Performance Of Rams Research Articles

Influence of Management Systems on Severity of Heat Stress and Reproductive Performance of Rams in the Tropics – A Review

Abstract Sheep are an important source of protein for humans, and recent decades have seen a significant increase in the production of sheep-based products, thus indicating an increase in demand for this commodity. At a time when this sector is growing, sheep are exposed to various challenges. These include climate change, which can cause heat stress in sheep, including rams, which later negatively affects their growth and reproductive performance. Exposure to heat stress results in physiological and reproductive behaviour responses in rams, which could also be used to visually identify the effect of heat stress as it will affect the productivity of livestock. In addition, the year-round hot and humid climate of the tropics is expected to contribute to a higher probability of heat stress occurrences in rams reared in developing countries around the equator. Nevertheless, the adaptability of rams to heat stress varies according to their origin, whereby native breeds tend to adapt better. Despite that, native breeds still can be affected by adverse environmental conditions and rely on thermoregulation mechanisms to mitigate heat stress. This results in numerous negative physiological changes, such as sweating and increased heart rate. This review highlights the effects of heat stress on the physiology, reproductive behaviour and reproductive performance of male sheep. The review also discusses the impact of management systems on heat stress in rams, which affects sheep productivity.

Effects of feeding Pennisetum purpureum silage supplemented with selected farm residues on growth performance and meat quality of west African dwarf rams

Effects of feeding Pennisetum purpureum silage supplemented with selected farm residues on growth performance and meat quality of west African dwarf rams

Numerical and experimental analyses of hydraulic rams

This study explores hydraulic rams, a technology that exploits the effect of water hammer to pump water without the need for external artificial energy. Although first developed in the 18th century, a comprehensive numerical model elucidating the dynamics of each element, including valve manoeuvres, remains absent. Few authors have contributed specific models, often relying on simplistic approaches like rigid water column theory, or the method of characteristics (MOC) for water hammer equations with either instantaneous valve manoeuvre boundary conditions, or depicting the hydraulic ram as a single-node boundary condition. Some use sophisticated computational fluid dyamics (CFD) based models, primarily for optimizing individual components like the waste valve. Addressing this gap, this work introduces a novel comprehensive numerical model detailing full system dynamic – pipes, junctions, and valve behaviour. Analytical validation and experimental verification, using original laboratory-scale data, affirm the model's reliability. This advance improves understanding of hydraulic ram performance and encourages innovative, environmentally sustainable designs.

Enhancing the Performance of Electrochemical RAM (ECRAM) through Modeling Guided Device Engineering

Traditionally, the only ions allowed or welcomed by the microelectronic industry are those that act as fixed dopants. The issue of mobile ions became welcome primarily due to the memristor technology however, thin film transistor technologies benefit from them too. The electrochemical (transistor) random access memory (ECRAM) is emerging as a promising building block for multi-level neuromorphic computing. Using FAB-compatible materials we construct the ECRAM using CuOx as the gate and ions source (Cu+). The morphology of the HfOx gate insulator layer is tuned to render it ion transporting such that it can act as a uniform electrolyte layer. Lastly, the channel material is WOx with tungsten metal as the source/drain contact.While there are several reports of ECRAM devices, the operation mechanisms are not fully known/understood thus withholding progress of this field. Using the Sentaurus device simulator by Synopsis, including the hydrogen diffusion module, we simulate the mixed ionic electronic operation of the device. We have recently reported that by fitting the simulation to the device performance, we could identify the potentiation mechanism (i.e., insulator charging) and the occurrence of copper plating that takes place under high Cu+ ion flux (as in fast charging of Li batteries).[1]In the first part of the talk, we will expand on the chemical-physics details of the ECRAM device mentioned above. Next, we will present a new device architecture where we remove the WOx layer and study the ionic-electronic conduction of a modified HfOx layer. By fine-tuning the stoichiometry of the HfOx layer, it assumes both roles of ionic electrolyte and electronic conducting channel. Following detailed modelling of the measured properties, we introduce AlO2 as an ionic barrier layer at the WOx/HfOx interface to enhance the ionic retention of the HfOx layer. Using the above three device architectures in conjunction with the mixed ionic-electronic device simulation we reveal the role of the two memory mechanisms: a) Electric field-activated ion transport and b) Structure-induced trapping by ion-barrier layers.Reference[1] Nir Tessler, Nayeon Kim, Heebum Kang, Jiyong Woo; Switching mechanisms of CMOS-compatible ECRAM transistors—Electrolyte charging and ion plating. J. Appl. Phys. 21 August 2023; 134 (7): 074501. https://doi.org/10.1063/5.0154153 Figure 1

