Prolificacy Rate Research Articles

Genome-wide association study and pathway analysis identify NTRK2 as a novel candidate gene for litter size in sheep.

Litter size is one of the most important economic traits in sheep. Identification of gene variants that are associated with the prolificacy rate is an important step in breeding program success and profitability of the farm. So, to identify genetic mechanisms underlying the variation in litter size in Iranian Baluchi sheep, a two-step genome-wide association study (GWAS) was performed. GWAS was conducted using genotype data from 91 Baluchi sheep. Estimated breeding values (EBVs) for litter size calculated for 3848 ewes and then used as the response variable. Besides, a pathway analysis using GO and KEGG databases were applied as a complementary approach. A total of three single nucleotide polymorphisms (SNPs) associated with litter size were identified, one each on OAR2, OAR10, and OAR25. The SNP on OAR2 is located within a novel putative candidate gene, Neurotrophic receptor tyrosine kinase 2. This gene product works as a receptor which is essential for follicular assembly, early follicular growth, and oocyte survival. The SNP on OAR25 is located within RAB4A which is involved in blood vessel formation and proliferation through angiogenesis. The SNP on OAR10 was not associated with any gene in the 1Mb span. Moreover, gene-set analysis using the KEGG database identified several pathways, such as Ovarian steroidogenesis, Steroid hormone biosynthesis, Calcium signaling pathway, and Chemokine signaling. Also, pathway analysis using the GO database revealed several functional terms, such as cellular carbohydrate metabolic, biological adhesion, cell adhesion, cell junction, and cell-cell adherens junction, among others. This is the first study that reports the NTRK2 gene affecting litter size in sheep and our study of this gene functions showed that this gene could be a good candidate for further analysis.

Application of laparoscopic artificial insemination in conventional Lacaune sheep farm using frozen-thawed semen

The complex anatomical structure of the ewe reproductive tract accompanied with low quality of frozen ram semen for artificial insemination, resulted in a challenge with regard to using superior genotypes for reproductive ovine performance. Hence, improved genetics in ovine management has not been efficiently and widely used especially in undeveloped countries. Therefore, intrauterine semen deposition by laparoscopic insemination should be adopted in the current sheep production systems. Thus, this study aimed to assess the pregnancy rate and lambing rate of ewe inseminated by laparoscopic insemination techniques using frozen-thawed semen. The research used imported frozen semen from two rams of the Lacaune breed. Ewes were grouped according to age in years (1, 2 and 4). Before insemination, the semen was examined microscopically for its motility and viability and thereafter the laparoscopic artificial insemination technique was performed to 19 Lacaune breed ewes using frozen-thawed semen. The overall pregnancy and prolificacy rates were 31.57% and 42.10% respectively. Out of 2 ewes in the 1-year age group that were inseminated, only 1 ewe lambed representing 50%. However, from 16 ewes inseminated of four-year age group, 5 ewes lambed representing 31.25%. Significant difference based on age group was not evaluated due disproportionate of the data, (such that the data included 2 ewes in one-year-old age, 1 ewe in 2-year-old age and 16 ewes in 4-year-old age). Based on the ram semen, 33.33% and 30% of the inseminated ewes were pregnant from ram A and ram B semen respectively. However, in the case of prolificacy rate, 44.44% and 40 % of the ewes lambed from using semen of ram A and B, respectively. There was no significant difference (p>0.05) in pregnancy and prolificacy rates based on semen from the two rams. In conclusion, in this research study, ram semen had no significant effect on pregnancy and prolificacy rates using laparoscopic AI on Lacaune sheep. This could be due to the fact that the rams had very good quality semen. Evaluation of ram semen, accompanied with appropriate ewe selection based on age and rightful deposition of semen could lead to better and more consistent results. Overall this could contribute to the successful application of laparoscopic artificial insemination in Lacaune sheep production systems for enhanced productivity.

