Effect of peripartum dexamethasone treatment on farrowing outcomes and newborn piglet traits in multiparous sows.

This study assessed the effects of dexamethasone treatment on farrowing performance and piglet traits in the first 5 days of life in multiparous sows, a high-risk group for stillbirths and prolonged farrowing. In this study, 185 multiparous sows (parity 4.25 ± 0.14) were selected on the day of farrowing and divided into three treatments: CON - control, without dexamethasone treatment; DexaPF - treatment with dexamethasone (20 mg im per female) at the time of copious colostrum secretion (pre-farrowing); and DexaFO - treatment with dexamethasone (20 mg im per female) when the first piglet was born (farrowing onset). All sows and their litters were monitored for farrowing duration, obstetric interventions, colostrum yield and intake, newborn piglet traits, and piglet performance until 5 d of age. A subsample of 106 females (∼35 per treatment) had their blood glucose concentration checked hourly shortly after the first piglet was born until the end of farrowing. Additionally, blood samples from 42 litters were collected for immunocrit evaluation. The results showed no differences regarding farrowing duration (CON = 258.02 ± 13.81 min; DexaPF = 251.29 ± 13.60 min; DexaFO = 294.92 ± 13.89 min; P = 0.06) and obstetric intervention rates among treatments (CON = 36.58 ± 6.78 %; DexaPF = 42.16 ± 6.89 %; DexaFO = 48.05 ± 7.08 %; P = 0.45). The blood glucose concentration during farrowing was higher in DexaPF (94.56 ± 1.57 mg/dL; P < 0.001) than in CON (73.50 ± 1.72 mg/dL) and DexaFO (87.94 ± 1.80 mg/dL). No differences were observed regarding total piglets born and born alive, stillborn, newborn piglet vitality, colostrum intake, immunocrit, colostrum yield, and glycemia and rectal temperature at 24 h of age (P ≥ 0.13). Regarding meconium staining, higher percentages of piglets born without meconium staining were observed in DexaFO (54.77 ± 5.21 %; P = 0.02) compared with CON (48.58 ± 5.26 %), and no difference was observed for the DexaPF group (53.23 ± 5.21 %). In addition, a higher unbroken umbilical cord rate was observed in DexaFO (92.41 ± 1.31 %; P < 0.01) than the CON or DexaPF (86.91 ± 1.97 % and 89.31 ± 1.67 %, respectively). However, the treatments did not affect piglet performance (weight gain and survival) until 5 d of age (P ≥ 0.15). In summary, dexamethasone treatment in periparturient multiparous sows did not improve farrowing performance and key production parameters, such as the piglet weight gain and survival up to 5 d of age.

L-cysteine improves boar semen motility at 5 ºC but does not affect the oxidative status.

Hypothermic storage has been proposed as a method to reduce bacterial loads and promoting prudent use of antibiotics. Reducing temperature, however, can lead to cold shock damage and oxidative stress in boar semen. This study verified the effect of L-cysteine on the quality of semen stored at 5 °C for 120 h. Twenty-one normospermic ejaculates were diluted in Beltsville Thawing Solution into five treatments: Positive control (Pos_Cont, storage at 17 °C without L-cysteine) and groups with 0, 0.5, 1, and 2 mmol/L of L-cysteine supplementation stored at 5 °C. Variables were analyzed as repeated measures, considering treatment, storage time, and interaction as main factors. The effects of different L-cysteine concentrations were also evaluated using polynomial orthogonal contrasts. Sperm motility and pH were higher in the Pos_Cont compared to the groups stored at 5 °C (P < 0.05). In polynomial orthogonal contrast models, total motility was affected by the interaction between L-cysteine and storage time (P = 0.04), with a linear increase in motility when increasing the amount of L-cysteine at 72 and 120 h. Progressive motility increased quadratically as the L-cysteine reached 1 mmol/L (P < 0.01). In the thermoresistance test at 120 h, sperm motility increased quadratically up to an L-cysteine dose of 1 mmol/L (P < 0.05). Sulfhydryl content linearly increased with L-cysteine supplementation (P = 0.01), with no effect on intracellular ROS and sperm lipid peroxidation (P ≥ 0.06) in 5ºC-stored doses. In conclusion, L-cysteine supplementation has a positive effect on sperm motility up to 120 h of storage at 5 °C.

Managing Reproduction in Hyperprolific Sow Herds.