Intake and growth performance of growing Uda rams fed diets containing different proportions of urea-treated millet husk as a replacement of cowpea husk

A sixty-three-day feeding trial investigated the nutrient intake and growth performance of growing Uda rams fed diets containing different proportions of urea-treated millet husk to replace cowpea husk. Sixteen growing Uda rams with a mean weight of 18 kg and aged 12 – 18 months were used for the study. Animals were balanced for weights and allotted into four dietary treatments with four (4) animals per treatment in a Completely Randomized Design. Urea-treated millet panicle husk proportions of 0:30, 10:20, 20:10, and 30:0 to replace cowpea husk was formulated as a complete diet consisting of wheat bran, cowpea husk, soybeans mill, and salt. The diets were designated as T1, T2, T3 and T4 respectively. The animals were fed the complete diets ad libitum at 1.5% of individual body weight. Data generated were subjected to analysis of variance. Differences in means were compared using Duncan’s Multiple Range Test. The results revealed that animals fed 10% and 20% Millet husk diet were better compared to those placed on 30% millet husk in terms of, dry matter intake, weight gain, and nutrient digestibility. The findings also show that Millet husk could be supplemented in the diets of sheep up to 20% without detrimental effects on the growth performance of Uda rams.

Polymorphism of growth hormone (GH/HaeIII) gene and its association with the performance of merino cross rams

Merino cross sheep (75% Merino × 25% Garut) are introduced by the government of Indonesia for meat production purposes. The present study aimed to determine the polymorphism in the exon 2 region of the growth hormone (GH) gene (422 bp) in Merino cross rams using the PCR-RFLP technique and to analyze its relationship with body weight and body measurements of the rams. A total of 145 rams aged one-year-old with an average body weight of 29.08 ± 7.96 kg from the breeding station in West Java, Indonesia were considered as the experimental animals. It was indicated that a missense mutation of c.55G > A (p.G19S) was detected in the target sequence of the GH gene in Merino cross rams. The PCR-RFLP analysis in the GH gene of Merino cross with HaeIII restriction enzyme (GH/HaeIII) was observed in a moderate category with a polymorphic informative content (PIC) value of 0.22. Therefore, the G allele was more frequent than the A allele (0.85 versus 0.15). Furthermore, the genotype AA was not present among the sheep that were part of the study. However, the polymorphism of p.G19S was found to have no significant association with birth weight and body measurements in one-year-old Merino cross sheep. However, the GH/HaeIII gene in Merino cross rams exhibited polymorphism, primarily with two genotypes: GG (wildtype) and GA (carrier). The G allele was identified as the dominant allele in the ovine GH gene, occurring with a frequency of 0.85. Importantly, the polymorphism of the GH/HaeIII gene was significantly linked to birth weight and chest depth in one-year-old Merino cross rams. These findings provide preliminary insights that could potentially aid in the early stages of molecular selection for Indonesian Merino cross sheep.

Study on the correlation of supplementation with L-citrulline on the gastrointestinal flora and semen antifreeze performance of ram.