Effects of immunization against inhibin α-subunit on ovarian structures, pregnancy rate, embryonic and fetal losses, and prolificacy rate in goats where estrus was induced during the non-breeding season

The objectives of the study were to determine the dose-dependent effects of active immunization against inhibin α-subunit (AIINHA) on ovarian dynamics, concentrations of progesterone (P4), pregnancy rate (PR), embryonic and fetal losses (EFL), and prolificacy during the non-breeding season when there was imposing of a progestin-based treatment regimen to induce estrus in Beetal goats. Goats (n = 30) were randomly assigned into following groups: 1) saline (G-CON-0 mg; n = 10), 2) small dose (G-AIINHA-0.5 mg; n = 10), and 3) large dose (G-AIINHA-1 mg; n = 10). The primary administration of inhibin immunogen was administered at Day -48, followed by another administration at Day -20, and subsequently there was induction of estrus using a progestin based treatment regimen that included a single administration of progestin-containing sponge and PGF2α at Day -8. The sponge was removed, and GnRH was administered at Day -3 followed by breeding (Day 0) at standing estrus. Results indicated mean diameter of the follicles, size of pre-ovulatory follicles and corpora lutea, and post-breeding P4 concentrations were greater (P < 0.05) in the goat does of the G-AIINHA-0.5 than G-CON-0 group. The PR, and EFL, however, did not differ (P> 0.05) among groups, whereas prolificacy rate was greater (P = 0.04) in goat does of the G-AIINHA-0.5 than G-CON-0 groups. The data from this study indicate G-AIINHA-0.5 is the recommended dose of inhibin immunogen to enhance the reproductive performance during non-breeding season in Beetal goats when estrus is induced using a progestin-based treatment regimen.

P.416 What's between altered sensory modulation, depression and reduced quality of life in stroke survivors?

The addition of aminopeptidase inhibitors (AMIs) to rabbit semen extenders could be a solution to decrease the hormone degradation (GnRH) by the aminopeptidases existing in the seminal plasma. Therefore, the quantity of GnRH needed to induce ovulation in doe would be comparable with the amount administered intramuscularly (i.m.). This study was conducted to evaluate the effects of two AMIs (bestatin and EDTA) on rabbit semen quality parameters, β nerve growth factor (β-NGF) degradation and reproductive performance after artificial insemination. Results showed that seminal quality was not affected by the incubation with AMIs; the values of motility, acrosome integrity and sperm viability were not significantly different between the AMIs and the control groups (positive i.m. and negative intravaginally without AMIs). In addition, the aminopeptidase activity of seminal plasma was inhibited in a 55.5% by the AMIs as well as β-NGF degradation. On the other hand, regarding the effect of AMIs on reproductive performance, our results showed that the presence of bestatin and EDTA did neither affect fertility (85.3 vs. 88.6%), nor the prolificacy rate (10.12 vs. 10.51 kits per delivery), comparing AMIs group to positive control group, respectively. We conclude that the addition of specific AMIs in the rabbit semen extender has no effect on reproductive performance. Therefore, due to the fact that AMIs inhibit part of the aminopeptidase activity that degrades the GnRH analogue and β−NGF, they could be used to develop new extenders with less hormone concentration.

Polymorphism of fecundity genes, BMPR1B, BMP15 and GDF9, in tropical goat breeds of Kerala

Goat rearing practices in Kerala is mainly centred on two of its native goat breeds, Attappady Black and Malabari. Malabari goats are highly prolific and commonly give birth to two to four kids per kidding, while Attappady Black breed is less prolific; they produce only one or hardly two kids per kidding and multiple ovulation is very rare or nil. Eleven point mutations in the three prolificacy genes, BMPR1B, GDF9 and BMP15, have been identified for making changes in the prolificacy rate of sheep by affecting follicular development and ovulation rate. During the course of this study, we aimed to find out whether any of these gene mutations were responsible for prolificacy difference in Attappady Black and Malabari goats. Test animal selection was done based on their prolificacy rate. Blood samples from individual animals were collected; genomic DNA was extracted and SNP specific Tetra- Primer- ARMS PCR and touch down PCR amplifications were performed to detect any specific mutation in the target genes. All the tested animals, irrespective of breeds were found to carry the heterozygous genotype ‘AG’ for the BMPR1B gene. In the case of BMP15 and GDF9, none of the specific mutations were detected and all the animals were carrying only the wild genotype. Heterozygous genotype for BMPR1B, sheep fecundity gene mutation, appeared to have no significant effect on prolificacy rate as the same genotype was found in both the lowly and highly prolific breeds, Attappady Black and Malabari.

