Feeding habits of Paralabrax nebulifer (Serranidae) during reproductive and non-reproductive seasons in an adjacent area to Magdalena Bay, Baja California Sur, Mexico

The barred sand bass Paralabrax nebulifer is a commercially important fish off the west coast of Baja California Sur. To assess the diet of this species and variations as a function of sex and reproductive condition, 60 specimens were captured using traps during seven seasonal sampling trips from August 2016 to August 2018 in an adjacent area to Magdalena Bay, Baja California Sur, Mexico. The stomach contents of 50 specimens were obtained (23 males and 27 females). Sex was diagnosed by direct observation of the gonads. Based on the gonadosomatic index, hepatosomatic index, and histological analyses, the reproductive season of the barred sand bass was corroborated for August 2016, April, August, and September 2017, and August 2018, and the non-reproductive season was corroborated for November 2016 and March 2018. The Index of Relative Importance (IRI) was used to classify the main diet components, which comprised three fish species, seven crustacean species, and one mollusk species. According to the IRI, the South American pilchard Sardinops sagax and the red pelagic crab Pleuroncodes planipes were the prey that contributed the most (55%) to the barred sand bass diet. The ANOSIM showed that there were significant differences in the amount and type of prey consumed by sex; the SIMPER analysis revealed that the species contributing the most to differences between the sexes were S. sagax (16.58%), Euphylax dovii (15.95%), Stenocionops ovata (12%), and P. planipes (11.82%) for females. There were significant differences in the amount and type of prey consumed between types of reproductive season; the species contributing the most to differences between seasons were Anchoa spp. (27.76%), and P. planipes for non-reproductive season (22.67%), and S. sagax (11.08%) for reproductive season. The feeding strategy of the barred sand bass was that of a specialist carnivorous predator that fed mainly on the fish Sardinops sagax during the reproductive season, which supply the dietary nutritional requirements of the lipids HUFA (arachidonic acid, 20:4n-6; eicosapentaenoic acid, 20:5n-3; docosahexaenoic acid, 22:6n-3), nutrients required to achieve reproductive success.

Reproductive management of the ram (Ovis orientalis aries)

Objective: To describe briefly the physiology, the anatomy and the reproductive management of the ram. Design/Methodology/Approach: Review of the anatomy, physiology and general considerations for an adequate reproductive management of the ram. Results: The ram presents a less seasonal reproductive activity than the female and its reproductive behavior is easier to observe. However, it is in the fall, the reproductive season of seasonal sheep, when their behavior is much more complex and complete. It begins with smelling the external genitals of the female, goes through the flehmen response and ends with mating, intromission and ejaculation. It is necessary to consider the anatomical and physiological aspects of the ram and its meticulous management to avoid reproductive failures in the flock. Frequently, the rams are less important for the flock’s handler during the season of reproductive rest. Monitoring their diet and parasite and disease control is necessary to keep them apt for reproduction. The evaluation of the reproductive aptitude of the ram before mating is convenient and can be planned as part of its management; and once mating begins, considering the adequate proportion of rams/females, in addition to monitoring their performance during this event. Study Limitations/Implications: To consider that the ram shows a good capacity for mating, capacity for service, libido, quality of semen, since it is responsible for a proportion of lamb production. Findings/Conclusions: Reproduction in sheep is regulated by the photoperiod, genetic potential, nutritional status, health status and other factors, which are important both in the ram and in the female. Some sheep breeds have potential of prolificacy; a good reproductive management of the ram can influence these factors and increase the reproduction rate in the flocks.