Cryopreservation of semen can give full play to the reproductive advantages of male animals. However, in actual production, due to the poor frost resistance of sheep semen and the low conception rate, the promotion of sheep frozen semen is greatly hindered. Therefore, it is urgent to improve the frost resistance of semen to improve the quality of frozen semen. At present, most studies on improving the quality of frozen semen are based on the improvement of semen dilutions, and few studies on improving the freezing resistance of ram semen by feeding functional amino acids. Therefore, 24 Turpan black rams were divided into high antifreeze group (HF) and a low antifreeze group (LF) Each of these groups was further randomly divided into control and experimental subgroups. The control subgroup was fed a basal diet, while the experimental subgroup received an additional 12 g/d of L-Cit supplementation based on the control group for a duration of 90 days. The results showed that Following L-Cit supplementation, the experimental group demonstrated significantly elevated sperm density and VSL (Velocity of straight line), T-AOC, GSH-Px, and NO levels in fresh semen compared to the control group (P < 0.01). After thawing, the experimental group exhibited significantly higher levels of T-AOC, GSH-Px, and NO compared to the control group (P < 0.01). Additionally, the HFT group, after thawing frozen semen, displayed significantly higher HK1 protein expression compared to the control group. The number of spermatogonia, spermatocytes, and sperm cells in the HFT group was significantly higher than that in the HFC group. Moreover, 16S rRNA sequence analysis showed that Candidatus_Saccharimonas, Staphylococcus, Weissella, succinivbrionaceae_UcG_002, and Quinella were significantly enriched in the rumen of the HFT group, while Ureaplasma was significantly enriched in the HFC group. In the duodenum, Clostridiales_bacterium_Firm_14, Butyrivibrio, and Prevotellaceae_NK3831_group were significantly enriched in the HFT group, whereas Desulfovibrio and Quinella were significantly enriched in the HFC group. Under the conditions employed in this study, L-Cit supplementation was found to enhance the intestinal flora composition in rams, thereby improving semen quality, enhancing the antifreeze performance of semen, and promoting the development of testicular spermatogenic cells.

Mathematical model of an antenna-waveguide path with signal separation by polarization – frequency

Background. The need to create antenna-waveguide paths for multi-band reflector antennas of satellite communication systems requires the use of various methods for selecting the structure, determining and optimizing the parameters of antenna-waveguide paths.&#x0D; Aim. Development of a mathematical model of antenna-waveguide paths of multi-band reflector antennas, built on the basis of the «polarization separation – frequency separation» method with the implementation of the auto-tracking function.&#x0D; Methods. A mathematical model of antenna-waveguide paths of multi-band reflector antennas, built on the basis of the «polarization separation – frequency separation» method, allows us to determine the main characteristics of antenna-waveguide paths and incoming devices with an auto-tracking function.&#x0D; Results. The main elements of the mathematical model of multi-band antenna-waveguide paths built on the basis of the «polarization separation – frequency separation» method are determined.&#x0D; Conclusion. A mathematical model has been proposed that makes it possible to reduce the requirements for the computing tools used when developing antenna-waveguide paths in terms of RAM capacity and performance. The ability to analyze and determine the characteristics of antenna-waveguide paths using a mathematical model has been implemented. The stages of determining the parameters of antenna-waveguide paths are presented, based on the developed mathematical model of the corresponding design option, as well as theoretical and experimental data confirming the correctness of the model of antenna-waveguide paths.

Systematic review of hormonal strategies to improve fertility in rams.

Reviewing the current state of knowledge on reproductive performance and productive traits in rams has many advantages. First, the compilation of this information will serve as a literature resource for scientists conducting research around the world and will contribute to the understanding of the data collected and interpreted by researchers on the different hormonal strategies used to improve reproductive performance in rams. Second, it will allow scientists to identify current knowledge gaps and set future research priorities in ram reproduction. Rams play an important role in the global flock economy, but their reproductive analysis has been limited in the use of hormonal technologies to increase the productivity of sheep flocks. In this review, we cite the most important works on six hormones that, in one way or another, modify the hypothalamus-pituitary-gonadal axis, at different doses, in and out of the reproductive season, breeds, application methods, among other factors. The overall aim is to increase the reproductive efficiency of rams in different scenarios and, in some cases, of other species due to the lack of limited information on rams.

