A Pilot Study to Evaluate the Potential of Melatonin Implants to Control Cyclicity in the Bitch

Simple Summary Current methods to control the reproductive cycle in the bitch are associated with problematic side effects. Melatonin plays a role in the regulation of reproduction in several species. It has been used to control the reproductive cycle in species with seasonal reproduction. The ancestor of the dog, the grey wolf, has strict seasonal reproduction with breeding in early spring. In contrast to the wolf, the domestic dog is a non-seasonal breeder. It is still not known whether melatonin is involved in control of cyclicity in either the wolf or the domestic dog. The aim of this study was, therefore, to evaluate whether a long-acting melatonin implant would be a safe alternative for short-term postponement of heat in the bitch. Five beagle bitches were treated with melatonin implants while another four bitches were untreated controls. There was no effect of treatment with melatonin implants on the cyclicity in this study. Implants with 18 mg are, therefore, not likely to be a useful method to control cyclicity in the bitch, in contrast to some other species. It is still not known whether melatonin is involved in regulation of the oestrus cycle in the domestic dog. In short-day breeders such as the sheep, melatonin stimulates oestrus activity; in contrast, a high serum concentration of melatonin inhibits oestrus in long-day breeders such as the cat. Therefore, implants with melatonin have been used to suppress or induce oestrus depending on the species. The aim of this pilot study was to evaluate if melatonin could be an alternative to control the reproductive cycle in the bitch. Nine beagle bitches were observed for three oestrus cycles. Five beagle bitches were treated with 18 mg melatonin implants on average 27 days before the next expected oestrus based on the previous interoestrus interval. Four bitches served as untreated controls. Blood samples for evaluation of serum melatonin were collected at the time of assignment to treatment or control group and 1-4 weeks thereafter. Clinical signs and vaginal smears were used to follow the cycle. Melatonin varied significantly with bitch (p 0.05). In conclusion, treatment with 18 mg melatonin implants approximately one month before expected oestrus is not likely to be a useful method to control cyclicity in the bitch. It is still not known if melatonin is involved in regulation of the oestrus cycle in the domestic dog

Sensitive and broadband measurement of dispersion in a cavity using a Fourier transform spectrometer with kHz resolution

Optical cavities provide high sensitivity to dispersion since their resonance frequencies depend on the index of refraction. We present a direct, broadband, and accurate measurement of the modes of a high finesse cavity using an optical frequency comb and a mechanical Fourier transform spectrometer with a kHz-level resolution. We characterize 16000 cavity modes spanning 16 THz of bandwidth in terms of center frequency, linewidth, and amplitude. We retrieve the group delay dispersion of the cavity mirror coatings and pure N${_2}$ with 0.1 fs${^2}$ precision and 1 fs${^2}$ accuracy, as well as the refractivity of the 3{\nu}1+{\nu}3 absorption band of CO${_2}$ with 5 x 10${^{-12}}$ precision. This opens up for broadband refractive index metrology and calibration-free spectroscopy of entire molecular bands

Evaluation of Canine Neonatal Health by Breeders: A Prospective Questionnaire Study on the Association between Neonatal Scores (Modified APGAR), Parturition, Birth Weight, Growth, and Puppy Mortality

Simple Summary Puppy mortality is a widespread problem in small animal medicine. Apgar scoring, adapted for puppies performed by trained veterinary staff, was previously shown to be useful in identifying newborn puppies with an increased risk of mortality. The majority of puppies, however, are born in a home or kennel environment. In most whelpings, early evaluations and interventions are performed by the breeder. Therefore, we wanted to evaluate if a modified Apgar protocol for neonatal monitoring would be usable by breeders in a home environment. Our aim was to evaluate potential associations between neonatal scores, delivery times, birth weights, growth rates, and puppy mortality. Twenty-one bitches gave birth to 113 puppies by vaginal delivery. Neonatal scores were related to puppy mortality. Puppies with low neonatal scores had a longer expulsion interval and lower viability. Mortality was higher in puppies with a low relative birthweight. Puppies with a negative growth rate the first two days after parturition did not have a significantly higher risk of mortality in this study. Our results indicate that a modified and simplified neonatal scoring, performed by breeders approximately 5 min after birth, could be useful to identify puppies at risk of mortality.Abstract Mortality of neonatal puppies is a widespread problem in small animal medicine. Neonatal monitoring, according to standardized protocols, can be useful for identifying puppies that are at risk of mortality. Prompt intervention on weak puppies could increase survival rates. Apgar scoring adapted for puppies has been demonstrated to be associated with mortality and is usually performed by trained veterinary staff. The majority of puppies, however, are born in a home or kennel environment and not at a veterinary clinic. Our aims were, therefore, to evaluate if a modified protocol for neonatal monitoring would be usable by breeders in a home environment. We wanted to evaluate potential associations between modified Apgar scores, birth weights, delivery times, growth rates, and puppy mortality. Modified Apgar scores were related to the viability of live-born puppies (p < 0.0013). The viability and expulsion time of each puppy were significantly related (p = 0.010 with all puppies included and p = 0.038 with only live-born puppies included). Viability was significantly related to relative birthweight (p < 0.01). Puppies with a negative growth rate the first two days after parturition did not have a significantly higher risk of mortality. In conclusion, a modified and simplified Apgar scoring performed by breeders approximately 5 min after birth was associated with puppy mortality