The rearing of large litters from hyperprolific sows is a characteristic of modern genotypes. However, these sows have body and reproductive characteristics that differentiate them from the genotypes of the past decades, making it necessary to adopt different management strategies. This review describes the main care and challenges associated with the hyperprolificity of sows during the period in which replacement gilts are selected, along with gestation, parturition, lactation, and the weaning-estrus interval. It describes the challenges that these sows' piglets will face during the lactation period and includes some strategies adopted to develop these surplus piglets. In addition, it identifies areas where more research is needed to understand the reproductive management of modern genotypes.

Sperm concentration of boar semen doses and sperm quality: Novel perspectives based on the extender type and sperm resilience.

This study evaluated the effect of sperm concentration of boar semen doses on their capacity to maintain its motility over the thermo-resistance test (TRT; sperm resilience) and verified if the extender type (short or long-term) could influence this effect. Thirty ejaculates from five crossbred mature PIC® boars were used, and a factorial design was followed to produce semen doses with 1.5 billion cells in 45 or 90 mL, using Beltsville Thawing Solution (BTS) or Androstar® Plus (APlus). Then, low-concentration doses (16.7 × 106 cells/mL in 90 mL) and higher-concentration doses (33.3 × 106 cells/mL in 45 mL) with BTS or APlus were produced and stored at 17 °C for 168 h. At 72 h, during the TRT, the low-concentration doses (16.7 × 106 cells/mL) lost three-fold less motility than doses with 33.3 × 106 cells/mL (P < 0.01), regardless of the extender type (11. 5% vs. 30.5% of initial motility, respectively). Similar results were found when the TRT was carried out at 168 h, with low-concentration doses losing two-fold less motility (11.4%) than highly concentrated doses (25.9%; P < 0.01). No sperm concentration effect was observed on membrane integrity or mitochondrial membrane potential (P ≥ 0.23). The osmolarity was not affected by the sperm concentration (P = 0.56), only by the extender and the storage time (P < 0.01). In conclusion, the sperm concentration effect on sperm quality was not influenced by extender type, and the data suggest that a low concentration of semen doses positively affects sperm resilience.

Estimation of sperm concentration limits to produce intrauterine insemination doses in swine.

This study evaluated the effect of sperm concentration of boar semen doses, for intrauterine artificial insemination (IUAI), on semen quality and established concentration limits for their production. Twenty ejaculates from four crossbred mature PIC® boars were collected to produce 50 mL semen doses in a split sample, reaching the following sperm concentrations: ~20, 30, 60, and 100 × 106 cells/mL. Doses were produced using Androstar® Plus, stored at 17°C, and evaluated until 120 h of storage. There was a linear decrease in sperm motility as the sperm concentration increased (p linear < .01). The concentration which no longer affected the total and progressive motility was 59 and 55 × 106 cells/mL, respectively (corresponding to 71% and 62%, respectively). The pH linearly decreased as the sperm concentration increased (p < .01); yet, at 72 and 120 h, the parameter dramatically reduced in boar semen doses with 60 and 100 × 106 cells/mL. The percentage of cells with intact plasma and acrosomal membranes or with high mitochondrial membrane potential was not influenced by the sperm concentration (p ≥ .15). In conclusion, sperm motility was negatively affected in highly (60 and 100 × 106 cells/mL) concentrated doses. To achieve suitable sperm motility, boar semen doses may not surpass the sperm concentration of 55 × 106 cells/mL. The effect of low-concentrated boar semen doses on sperm quality still needs to be better evaluated, mainly considering the influence of extender type and thermo-resistance conditions.

Relationship between dexamethasone treatment around parturition of primiparous sows and farrowing performance and newborn piglet traits.