Addition of eCG to a 14 d prostaglandin treatment regimen in sheep FTAI programs

In the present study, there was evaluation of the alternative of adding eCG as part of a long-interval prostaglandin-F2α (PG) treatment on the reproductive efficiency of Merino sheep during the breeding season. A total of 210 ewes and 182 ewe lambs were randomly assigned to three experimental groups to induce the timing of estrus among ewes in a: Long-interval PG, group being synchronized using two doses of PG 14 days apart; Long-interval PG + eCG group being synchronized using the same treatment regimen as Group PG with the addition of 200 IU eCG to the regimen, administered concomitantly with the second PG administration; and MAP + eCG group being synchronized with intravaginal progestin sponges for 14 days plus 200 IU eCG, administered at the time of sponge removal. The percentage pregnancy rate in ewes of the MAP + eCG group was greater than the ewes of the Long-interval PG and Long-interval PG + eCG groups (76.4 % compared with 52.0 % and 62.5 %, respectively; P < 0.05). The prolificacy rate was greater in the ewes of the Long-interval PG+eCG group compared with the other groups (114 % compared with 100 % and 103 %, respectively; P < 0.05). When considering the fecundity rate, ewes of the Long-interval PG+eCG and MAP+eCG groups had greater values than ewes of the Long-interval PG group (71.2 % and 78.8 % compared with 52.0 %, respectively; P < 0.05). The Long-interval PG+eCG is an alternative to the conventional progestin sponge plus eCG treatment regimen with there being a greater fecundity rate when this regimen is used compared with the Long-term PG and similar to MAP-eCG treatment regimens.

Organic breeding in Sarda ewes: Utilization of the ram effect in an artificial insemination program

The current study assesses the ram effect as an alternative to conventional hormonal treatment for estrus synchronization prior to artificial insemination. Two groups of 50 anoestrus Sarda ewes were induced to ovulate with adult rams (RE group) or synchronized using intravaginal sponges impregnated with progestogen and equine chorionic gonadotropin (eCG) (PRO group). Ewes in the RE group were isolated from rams for 6 weeks. After the isolation period, 5 vasectomized rams were introduced into the flock at a ratio of 1 ram/10 females (day 0) to induce estrus and ovulation. Ewes in both experimental groups were inseminated via the cervical route with fresh semen (400 million spermatozoa/0.25 ml) 24 h after the onset of estrus (day 15–24). The pregnancy rate, assessed by ultrasound 35 days after insemination, was 48.9% (24/49) and 43.47% (22/50) for sheep in RE and PRO groups respectively. Lambing rates were identical to pregnancy rates in both groups, while the prolificacy rate was 120% (59/49) and 130% (65/50) in RE and PRO groups respectively. No significant differences were found between the 2 groups. The data supports the conclusion that the ram effect can be used successfully to synchronize estrus in organic farming operations.

Evaluation économique des aulacodes d’élevage engraissés avec trois niveaux de compléments alimentaires dans la production du kilogramme de viande à Grand-Lahou, Côte d’Ivoire (Afrique de l’Ouest)