Impact of seaweed on growth performance, sperm quality and testicular histomorphology of ram

Sperm quality is critical for male fertility, which is largely dependent on testicular development; however, nutrition is critical for optimal growth, gonadal development, and reproductive functions. This study was aimed to investigate the effects of Gracilaria parvispora, a red seaweed on growth performance, testicular physiology, and semen quality in ram. Fifteen indigenous rams, weighing 10-11 kg and aged 12-13 months, were randomly allocated into three groups. One group was considered as control and supplied with German grass and concentrate mixture (control diet). The other two groups were provided with control diet plus seaweed mixture either at 7 g/d or 14 g/d. The starting body weight, scrotal circumferences and semen quality of rams were similar for all groups. However, post-treatment, both the seaweed-treated groups showed significantly higher body weight, total weight gain, daily weight gain, and increased scrotal circumference and testicular dimensions, compared to control group. Moreover, the semen parameters, including sperm concentration, live sperm percentage, mass motility and progressive motility were observed to be significantly increased, while decreasing abnormal sperm percentage in the seaweed-treated group. Furthermore, DPPH and ABTS scavenging abilities, and in vitro fertilization rate were significantly increased in seaweed treated groups. Additionally, the testicular histology of seaweed treated groups revealed a thinner tunica albuginea with expanded seminiferous tubules containing higher number of spermatogenic cells inside. These findings suggested that seaweed G. parvispora could be a valuable dietary supplement for enhancing the growth and reproductive performance of ram.

Stochastic Reliability Modelling of Hr/M/1/N Queueing System with Working and Working-Breakdown States

Abstract: This study models the reliability, availability, and maintainability of a finite capacity Hr /M/1/N phase queueing system in working and working-breakdown states. The arrival times are distributed according to a Hyperexponential distribution with rparallel phases, whereas the service times are distributed according to an exponential distribution. The differential-difference equations for the transient states are derived from the state-transition diagram for different environmental states, as well as failure and recovery states. For the particular situation of N=4, these governing equations are solved numerically. Sensitivity Analysis was used to investigate RAM performance measures for various parametric variables.

Evaluation of the effect of melatonin implantation in rams and eCG dose in ewes synchronized by a CIDR-eCG protocol on reproductive performance of Lacaune sheep breed during non-breeding season

Sustainable production of milk is favorable in dairy sheep industry, which necessitates year-round reproduction of rams and ewes even during non-breeding season. Hence, protocols facilitating reproduction of rams and ewes during non-breeding season are of importance for this purpose. Therefore, the present study was conducted to investigate the effect of melatonin implantation in rams and administration of 400 IU eCG (E400) versus 300 IU eCG (E300) in ewes on reproductive performance of Lacaune sheep breed during non-breeding season. Rams were allocated to two groups including untreated (control, CON; n = 36) and melatonin-treated (MEL; n = 37). A subset of rams from CON (n = 7) and MEL (n = 7) groups were used for assessment of scrotal circumference, kinematic and functional characteristics of sperm, total antioxidant capacity (TAC) of semen and circulating testosterone on Days 0 (the beginning of study) and 60 (60 days after melatonin implantation). Further, the study had a 2 × 2 factorial design with four experimental groups including 1) ewes treated with E300 and introduced to CON rams (E300CON; n = 17 rams and 172 ewes), 2) ewes treated with E300 and introduced to MEL rams (E300MEL; n = 18 rams and 177 ewes), 3) ewes treated with E400 and introduced to CON rams (E400CON; n = 19 rams and 192 ewes), and ewes treated with E400 and introduced to MEL rams (E400MEL; n = 19 rams and 190 ewes). Melatonin implantation improved scrotal circumference, concentration, progressive motility, velocity, mitochondrial membrane potential and viability of sperm, TAC of semen, concentration of testosterone and fertility of rams (P < 0.05). Besides, E400 compared with E300 enhanced synchronization of estrus and fertility in ewes (P < 0.05). In conclusion, melatonin implantation promoted reproductive performance in Lacaune rams, and increase in dose of eCG improved reproductive performance in Lacaune ewes.