This study evaluated the relationship between the steroidal anti-inflammatory action of dexamethasone treatment in primiparous sows and farrowing and piglet performance in the first 5 d of life. For this purpose, 234 gilts were selected on the day of farrowing and distributed among three treatments: CON - control, without dexamethasone treatment; DexaPF - treatment with dexamethasone (20 mg im) per female at the moment of copious colostrum secretion (pre-farrowing); and DexaFO - treatment with dexamethasone (20 mg im), per female when the first piglet was born (farrowing onset). All females and their litters were evaluated regarding farrowing duration, obstetric interventions, colostrum yield and intake, newborn piglet traits, and piglet performance until 5 d of age. A subsample of 79 females (∼26 per treatment) had their blood glucose concentration evaluated hourly shortly after the first piglet was born until the end of farrowing. Additionally, blood samples from 11 litters per treatment were collected for immunocrit evaluation. As a result, faster farrowing was observed in the DexaPF treatment (188.14 min; P = 0.002) compared with CON (229.99 min) and DexaFO (221.79 min). Additionally, lower obstetric intervention rates were observed in sows treated with dexamethasone (DexaPF = 7.69%; DexaFO = 5.13%) compared with CON (19.23%; P = 0.02). The sow's blood glucose concentration during farrowing was higher in DexaPF (90.55 mg/dL) than in CON (73.15 mg/dL) and DexaFO (80.06 mg/dL) treatments (P < 0.01). Besides the effect on farrowing duration, no differences among treatments were observed regarding piglets born alive and stillbirths, newborn piglet vitality, colostrum consumption, immunocrit, and colostrum yield (P ≥ 0.17). Regarding piglet traits, higher percentages of piglets born without meconium staining and lower percentages of piglets with meconium scores 2 and 3 were observed in the groups treated with dexamethasone (DexaPF and DexaFO; P < 0.01) compared with CON. However, piglet weight gain and survival rate until 5 d of age were not affected by the treatment (P ≥ 0.61). In summary, dexamethasone treatment before farrowing onset, in primiparous sows, had the potential to reduce the farrowing duration and the necessity of obstetric intervention, but it did not affect the main productive parameters such as the occurrence of stillbirths, piglet weight gain, and survival rates until 5 d of age.

Reproductive performance of gilts and weaned sows grouped at different days after insemination.

The objective of the study was to compare the reproductive performances of gilts and weaned sows grouped at different days after insemination. The study was conducted on a sow farm in the Midwest of Paraná State, Brazil, using animals from the Camborough genetic line (PIC®, Patos de Minas, Brazil, Landrace × Large White crossbred). The groups of comparison have considered the distribution of gilts (n = 407) and sows (parity 1 to 5; n = 843) according to the day of group housing in collective pens in relation to the day of last insemination (AI). Thus, gilts were distributed in four groups of comparison: group housing on days 1, 2, 3, or 4 after the last AI (AI). Sows were distributed in three groups of comparison: group housing on the day after the last AI (0), at day 1 or 2 after the last AI. Farrowing rate (FR), the total number of piglets born (TB), and return to estrus (RE) were recorded. In a subsample (254 gilts and 622 sows), the presence and the score of skin lesions (0, no lesions; 1, low; 2, moderate; or 3, high) were evaluated 24 and 48 h after mixing. Statistical analysis was performed using the SAS® 9.4 software using the GLIMMIX procedure. Comparisons of means were performed using the Tukey-Kramer test and frequencies by logistic regression. Group housing gilts on different days after insemination did not affect FR, TB, and RE (P ≥ 0.79). However, sows mixed 2 days after AI had a reduction in TB compared to those mixed on day 1 (P = 0.05), without differences from sows mixed on the day of the last AI. All the females had low (score 1; 60.5%) or moderate (score 2; 39.5%) skin lesions. For both female categories, the presence of low or moderate lesion scores did not affect ER, FR, and TB (P ≥ 0.25). Fights within 48 h were not severe enough to compromise reproductive performance (P ≥ 0.25). In conclusion, group housing gestating sows 2 days after breeding compromised litter size; however, mixing gilts on days 1 to 4 after breeding did not impair reproductive performance.

A 5-color flow cytometry panel to assess plasma membrane integrity, acrosomal status, membrane lipid organization and mitochondrial activity of boar and stallion spermatozoa following liquid semen storage.

For a more practically applicable analysis of different sperm characteristics, this study aimed to develop a 5-color flow cytometry (FC) panel to concurrently analyze four sperm parameters in liquid boar and stallion semen, using also a DNA-marker for selecting sperm cell events. From each of thirty extended boar semen doses and twelve stallion semen doses, six aliquots were taken. For evaluating mitochondrial activity (A), degree of lipid disorder of plasma membrane (B), integrity of plasma membrane (C), acrosomal status (D) and marking DNA (E), five aliquots were individually stained with Rhodamine 123, Merocyanine 540, Propidium Iodide, PNA-Alexa Fluor 647, and Hoechst 33342, respectively. The sixth aliquot was stained with all the five fluorochromes simultaneously, whereas spectral overlap was corrected by a compensation matrix. Strong correlations were found between the single and 5-color staining assays for boar sperm (A: 0.99, B: 0.96, C: 0.93, D: 0.98, E: 0.99; P < 0.01). Furthermore, moderate and substantial Concordance Correlation Coefficients (CCC) were presented by all these parameters (0.99, 0.96, 0.92, 0.98, and 0.99, respectively). For stallion sperm, the correlation coefficients between the assays were also strong (A: 0.99, B: 0.98, C: 0.99, D: 0.99, E: 0.95; P < 0.01) and substantial CCC were observed for all of them (0.99, 0.97, 0.99, 0.99, and 0.90, respectively). For both species, the mean difference between the methods (d̅) did not overtake 0.84. The results confirmed that this 5-color panel could be successfully implemented for analyzing boar and stallion sperm quality in a single, practical and quick FC assay.