L’objectif de cette étude est de faire l’évaluation économique des aulacodes d’élevage engraissés avec trois niveaux de compléments alimentaires dans la production du kilogramme de viande Grand-Lahou, Côte d’Ivoire. Le dispositif expérimental était composé d’un bloc aléatoire simple à trois traitements, de rations alimentaires à trois répétitions composées de trois lots de cinq à dix aulacodes chacun. Les lots des aulacodes testés sont répartis en 2 groupes de 3 lots chacun suivant leurs stades physiologiques (en croissance, en engraissement et en entretien). Les trois niveaux de substitution du fourrage vert par une ration complémentaire énergétique dans l’alimentation des aulacodes d’élevage sont composés de : les rations 75 % de fourrages et 25 % de compléments alimentaires (ration T25), 50 % de fourrages et 50 % de compléments alimentaires (ration T50), et 85 % de fourrages et 15 % de compléments alimentaires (ration T15). L’analyse technico-économique est réalisée avec 60 aulacodes en croissance (AC) âgés de 28 jours, 60 aulacodes en engraissement (AEng) âgé de 140 jours et 45 aulacodes reproducteurs en entretien (AEnt) âgés de plus 224 jours dont 36 aulacodines (femelles) et neuf aulacodins (mâles). Les résultats de cette étude ont montré que les meilleures performances de reproduction statistiquement significatives (P

Relationship of some metabolic and hormonal compounds in the blood with the productive and reproductive performance in local Awassi ewes

The study was conducted at AL-Fayhaa station in Jabila province (50 km North of Babil) and laboratories of the Department of Animal production techniques for the period from February to June to show the relationship between some metabolic and hormonal compounds in the blood with production and reproductive performance in local awassi ewes. Data were collected from 50 milking ewes 2-5 years old from 220 records of daily milk production for fertility percentage and prolificacy rate. The results showed that the regression coefficient of daily milk production on total protein (dl) and their coefficient reach to 0.0057 kg.mg-1 and prolactin hormone (ml) were positive and highly significant (P&lt;0.01) and their coefficient reach to 0.019 kg.ng-1 and on glucose concentration (dl) were negative and highly significant (P&lt;0.01) and their coefficient reach to - 0.028 kg.mg-1 and on total cholesterol concentration (dl) were negative and significant (P&lt;0.05) and their coefficient reach to - 0.0053 kg.mg-1. The regression coefficient of fertility percentage on follicle stimulation hormone was observed positive and highly significant (P&lt;0.01) and on triglycerides concentration were positive and significant (P&lt;0.05) . the result also showed that the regression coefficient of prolificacy rate on glucose and total protein concentrations were negative and highly significant (P&lt;0.01) . the correlation coefficient between metabolic and hormone compounds in the blood with production and reproductive performance for ewes were supported to the regression coefficient of same traits .we conclude from this study the possibility of using metabolic and hormonal compounds in rapid selection programs to improve head of ewes .

Reproduction and Growth Performance of the Algerian Tazegzawt Sheep Breed

Three zootechnical criteria: fertility, prolificacy and fecundity were used to evaluate reproductive performance of 23 and 27 multiparous Tazegzawt ewes in experimental station INRAA of Bejaia during autumn mating in 2013 and 2014. A total of 52 lambs were subject to measure the average daily gain at different ages (0, 10, 30, 70, 90 and 180 days) in spring of 2013 and 2014. Some non-genetic factors (sex and type of birth of lambs) were used to study their influencing in dairy production. The results indicated that, the fertility rate was 84.22% and the prolificacy rate was higher than 150%. Fecundity rate seemed interesting in Tazegzawt breed (an average more than 126%). The mean bodyweight (W) at birth was 4.72±0.92kg; 7.22±1.27kg at 10 days, 12.17±2.18kgat 30 days, 21.63±3.02kg at 70 days and 25.80±3.69kg at 90 days of age, the Average Daily Gain (ADGs) estimates for weight at 10 days (ADGs0-10) was 247.48±72.45g/d and decreases with age to reach 208.64±86.20g/d in ADGs70-90. In addition, the highest positive significant correlation (r=0.92, p&lt;0.01) was observed between W30 and ADGs0-30.The growth rate was not affected by sex. However; the influence of birth type on growth performances of lambs during the 30 days showed a superiority of singles over twins (p&lt;0.05). It seems that Tazegzawt sheep is one of the most prolific local breed, it shows a good growth potential. This breed has very promising potentialities that can be exploited to improve mutton meat production in Algeria.