ANALISIS PERBANDINGAN PERFORMA VIRTUALISASI SERVER MENGGUNAKAN VMWARE ESXI, ORACLE VIRTUAL BOX, VMWARE WORKSTATION 16 DAN PROXMOX

In the era of advancing digitization, server infrastructure plays a key role in the development of applications and web services. To effectively and efficiently manage and develop virtualized servers, server virtualization techniques can be employed. There are several virtualization platforms available, such as VMware Workstation 16, VMware vSphere (ESXi), Oracle VirtualBox, and Proxmox, each with their own strengths and weaknesses. The objective of this research is to analyze the performance of these four virtualization platforms in developing and managing virtualized servers used for web services, taking into consideration response time, throughput, CPU performance, storage performance, and RAM performance. Experimental methods were used to test these four platforms and measure CPU performance, RAM performance, disk performance, throughput, and response time using Moodle benchmark. The data was then analyzed to draw conclusions about the performance of each platform. The research results show that VMware vSphere ESXi and Proxmox have better CPU performance and response time when handling multiple virtual machines, and are more efficient in disk and memory usage compared to VMware Workstation 16 and Oracle VirtualBox. Significant differences in data transfer speed were found among the four platforms. Overall, VMware vSphere ESXi and Proxmox can be considered better choices for running web servers.

Optimization of Railway Infrastructure Asset – A Review

Railway infrastructure assets are key components in the railway transportation system. Optimal asset management is essential to improve the efficiency and productivity of the railway system, as well as help prevent unnecessary costs in the asset life cycle. Reliability, Availability, Maintainability, and Safety (RAMS) and Life Cycle Cost (LCC) methods can be used in managing railway infrastructure assets. RAMS is a method used to assess the performance of high-complexity systems such as rail infrastructure systems. In contrast, LCC is used to evaluate the overall cost of a system or asset over the life cycle. Integrating RAMS and LCC concepts can help plan railways' design, operation, and maintenance. This integration is very flexible as it can be done from the life cycle's design, operation, and maintenance stages. Research shows that using the integration of RAMS and LCC can lead to better strategic decisions in the life cycle of a railway. In selecting assets to support design and maintenance, for example, there are two high-speed rail double-track alternatives of ballasted and ballastless track, with results showing that ballastless track has higher RAMS performance and lower maintenance cost but higher construction costs, so ballasted track solutions are preferred for short-term construction and the ballastless track is preferred for long-term.

Effect of dietary supplementation of duckweed on growth performance, carcass and non-carcass traits of horro rams fed on a commercial-based diet

The study was aimed at evaluating growth performance, carcass, and non-carcass traits of Horro rams fed on commercial feed (CO) supplemented with different proportions of duckweed (DW). For the study, twenty-four yearling Horro rams initially weighing on average 17.73 ± 0.30 kg were used with a 15-day adaptation period (none-study period) and a 90-day study period. Each animal was randomly assigned to three treatments; T1 (100% CO), T2 (25% DW + 75% CO), and T3 (50% DW + 50% CO) with two replications each containing four animals. All diets were isocaloric and isonitrogenous and formulated according to the nutrient requirements of sheep. The data were analyzed using SAS. Results indicated that dry matter intake in T3 (914.37 g. d-1) was higher (P < 0.001) than in T1 (849.12 g. d-1) and T2 (870.50 g. d-1). Average daily body weight gain in T3 (77 g. d-1) was higher (P < 0.001) than in T1 (48.60 g. d-1) and T2 (58.50 g. d-1). Feed conversion efficiency was higher (P < 0.001) for T3 (0.08) followed by T2 (0.07) and T1 (0.05). Final body weight (24.56 kg), empty body weight (20.40 kg), hot carcass weight (10.27 kg), dressing percentage (42.01) and rib-eye muscle area (9.11 cm2) were higher (P < 0.001) for T3 than for others. Therefore, increasing the inclusion level of supplementary duckweed up to 50% improves growth performance, carcass quality, and yield of Horro ram.