Altrenogest treatment during the last week of lactation on ovarian traits and subsequent reproductive performance of primiparous and multiparous sows.

High-quality follicles result in larger corpora lutea (CL), producing more progesterone, and having a fundamental role in pregnancy maintenance. For some sows, follicular growth takes place during lactation, and follicle selection occurs under a catabolic environment. As altrenogest inhibits follicular development, this study aimed to evaluate follicular growth, CL size, estrus expression, and subsequent reproductive performance of sows treated with altrenogest during the last seven days of a three-week lactation. A total of 81 primiparous and 319 multiparous sows were allocated to two treatments: CONT (control group) and ALT (20 mg of altrenogest/day during the last seven days of lactation). Subsamples of 20 primiparous sows and 97 multiparous were randomly selected to evaluate follicular growth and 26 multiparous sows for serum progesterone analysis at day 21 of gestation. On day 21 of pregnancy, CL measurement was performed by ultrasound. Once in estrus, sows were post-cervically inseminated with pooled semen doses with 1.5 × 109 sperm cells at estrus onset and every 24 h during the standing reflex period. Sows not showing estrus until 10 days after weaning were considered in anestrus. The variables weaning-to-estrus interval, CL size, litter size in the subsequent cycle, and piglet birth weight were evaluated using the GLIMMIX procedure and compared using the Tukey-Kramer test. Anestrus, pregnancy, farrowing, and adjusted farrowing rate were evaluated as binary responses using logistic regression. Follicular size was analyzed as a repeated measure during treatment and after weaning. Treatment was considered as a fixed effect. During the treatment period, follicular size was smaller in ALT sows than CONT sows (3.29 vs. 3.52 mm; P < 0.001). However, after treatment, ALT sows showed a larger follicular size than CONT sows (5.30 vs. 5.03 mm; P ≤ 0.01). There were less ALT sows showing estrus than CONT sows on days three (1.03 vs. 4.57%) and four (55.38 vs. 68.02%) after weaning (P ≤ 0.05), respectively. At 21 days after insemination, ALT sows showed larger CL size and lower CL size variation (P < 0.01) than CONT sows. Anestrus rate, pregnancy rate, farrowing rate, adjusted farrowing rate, litter size in the subsequent cycle, piglet birth weight, litter birth weight, and birth weight variation did not differ between treatments (P ≥ 0.14). In conclusion, altrenogest treatment during the last week of lactation concentrated estrus expression on day five after weaning, larger follicle and CL sizes; however, with no improvement in reproductive performance.

Sow-related factors affecting the postweaning feed intake in Landrace × Large White females.

During the weaning-to-estrus interval (WEI), a high feeding level is usually offered to recover losses due to lactational catabolism. However, several factors can affect the appetite, possibly impairing the efficacy of this strategy. This study aimed to investigate the effect of sow-related factors on average daily feed intake (ADFI) during WEI in 142 primiparous and 458 multiparous sows. After weaning, the sows received 4.3 kg/day of feed and the wastage was recorded. The ADFI after weaning was lower in primiparous than multiparous sows, and on estrous day than in 2 and 3 days preceding estrus (P ≤ 0.05). In primiparous sows, lower ADFI was observed if they had higher backfat thickness at 112 days of gestation (BFT ≥ 11.5 mm) or higher reserves at weaning (BFT ≥ 10.5 mm, caliper units ≥ 12 or ≥ 157 kg; P ≤ 0.05). Higher body reserves at the end of gestation (caliper units ≥ 12, BFT ≥ 11.0 mm, or BCS ≥ 3.0) or weaning (caliper units ≥ 13, BFT ≥ 12.5 mm) negatively affected the ADFI in multiparous sows (P < 0.04). Weaned litter size ≤ 11 piglets (P = 0.06) and shorter lactation length (P< 0.01) decreased the ADFI in primiparous sows. Greater loss in caliper units during lactation tended to reduce ADFI in primiparous and multiparous sows (P ≤ 0.07). Multiparous sows with greater losses in BFT and BCS had lower ADFI (P ≤ 0.03). The ADFI during WEI is reduced when sows are in estrus or if they have greater body reserves.