First reproductive and productive results on Ribatejano pig

This trail aimed to study the effect of crossbreeding between Alentejano (AL) and Bisaro (BI) swine breeds (Ribatejano pig) on some reproductive and productive traits. Nine AL gilts and sows and six BI gilts were crossed with BI and AL boars, respectively. Mating and farrowing dates, and litter size at farrowing and 28d were registered. The pregnancy length was shorter on AL sows (111±0.4d vs 113.7±0.5d; P=0.002). The BI gilts presented higher prolificacy rate than AL on both total born (11.0±1.0 vs 6.7±0.8; P=0.004) and born alive piglets (10.0±1.0 vs 6.7±0.8; P=0.026). The mortality rate was similar in both genotypes (P=0.255) being on average 12%. At 28d after farrowing the litter size remained higher in BI sows (8.5±0.8 vs 6.1±0.6; P= 0.032). A subset of each genotype (4 gilts) was supervised during farrowing and lactation (until 28d) and piglets were weighed at birth, 24h and 28d of life. Farrowing length was not significantly different (P=0.253) between genotypes, averaging 97±22 min. When compared to ALBI (ALxBI) piglets, the BIAL (BIxAL) piglets were heavier at birth (1402±46g vs 1209±36g; P=0.002). Colostrum intake of piglets per kg of birth weight on the first 24h of life was similar between genotypes (P=0.735) being 289±15g for ALBI and 281±19g for BIAL piglets. The growth rate of piglets from birth to 28d and piglet weight at 28d were not different between genotypes (P=0.161 and P=0.091) averaging 195±6g and 6761±181g, respectively. Litter weight at 28d tended (P=0.058) to be higher on ALBI litters (56.6±4.0kg) than BIAL litters (43.2±4.0kg). These results obtained within the frame of Treasure project are the first data available so far from this cross and it could be useful in future as reference for further studies and also for farmers that may try these crosses on a commercial basis.

Use of two doses of cloprostenol in different intervals for estrus synchronization in hair sheep under tropical conditions.

This study evaluated the effect of two doses of prostaglandin at different intervals on reproductive parameters of crossbred ewes. In Experiment 1, 30 ewes received two doses of 120μg cloprostenol at 7 (G 7days), 9 (G 9days), or 11.5 (G 11.5days) days apart. Ultrasound assessments were performed from the first and second cloprostenol administration for 5days or ovulation detection. Estrus signs were checked by a teaser male. Plasma progesterone concentration was measured before each cloprostenol dose. In Experiment 2, 95 ewes were allocated into the same treatments and after the second dose, ewes in estrus were mated. At 30days after breeding, pregnancy diagnosis was conducted and prolificacy was evaluated at lambing. In Experiment 1, at the first cloprostenol administration, 50% of ewes had an active CL and all showed estrus. At the second administration, 66.7% of ewes had an active CL and one did not present estrus. There was no difference (P>0.05) after the second dose for as follows: overall estrous response (90%), interval from cloprostenol administration to estrous onset (42.0±4.9h), estrus duration (31.5±2.1h), ovulation rate (100.0%), and number of ovulations (1.5±0.3). In Experiment 2, both pregnancy and prolificacy rates were similar (P>0.05) for G 7days (73.3; 145%), G 9days (75.9; 125%), or G 11.5days (75.9; 145%), leading to an overall pregnancy rate of 75.0% (66/88) and prolificacy rate of 137%. Therefore, the three treatments proposed were able to promote high pregnancy and prolificacy rates in crossbred ewes.

Insemination extender supplementation with bestatin and EDTA has no effect on rabbit reproductive performance

