evaluated the effects of melatonin administration 60 days prior to expect calving (drying-off period) on milk yield during the next lactation. Sixty dairy cows were treated with subcutaneous melatonin implants during summer (n=30) or winter (n=30) period. Another 60 animals were not treated and served as the control. There were no differences in the average milk yield between treated and untreated animals (44.5±3.7 and 44.8±5.0 kg/day for melatonin and control cows, respectively). There was an effect of season with a higher winter milk yield than in summer (43.8±5.0 and 47.1±3.0 kg/day for melatonin and control groups, respectively). The interaction between melatonin and season showed no significant effect; however, during winter, milk yield tended to be higher (P=0.06) in control cows than in melatonin treated cows (45.3±3.7 and 49.2±3.0, respectively). This study indicates that treatment with melatonin prior to calving did not modify milk yield during the following lactation. Only a tendency for a reduction in milk yield during winter was observed in melatonin treated cows.U ovom istraživanju procjenjivan je učinak primjene melatonina 60 dana prije očekivanog teljenja (razdoblje isušivanja) na proizvodnju mlijeka tijekom kasnije laktacije. Šezdeset mliječnih krava tretirano je potkožnim implantatima melatonina tijekom ljetnog (n=30), odnosno zimskog (n=30) razdoblja. Drugih 60 životinja nije tretirano i one su poslužile kao kontrola. Nije bilo razlika u prosječnoj proizvodnji mlijeka između tretiranih i netretiranih životinja (44,5±3,7 kg/ dan u krava tretiranih melatoninom, odnosno 44,8±5,0 kg/dan u kontrolnih krava). Postojao je učinak sezone, pri čemu je proizvodnja mlijeka bila veća zimi u odnosu na ljeto (43,8±5,0 kg/ dan u krava tretiranih melatoninom, odnosno 47,1±3,0 kg/dan u kontrolnoj skupini). Interakcija između melatonina i sezone nije pokazala značajniji učinak, ali tijekom zimske sezone proizvodnja mlijeka u kontrolnih krava bila je veća (P=0,06) u odnosu na krave tretirane melatoninom (45,3±3,7 u kontrolnoj skupini, odnosno 49,2±3,0 u krava tretiranih melatoninom). Ova studija ukazuje da tretman melatoninom prije teljenja ne mijenja proizvodnju mlijeka tijekom kasnije laktacije. Primijećena je samo tendencija smanjenja proizvodnje mlijeka u zimskoj sezoni u krava tretiranih melatoninom

Phenotypical heterogeneity linked to adipose tissue dysfunction in patients with type 2 diabetes

Adipose tissue (AT) inflammation leads to increased free fatty acid (FFA) efflux and ectopic fat deposition, but whether AT dysfunction drives selective fat accumulation in specific sites remains unknown. The aim of the present study was to investigate the correlation between AT dysfunction, hepatic/pancreatic fat fraction (HFF, PFF) and the associated metabolic phenotype in patients with Type 2 diabetes (T2D). Sixty-five consecutive T2D patients were recruited at the Diabetes Centre of Sapienza University, Rome, Italy. The study population underwent clinical examination and blood sampling for routine biochemistry and calculation of insulin secretion [homoeostasis model assessment of insulin secretion (HOMA-β%)] and insulin-resistance [homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (ADIPO-IR)] indexes. Subcutaneous (SAT) and visceral (VAT) AT area, HFF and PFF were determined by magnetic resonance. Some 55.4% of T2D patients had non-alcoholic fatty liver disease (NAFLD); they were significantly younger and more insulin-resistant than non-NAFLD subjects. ADIPO-IR was the main determinant of HFF independently of age, sex, HOMA-IR, VAT, SAT and predicted severe NAFLD with the area under the receiver operating characteristic curve (AUROC)=0.796 (95% confidence interval: 0.65-0.94, P=0.001). PFF was independently associated with increased total adiposity but did not correlate with AT dysfunction, insulin resistance and secretion or NAFLD. The ADIPO-IR index was capable of predicting NAFLD independently of all confounders, whereas it did not seem to be related to intrapancreatic fat deposition; unlike HFF, higher PFF was not associated with relevant alterations in the metabolic profile. In conclusion, the presence and severity of AT dysfunction may drive ectopic fat accumulation towards specific targets, such as VAT and liver, therefore evaluation of AT dysfunction may contribute to the identification of different risk profiles among T2D patients