Adjusted method of penis fixation during boar semi-automatic semen collection aiming to reduce bacterial contamination.

Semen collection has an essential role in the initial bacterial load in boar ejaculates and extended semen. The study aimed to explore the efficacy of an adjusted penis fixation in a semi-automatic collection system on reducing bacterial contamination of ejaculates in two-boar studs with different scenarios. Historically, stud A had low levels of bacterial load in raw semen, while stud B had a high level of contamination. A total of 56 mature boars had their semen collected using two methods of penis fixation: (a) Traditional: The penis was fixed directly with the artificial cervix and transferred to the adjustable clamp; (b) Adjusted: The fixation was performed with one gloved-hand, and after exteriorization, the penis was gripped using the artificial cervix with the other gloved-hand and transferred to the adjustable clamp. The bacterial load (p = .0045) and the occurrence of ejaculates >231 CFU/ml (p = .0101) were reduced in the Adjusted compared to the Traditional method. Bacterial load was reduced when using the Adjusted method in stud B (p = .0011), which showed a greater occurrence of critical factors for bacterial contamination (p ≤ .0034). The Adjusted method reduced the occurrence of ejaculates >231 CFU/ml when the preputial ostium was dirty (p = .016) and the duration of semen collection was >7 min (p = .022) compared to the Traditional method. In conclusion, the Adjusted penis fixation was efficient in reducing bacterial load of ejaculates, mainly in boar stud B, which had high contamination challenges.

Reproductive performance in gilts following applications of different insemination doses and techniques.

This study evaluated the applicability of intrauterine artificial insemination (IUAI) in gilts and the impact of age at insemination and different body characteristics of gilts on the success rate for cannula insertion. Additionally, reproductive performance was evaluated for IUAI and cervical artificial insemination (CAI), considering different semen dose sizes. A total of 636 gilts were assigned in a 2 × 2 factorial design: two artificial insemination techniques (CAI and IUAI) and two semen dose sizes (1.5 × 109 sperm cells/50 mL or 2.5 × 109 sperm cells/80 mL). In those gilts assigned to IUAI (n = 319) the success rate for intrauterine cannula insertion was evaluated according to weight at first detected estrus, body condition score (BCS), and age at insemination. Reproductive performance, occurrence of bleeding, and semen backflow during all inseminations were compared among groups (2 × 2). Two subgroups were evaluated regarding the time expended to perform insemination (n = 380), and the semen backflow collected during 1 h after insemination (n = 114). The success rate for intrauterine cannula insertion, based on a successful insertion in all inseminations performed during estrus, was 58.9%. Additionally, greater possibility (>60%; P ≤ 0.04) of cannula insertion was observed in heavier gilts (≥124 kg), as well as in older gilts (≥225 d) and those with greater BCS (>3). There were no differences among the groups in pregnancy rate (≥95.3%; P = 0.23), farrowing rate (≥93.7%; P = 0.54), total piglets born (≥14.5; P = 0.45), as well as, bleeding (P = 0.48) and backflow (P = 0.48) during insemination. However, the percentage of semen backflow volume and percentage of sperm cells in the backflow were lower in gilts inseminated by CAI with 1.5 billion sperm cells/50 mL (P < 0.01) than in the other groups. There was no expressive reduction in time expended to perform IUAI compared to CAI. However, gilts inseminated with 1.5 billion sperm cells/50 mL showed a lower total time to inseminate than all other groups (P < 0.01). In conclusion, higher weight, BCS, and age increased the success rate for cannula insertion. However, IUAI did not optimize the insemination procedure, and remains limited for gilts due to the low success rate for cannula insertion. Reproductive performance was not affected by IUAI or CAI using 1.5 or 2.5 billion sperm cells in 50 or 80 mL, respectively, suggesting the possibility of using CAI with 1.5 billion sperm cells/50 mL in gilts.

Effects of the classification of boars according to progressive sperm motility and the extender type on the reproductive performance of a single fixed-time insemination.