The addition of aminopeptidase inhibitors (AMIs) to rabbit semen extenders could be a solution to decrease the hormone degradation (GnRH) by the aminopeptidases existing in the seminal plasma. Therefore, the quantity of GnRH needed to induce ovulation in doe would be comparable with the amount administered intramuscularly (i.m.). This study was conducted to evaluate the effects of two AMIs (bestatin and EDTA) on rabbit semen quality parameters, β nerve growth factor (β-NGF) degradation and reproductive performance after artificial insemination. Results showed that seminal quality was not affected by the incubation with AMIs; the values of motility, acrosome integrity and sperm viability were not significantly different between the AMIs and the control groups (positive i.m. and negative intravaginally without AMIs). In addition, the aminopeptidase activity of seminal plasma was inhibited in a 55.5% by the AMIs as well as β-NGF degradation. On the other hand, regarding the effect of AMIs on reproductive performance, our results showed that the presence of bestatin and EDTA did neither affect fertility (85.3 vs. 88.6%), nor the prolificacy rate (10.12 vs. 10.51 kits per delivery), comparing AMIs group to positive control group, respectively. We conclude that the addition of specific AMIs in the rabbit semen extender has no effect on reproductive performance. Therefore, due to the fact that AMIs inhibit part of the aminopeptidase activity that degrades the GnRH analogue and β−NGF, they could be used to develop new extenders with less hormone concentration.

Comparative Study Regarding some Reproductive Parameters and Birth Weights in Rusty Tsigaia Breed and in Crossing with Blanc du Massif Central

The crossings of the Rusty Tsigaia breed with a meat breed, like Blanc du Massif Central, will increase the carcass characteristics of the crossed lambs, so this will correspond to the market demands. The aim of the study was to compare some reproductive parameters between two batches of 50 Rusty Tsigaia ewes (50 of pure breed and 50 crossed with BMC) for fertility, fecundity and prolificacy rate. Also the birth weight of the lambs was evaluated. The research was conducted on a selected flock of 100 Rusty Tsigaia sheep that were divided in two batches: 50 ewes were mated with Rusty Tsigaia rams and 50 ewes were mated with Blanc du Massif Central ram. After lambing, the birth weight was evaluated between the Rusty Tsigaia lambs and the lambs resulted from the crossing with BMC ram. The results were similar between the two batches concerning the conceiving, prolificacy and fecundity rate (Rusty Tsigaia rams x Rusty Tsigaia ewes and Blanc du Massif Central rams and Rusty Tsigaia ewes). Concerning the birth weights, the results showed a significant difference between the pure breed lambs and the crossed lambs, the crossed lambs having a superior weight.

Ovulation rate, prolificacy and pregnancy rate in goats treated with oral glycerol

This study tested whether the oral administration of glycerol at the time of progestin removal and in the first 6 days of the estrous cycle increased the ovulation rate, prolificacy, and pregnancy rate in goats. Intravaginal sponges impregnated with fluorogestone acetate were inserted into 129 goats for 12 days; upon sponge removal, goats were randomly assigned to one of the two following treatment groups: the glycerol group (n = 65), which received an oral drench of 100 mL of glycerol upon sponge removal and was repeated on days 0, 2, 4, and 6 following estrus (estrus = day 0), and the control group (n = 64), which did not receive glycerol. The goats in estrus were mated, and their ovulation rate was determined by ultrasonography between days 8 and 12 of the estrous cycle. Pregnancy was diagnosed by ultrasonography on day 40, and the prolificacy was determined at birth. In 6 goats treated with glycerol and 5 controls, their insulin concentrations at 0, 2, 4, 8, and 12 h after the glycerol drench were determined by radioimmunoassay. The proportion of goats with multiple ovulations (glycerol = 71 vs control = 64) and the proportion of goats with multiple births (glycerol = 52 vs control = 56) were similar (P &gt; 0.05) between treatments. Likewise, the pregnancy rate was similar (P &gt; 0.05) between treatments (glycerol = 88 vs control = 85%). The insulin concentrations tended to be higher in goats treated with glycerol (P = 0.08). In conclusion, an oral drench of 100 mL of glycerol at the time of progestin withdrawal and in the first 6 days of the estrous cycle did not increase the ovulation rate, prolificacy, or pregnancy rate in goats.