PERFORMANCE AND HAEMATOLOGICAL INDICES OF BALAMI RAMS FED CATTLE URINE-ENSILED SORGHUM STOVER AS SOURCE OF NON-PROTEIN NITROGEN

A 90-days feeding trial was conducted to evaluate the effect of replacing fertilizer grade urea with cattle urine in sorghum stover silage on the performance and haematological indices of Balami rams. Five diets were formulated. Diet 1 (control) contained sorghum stover ensiled with fertilizer grade urea (FGU) while diets 2, 3, 4 and 5 had 25, 50, 75 and 100% levels of cattle urine as replacement for FGU. Twenty (20) rams of the Balami breed were allotted to the five diets in replicates of four in a completely randomized design. Data on daily feed intake, weight gain and haematological indices were collected Results showed no significant influence of cattle urine on daily feed intake. However, Daily weight gain was significantly (P&lt;0.05) higher on T5 (128.11 g) and T4 (124.08 g) which were the same, than on other diets which also did not differ (101.67 – 103.65 g). Similarly, Rams fed T5 (34.53 kg) had higher (P&lt;0.05) final weight than those on other diets which were the same (30.30 – 31.93 kg). Feed conversion ratio was significantly (P&lt;0.05) better on T5 (5.74) and T4 (5.88) compared to T1 (7.19), T2 (7.13) and T3 (7.06) which were poorer. All haematological indices did not significantly differ among diets. It was therefore concluded that cattle urine can completely replace fertilizer grade urea as silage additive in sorghum stover and as non-protein nitrogen source in balami rams diets.

Evaluation of the Effects of Melatonin Implants on Testicular and Spermatic Parameters of Rams Raised in Station in the Niayes Zone in Senegal

The intensification of livestock production in response to the growing demand for animal products is increasingly creating new challenges in terms of control of livestock management and feeding, and especially reproduction. Also, ewes are often considered responsible for infertility problems in a sheep flock, as the reproductive capacity of rams is often taken for granted. However, it is important to have genetically superior males to improve the overall fertility of the herd. And, one way to control the sexual performance of rams and improve their fertilizing capacity, is to have them undergo melatonin treatment. The objective of this study was to evaluate the effects of the use of melatonin implants on testicular and spermatic parameters of rams raised in stations in the Niayes area of Senegal. The experimental herd consisted of 6 rams of well-known body characteristics which were followed for 2 months during which testicular measurements were carried out at the beginning and semen was collected by electroejaculation every 2 weeks. After a break of 2 weeks, the same rams are implanted with melatonin (MELOVINE ®) at a rate of 3 implants/ram, i.e. a dose of 54 mg of melatonin per ram, and the same measurements and semen collections are again carried out for 2 months. Data on antero-posterior testicular diameter, testicular weight, scrotal circumference, and semen analysis (volume, color, appearance, mass and individual motility, concentration, morphology) recorded and processed with Excel were exported to the SPSS software where they were subjected to descriptive statistical analysis and independent sample comparison testing. The results showed that melatonin treatment significantly reduced weight (555±155 g vs. 396±128 g) and antero-posterior diameter (23.42±2.0 cm vs. 20.10±2.26 cm). However, it induced improvements in ejaculate volume, color, and appearance, sperm production, and morphological abnormality rate, and, most significantly, sperm motility (2.1±1.5 vs. 3.3±1.2) and survival rate (54±34% vs. 80±31%) of spermatozoa. Melatonin has therefore improved the sperm characteristics of rams, and is an interesting reproductive management tool for improving the productivity of sheep farms. It can be recommended for use in artificial insemination centres in order to improve the characteristics of the semen doses produced.