The study aimed to evaluate the fertility of boars according to the resistance of their semen to storage using dilution in either Short- or Long-term extender for single fixed-time insemination. From a total of 32 boars, twelve boars were classified during three semen collection (one collection/boar/week) as Low- (64.5%) or High-preservation (83.9%) capacity for maintaining progressive motility (PM) at 120 h of storage using Short-term extender. After the selection period, six ejaculates (weekly collected) from the Low- and High-preservation boars were diluted in Short- or Long-term extender (2 × 2 factorial design) for insemination and evaluation of fertility. A total of 519 weaned sows were submitted to induction of ovulation with triptorelin (OvuGel®) at 96 h post-weaning. Twenty-four hours later, estrus sows were single fixed-time inseminated (FTAI) with semen doses from the different groups of evaluation. The SAS® software was used for statistical analysis considering the class of boar, type of extender, and interaction as fixed effects. The GLIMMIX procedure was used, considering a binomial distribution for total motility (TM) and PM, binary distribution for pregnancy (PR), and farrowing rate (FR), and the total born (TB) was analyzed assuming a normal distribution with the comparison of means by Tukey-Kramer test. An interaction of class of boars and type of extender was observed for TM and PM at insemination (P < 0.001). Long-term extender increased TM in Low-preservation boars, with no effect in High-preservation boars. The ejaculates from High-preservation boars diluted in Short- or Long-term extender showed higher PM at insemination (86.8 and 87.8%, respectively) compared to those from Low-preservation boars in Short- or Long-term extender (73.2% and 77.9%, respectively). There was no effect of the interaction of boar preservation class and type of extender (P ≥ 0.163) on PR, FR or TB. However, Low-preservation boars presented lower TB (14.1 ± 0.2) compared to High-preservation boars (15.0 ± 0.2; P < 0.01). The PR (93.3 vs. 90.1) and FR (88.8 vs. 88.2) were not affected by class of Low- or High-preservation boars, respectively (P ≥ 0.187). The type of extender did not affect PR, FR, or TB (P ≥ 0.440). In conclusion, Low-preservation boars impaired the reproductive performance of single-FTAI sows by reducing TB with no apparent effect on PR or FR.

Perspectives of intrauterine artificial insemination applicability in gilts / Perspectivas de aplicabilidade da inseminação artificial intrauterina em leitoas

The application of the intrauterine artificial insemination (IUAI) technique allows optimization of a swine production system due to the reductions in volume and number of sperm cells in the insemination dose, and by reducing the time taken to perform the insemination. However, IUAI is not recommended for gilts due to the difficulty of intrauterine cannula passage through the cervix. This difficulty is associated mainly with the fact that the reproductive tract is smaller in gilts than in pluriparous females. However, few studies have evaluated the application of IUAI in gilts. In these studies, there are variations in approach concerning the definition of the success rate for cannula passage through the cervix, the type of cannula and the body characteristics of the gilts used, making it difficult to extrapolate the recommendation for the use of IUAI in gilts. Considering the evidence that such characteristics influence or even determine the success of the application of IUAI, there is a necessity for an understanding of the influence of these factors in the improvement and later application of the technique. Gilts represent about 15-20% of the breeding group, and the use of IUAI could optimize the processes of insemination on farms. The approach used in this review highlights the aspects that could aid in structuring further studies for improving IUAI in gilts, allowing its use on commercial farms.(AU)

A aplicação da técnica de inseminação artificial intrauterina (IAU) permitiu uma otimização do sistema de produção de suínos por possibilitar a redução do volume e número de células espermáticas na dose inseminante e, também, por diminuir o tempo de execução da inseminação. Porém, a IAU não tem sido recomendada para leitoas devido à dificuldade de passagem do cateter intrauterino através da cérvix. Essa dificuldade é associada principalmente ao menor tamanho do trato reprodutivo de leitoas se comparado ao das fêmeas pluríparas. Entretanto, ainda são poucos os estudos que avaliaram a aplicação de IAU em leitoas. Nesses estudos, existem variações quanto à definição da taxa de sucesso na inserção do cateter através da cérvix, ao tipo de cateter e, também, quanto às características corporais das matrizes utilizadas, dificultando extrapolações de recomendação do uso da IAU em leitoas. Considerando os indícios de que tais características podem influenciar ou, até mesmo, determinar o sucesso de aplicação da técnica, ainda há necessidade de compreender a influência desses fatores para que a técnica possa ser aprimorada e posteriormente aplicada. Leitoas representam cerca de 15 a 20% do grupo de cobertura e viabilizar a IAU nessa categoria pode otimizar os processos de inseminação nas granjas. A abordagem realizada nessa revisão traz aspectos que podem auxiliar na estruturação de futuros estudos para aprimorar a IAU em leitoas e permitir seu emprego em granjas comerciais.(AU)

Follicular dynamic and reproductive performance of gilts submitted to estrous cycle synchronization using two different progestogen sources.