Sheep reproductive management

Objective: To describe some reproductive management programs that allow increasing the productive efficiency of ewes. Design/methodology/approach: Description of the main hormones and their application in sheep reproductive management protocols. The subjects are reviewed based on academic references as well as on their use in sheep reproductive protocols at the Sheep and Goat Reproduction Laboratory of the Colegio de Postgraduados, Mexico. Results: Hormones, socio-sexual strategies, reproductive protocols and techniques are tools that improve the reproductive efficiency of ewes during the reproductive season and seasonal anestrus. Study limitations/implications: The basic techniques of reproductive management and protocols in sheep are mostly available, however, they still have room for improvement, therefore, multiple efforts involving all participants, such as the primary sector, public and private institutions, are required. Findings/conclusions: Reproductive management is an important pillar for animal production; thus its implementation is fundamental to improve the reproductive and productive efficiency of a herd

Evaluation of seminal characteristics of Pelibuey and East Friesian rams at two different times of the year

Objective: To determine the changes in seminal quality of Pelibuey and East Friesian rams during the non-breeding (long days; March-June) and breeding seasons (short days; September-December) at 19° north latitude. Design/methodology/approach: To determine changes in seminal quality over time, seminal parameters of rams, collected with an artificial vagina were evaluated over 32 weeks. An analysis of variance was performed with a completely randomized design in a 2 x 2 factorial arrangement (breed and season). Results: No differences were found within breeds or between breeds in the same season in the evaluated seminal parameters; however, differences were reported between seasons in the live weight parameters, lower in the non-reproductive season, in addition to an increased scrotal circumference and mass motility during the reproductive season. Study limitations/implications: Semen parameters estimation, in field trials, is subjective compared to computerized semen evaluation systems, it is therefore desirable to have extensive experience in semen evaluation at the field level before starting the study. To confirm the results obtained in this study, a new experiment with a larger number of experimental units is suggested. Findings/conclusions: It is concluded that in the environmental and management conditions, where the seminal evaluation took place, no differences were found between breeds, suggesting that the Pelibuey and East Friesian breeds at 19° north latitude do not decrease their seminal parameters during the non-breeding season compared to the breeding season. This suggest that these two sheep breeds are able to reproduce, in such conditions, all year round.

Morphological Characteristics of the Sperm of the Peregrine Falcon (Falco peregrinus) during the Reproductive Season

The morphological characteristics of different sperm cells (normal, abnormal, and immature) in the peregrine falcon during the reproductive season were analysed. We also classified the main sperm defects found in semen. Semen samples were collected from mature peregrine falcons via cloacal massage and stained with Diff-Quik stain. The percentages of normal, abnormal, and immature sperm cells were determined by bright-field optical microscopy. The number of normal spermatozoa were greater at the initial stage and subsequently decreased during the middle and later stages of the reproductive season (p < 0.01). In contrast, the percentage of abnormal spermatozoa increased significantly in the middle and end stages of the reproductive season (p < 0.05), whereas the proportion of immature spermatozoa remained stable during the study. Head defects represented the greatest proportion of morphological abnormalities, followed by the defects in the tail and midpiece regions. A small percentage of multiple defects and cytoplasmic droplets were also observed in the falcon spermatozoa. The findings of this study might be important for the development of future conservation protocols for falcon sperm.

Estrus induction in the non-breeding season is not associated with hydrometra in dairy goats

This study aimed to compare the prevalence of hydrometra (HD) at the end of the reproductive season in goats subjected (HORM and LIGHT) or not (Control-HORM and Control-LIGHT) to estrus induction by either hormonal protocol or light program, respectively, in the non-breeding season. HORM-goats received intravaginal sponges (six days) associated with cloprostenol plus eCG 24 h before sponge removal while LIGHT-goats were submitted to 16 h of light and 8 h of darkness for 60 days. Pregnant goats from both groups gave birth at the early reproductive season and were evaluated by transrectal ultrasound ~45 days after the end of the season. The control goats (Control-HORM and Control-LIGHT) were also examined. There was no difference in the prevalence of HD between goats from HORM (8/31; 25.8%) compared to Control-HORM (4/26; 15.4%), or LIGHT (9/54; 16.7%) compared to Control-LIGHT (7/51; 13.7%), as well as between HORM and LIGHT groups. In conclusion, estrus induction with both hormonal and light protocols is not associated with the development of HD in dairy goats.