155 Rams Enrolled in the National Sheep Improvement Program have Improved Performance and Value in Ram Test Program

Abstract Genetic evaluation programs can provide valuable selection tools for sheep breeders. However, industry acceptance and utilization of these tools is still limited. The objective here was to evaluate the performance and value of rams enrolled in the National Sheep Improvement Program (NSIP) compared with those not enrolled during a ram test program. Rams (Katahdin = 16, Texel = 3) were delivered to the Southwest Virginia Agricultural Research and Extension Center Ram Test on May 31. Rams were dewormed and rested for two weeks. On June 21, rams were given Haemonchus contortus L3 larvae adjusted for body weight (average = 5000 L3). FAMACHA scores and fecal egg counts (FEC) were monitored every two weeks until August 30. Rams were dewormed based on FAMACHA ≥ 3. The top 50% of rams, excluding any dewormed rams, based on the sale index [Sale Index = 0.50*(0.33*average daily gain ratio + 0.67*weight per day of age ratio) + 0.50*logFEC ratio] were sold at auction as breeding stock. Rams were classified as NSIP if enrolled. Statistical analyses were performed using SAS (SAS Institute, Cary, NC). Of the19 rams on test, 52% were NSIP. Thirteen rams required deworming during the test (38% of these were NSIP rams). Average sale index of NSIP rams tended to be greater than that of non-NSIP rams (101.4 vs. 98.3, P = 0.06). Of rams with sale index ≥ 100 (top 50%), a greater percentage of these rams were NSIP vs. non-NSIP (61% vs. 39%, respectively; P &amp;lt; 0.05). When NSIP status was evaluated for the top 20% of rams (sale index ≥07), a greater percentage of these rams were also NSIP vs. non-NSIP (78% vs. 22%, respectively; P &amp;lt; 0.01). Rams (n = 57) were sold on September 23 with an average sale price of $1,482. Rams enrolled in NSIP commanded greater prices than those not enrolled ($1,659 vs. $1,222, P &amp;lt; 0.05). When sale price was regressed on sale index for NSIP and non-NSIP rams, R2 for NSIP rams was 0.19 compared with the R2 for non-NSIP rams of 0.76. Given the weaker relationship between price and sale index for NSIP rams, estimated breeding values (EBVs) were evaluated. NSIP rams with EBVs reported for post-weaning weight, post-weaning FEC, and Maternal Hair Index sold for greater prices than those rams missing one or all of these EBVs ($1,837 vs. $971, respectively; P &amp;lt; 0.05). In summary, NSIP rams had greater performance (as indicated by sale index) and value compared with non-NSIP rams. For rams enrolled in NSIP, sale index was a poor predictor of value indicating buyers may be considering other factors besides sale index, such as EBVs, when purchasing NSIP rams.

008 Administration of C6 – a kisspeptin analogue – to improve the reproductive performance in rams during the non-breeding season

008 Administration of C6 – a kisspeptin analogue – to improve the reproductive performance in rams during the non-breeding season

Reproductive performance of hair ewes and rams implanted with melatonin previous to the anestrus season in northwest Mexico.

Ovine reproductive behavior depends on annual photoperiodic cycle and its impact on endogenous melatonin secretion. In this regard, exogenous melatonin administration previous to the physiological anestrus period could modify the reproductive performance of sheep in the northwest of Mexico. Two independent studies were performed to evaluate such hypothesis in hair sheep implanted with melatonin prior to the anestrus season in latitudes 24° and 25° of Mexico. Study 1 involved 15 rams assigned to one of three treatments receiving 0mg (n=5), 18mg (n=5), or 36mg (n=5) of melatonin subcutaneously. Study variables were measured monthly since implantation (d0) and included testosterone concentration, scrotal circumference, mass motility, individual motility, and sperm concentration. Study 2 included 50 ewes assigned to one of two treatments receiving 0mg (n=25) or 18mg (n=25) of melatonin subcutaneously. In ewes, progesterone concentration and the frequency of females in anestrus were measured during the implantation (-30d), as well as at the beginning (0d) and at the end (45d) of the mating period, while pregnancy rate was determined by ultrasonography 45d after. Continuous variables were analyzed using a mixed effects model considering treatment, time, and the treatment by time interaction as fixed effects. Animal nested within treatment was the random effect. Binary variables were analyzed using the chi-square test. In males, melatonin improved testosterone and sperm concentrations (P<0.05), while in females, a 28% higher pregnancy rate was observed in implanted ewes (P<0.05). Therefore, melatonin enhanced reproductive parameters in both sexes and its exogenous administration previous to the anestrus season in northwest Mexico could be more effective in rams.