This study evaluated reproductive indicators of gilts treated with altrenogest or an intravaginal device (IVD) containing medroxyprogesterone acetate (MPA) for estrous cycle synchronization, starting the protocol on different days of the estrous cycle or replacing the IVD in the middle of treatment. In Experiment 1, 126 gilts were assigned, according to the day of treatment onset (Day 5 or 10 of the estrous cycle), to the following treatments: Control-5 (no hormone); Control-10 (no hormone); IVD-5 (IVD with MPA); IVD-10 (IVD with MPA); ALT-5 (altrenogest); or ALT-10 (altrenogest). The first day of the previous estrus was considered as Day 0 of the estrous cycle, and progestogen groups were treated for 14 d. In Experiment 2, 63 gilts were assigned to Control, ALT, or IVD groups. Progestogen treatment started on Day 10 of the estrous cycle, and the IVD was replaced after 7 d of treatment. In both experiments, no gilts expressed estrus during progestogen administration. In Experiment 1, the interval hormonal withdrawal-to-estrus (IHE) tended to be shorter when treatment started on Day 10 than on Day 5 (3.6 vs. 4.1 d, respectively; P = 0.09). The percentage of gilts expressing estrus after hormone withdrawal was lower for IVD-gilts (76.3%) compared to ALT (100%) and Control-gilts (92.9%; P ≤ 0.07). The percentage of persistent follicles (PFOL) was greater in IVD-10 (60.0%) and ALT-10 (33.3%) than CONT-10 (0.0%; P ≤ 0.06). The adjusted farrowing rate (AFR) was lower in IVD (65.5%) and ALT (80.5%) compared with CONT (97.4%; P ≤ 0.08). In Experiment 2, the IHE was longer for ALT than IVD (4.9 vs. 3.9 d, respectively; P < 0.01). No difference among groups was observed in the percentage of gilts expressing estrus (overall 86.4%), but the occurrence of PFOL was higher in IVD (61.5%) compared to ALT (5.3%), and Control groups (10.5%; P < 0.01). The AFR was lower in IVD (53.8%) than in ALT (88.2%) and Control (94.7%; P ≤ 0.05). The total number of piglets born was not affected by hormonal treatments in either experiment. Estrous expression was delayed in gilts treated with altrenogest or IVD-MPA. However, the reproductive performance of IVD-gilts was compromised, which was not circumvented by IVD replacement in the middle of treatment. Therefore, further studies are necessary to understand MPA pharmacodynamics and investigate alternative devices for a steady release of progestogens in gilts.

Antibiotic-free extended boar semen preserved under low temperature maintains acceptable in-vitro sperm quality and reduces bacterial load.

This study aimed to assess the sperm quality and number of colony-forming units (CFU mL-1) in extended boar semen stored at low temperatures with or without antibiotics. Normospermic ejaculates (n = 34) were diluted in split samples with Androstar® Premium with or without antibiotics (ampicillin and apramycin sulfate). The extended semen doses were stored for 120 h under three storage temperatures (5, 10, and 17 °C). Variables were analyzed as repeated measures using the GLIMMIX procedure, in a factorial design. The extended semen doses under low-temperature storage (5 and 10 °C) had total motility above 75% throughout the storage. The interaction antibiotic × temperature was significant for total (P = 0.004) and progressive motility (P = 0.005). In extended boar semen doses with antibiotics, the total and progressive motility increased as the storage temperature increased (80.2%, 84.5%, and 89.1%; 70.5%, 76.0%, and 82.9% for total and progressive motility at 5, 10, and 17 °C, respectively; P < 0.05). In extended semen doses without antibiotics, the total and progressive motility were lower when stored at 5 °C than at 10 °C and 17 °C (81.8%, 85.4% and 86.6% and 71.9%, 76.7%, 78.9% for total and progressive motility at 5, 10, and 17 °C, respectively; P < 0.05). After the thermoresistance test, total and progressive motility of doses with antibiotics were higher at 17 °C than 5 °C (P < 0.05); however, they were not affected (P > 0.05) by storage temperature in extended semen doses without antibiotics. The number of CFU mL-1 was lower in extended semen doses without antibiotics stored at 5 and 10 °C than at 17 °C (P < 0.05); however, in extended semen doses with antibiotics, no effect of storage temperature was observed (P > 0.05). The bacterial load was greater in extended semen without antibiotics than with antibiotics, regardless of the storage temperature (P < 0.05). The acrosome and sperm membrane integrity were not influenced (P > 0.05) by using antibiotics. A higher percentage of normal acrosomes was observed as the storage temperature increased (93.6%, 94.3%, and 96.8% at 5, 10, and 17 °C, respectively; P < 0.0001). The membrane integrity was higher (P < 0.0001) in extended semen doses stored at 17 °C than at 10 or 5 °C. The pH rose throughout the storage in all the treatments, except in extended semen doses stored at 17 °C without antibiotics, in which a decrease in the pH occurred at 120 h (P < 0.05). Although the sperm quality being negatively affected by low temperatures, the storage of extended boar semen doses at 5 °C is possible since the sperm viability in vitro was maintained for up to 5 days, fulfilling the requirements of semen quality to be used in artificial insemination. Nevertheless, the use of extended semen doses without antibiotics requires the optimization of hygiene procedures during semen dose processing.