Ovulation rate, prolificacy and pregnancy rate in goats treated with oral glycerol

Ovulation rate, prolificacy and pregnancy rate in goats treated with oral glycerol

Evaluation of some reproductive parameters of Tsurcana sheep crossed with Blanc du Massif Central rams

The European market demands a better conformation in sheep carcass (class U or R). This carcass quality cannot be achieved in local Romanian breed - Tsurcana and Tsigaia - without a crossing with a specialized meat breed. The study was conducted with the aim to evaluate the fertility rate, in order to compare some reproductive parameters between the Tsurcana breed (Tsurcana rams x Tsurcana ewes) and the Blanc du Massif Central rams crossed with Tsurcana ewes. The research was conducted on a selected flock of 100 Tsurcana sheep that were divided in two batches: 50 ewes were mated with Tsurcana rams and 50 ewes were mated with 2 young Blanc du Massif Central rams, recently imported from France. The sheep included in the study were hormonal synchronized with progesterone and eCG (Equine Chorionic Gonadotropin). After mating the pregnancy diagnosis was performed by ultrasound examination at 55 and 130 days. The conceiving, the fecundity and prolificacy rate were assessed. The results were similar between the two batches concerning the conceiving, prolificacy and fecundity rate (Tsurcana rams x Tsurcana Ewes and Blanc du Massif Central rams and Tsurcana ewes).

Does the inclusion of protease inhibitors in the insemination extender affect rabbit reproductive performance?

The bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing aminopeptidases. Thus, the addition of aminopeptidase inhibitors to rabbit semen extenders could be a solution to decrease the hormone degradation. This study was conducted to evaluate the effect of the protease activity inhibition on rabbit semen quality parameters and reproductive performance after artificial insemination. Seminal quality was not affected by the incubation with protease inhibitors, being the values of motility, viability, and acrosome integrity not significantly different between the protease inhibitors and the control group. In addition, seminal plasma aminopeptidase activity was inhibited in a 55.1% by the protease inhibitors. On the other hand, regarding the effect of protease inhibitors on reproductive performance, our results showed that the presence of protease inhibitors affected the prolificacy rate (9.2 ± 0.26 and 9.3 ± 0.23 vs. 8.2 ± 0.22 total born per litter for negative control, positive control, and aminopeptidase inhibitors group, respectively; P < 0.05), having this group one kit less per delivery. We conclude that the addition of a wide variety of protease inhibitors in the rabbit semen extender negatively affects prolificacy rate. Therefore, the development of new extenders with specific aminopeptidase inhibitors would be one of the strategies to increase the bioavailability of GnRH analogues without affecting the litter size.

Analysis of major fecundity genes in autochthonous Laticauda and Bagnolese sheep breeds

Aim of this work was to analyze the fecundity genes BMPRIB (FecB allele), BMP15 (exon 2) and GDF9 (both exons) in two autochthonous sheep breeds, Laticauda and Bagnolese, reared in Campania region and characterized by a high prolificacy rate. Both breeds have an economic relevance due to the production of meat and milk. The analyses of fecundity genes ruled out the presence of the main alleles (FecB, FecXG, FecXH, FecXI), reported earlier to be associated with a high prolificacy rate in other breeds. Eleven SNPs were found in GDF9 exon 2, five of these for the first time, in particular at nt 531, 953 and 1203 in Bagnolese sheep and at nt 617 and 1358 in Laticauda sheep. In Bagnolese breed the association analysis of these SNPs with prolificacy rate showed a significantly higher value of litter size of GG individuals at nt 750 when compared with GA ewes.

The Use of Melengestrol Acetate as a Strategy to Improve Production Efficiency of Sheep in Rural Areas in Mexico

The aim of this study was to evaluate the use of melengestrol acetate (MGA) as a strategy to improve the production efficiency in ewes of rural areas in Mexico. Twenty ewes of breeds (Dorper and Dorper with Pelibuey) non-pregnant and with ovarica activity were used. The treatment consisted of the administration of 0.22 mg MGA/ewe/d for 17 d. The MGA efficiency was measured once the treatment finalized, and the producer was responsible for the registration of the estrus presentation and prolificacy rate. 95% of the sheep presented estrus in a period of 14 d after stopping treatment. The prolificacy percentage was of 1.2 lambs born by ewe during a period of six months (including treatment and period of gestation). In conclusion, the use of MGA represents an alternative to improve the efficiency of sheep production in rural areas in Mexico, since it can increase the number of lambs by 30% in a period of 12 months.