Differential seminal plasma proteome signatures of boars with high and low resistance to hypothermic semen preservation at 5°C.

BACKGROUND: Hypothermic storage at 5°C has been investigated as an alternative to promote the prudent use of antibiotics for boar artificial insemination doses. However, this temperature is challenging for some ejaculates or boars. OBJECTIVE: The present study aimed to identify putative biomarkers for semen resistance to hypothermic storage at 5°C by comparing the seminal plasma proteomes of boars with high and low seminal resistance to preservation at 5°C. MATERIALS AND METHODS: From an initial group of 34 boars, 15 were selected based on the following criteria: ejaculate with ≤20% abnormal spermatozoa and at least 70% progressive motility at 120 hours of storage at 17°C. Then, based on the response to semen hypothermic storage at 5°C, boars were classified into two categories: high resistance-progressive motility of >75% in the three collections (n = 3); and low resistance-progressive motility of <75% in the three collections (n = 3). Seminal plasma proteins were analyzed in pools, and differential proteomics was performed using Multidimensional Protein Identification Technology. RESULTS: Progressive motility was lower at 120 hours of storage in low resistance, compared to high resistance boars (P < .05). Acrosome and plasma membrane integrity were not affected by the boar category, storage time, or their interaction (P ≥ .104). Sixty-five proteins were considered for differential proteomics. Among the differentially expressed and exclusive proteins, the identification of proteins such cathepsin B, legumain, and cystatin B suggests significant changes in key enzymes (eg, metalloproteinases) involved in spermatogenesis, sperm integrity, and fertilizing potential. DISCUSSION AND CONCLUSION: Differences in the seminal plasma suggest that proteins involved in the proteolytic activation of metalloproteinases and proteins related to immune response modulation could disrupt key cellular pathways during spermatogenesis and epididymal maturation, resulting in altered resistance to chilling injury. Further in vivo studies focusing on the immunological crosstalk between epithelial cells and gametes might explain how the immune regulators influence sperm resistance to hipothermic storage.

Reproductive performance of fixed-time artificial insemination in swine and factors for the technology success / Desempenho reprodutivo da inseminação artificial em tempo fixo em suínos e fatores para o sucesso da tecnologia

Fixed-time artificial insemination (FTAI) is a reproductive technology that aids in obtaining an appropriate time to perform single artificial insemination (AI), thus reducing the number of inseminations per sow bred. FTAI protocols can either be based on estrus detection or day of weaning, aiming to synchronize ovulation using ovulation inducers. The protocols involving estrus detection usually employ porcine luteinizing hormone (pLH) as an inducer and, in general, satisfactory reproductive performance is observed. For protocols based on weaning day, the main hormone used is analog of gonadotropin-releasing hormone such as triptorelin and buserelin. Regardless of the protocol, the number of piglets born is usually not affected by FTAI. However, a possible compromise in the farrowing rate should be considered. The FTAI in gilts requires progestogen treatment for estrus synchronization, increasing the labor requirement and cost of protocol. Some of the benefits of FTAI are a reduced number of semen doses required, advantage of planning the breeding time and; consequently, optimizing labor involved. However, the limitations include a slight reduction in the fertility index due to the compromised farrowing rate in some cases, costs incurred by following the protocol, and difficulty in measuring all the conceptual benefits under commercial conditions. The aim of this review is to approach the reproductive performance of the current protocols of FTAI, considering the benefits and limitations of this technology in swine production.(AU)

A inseminação artificial em tempo fixo (IATF) surge como uma biotecnologia para definir o melhor momento para realizar uma única IA, reduzindo o número de células espermáticas por fêmea inseminada. Os protocolos de IATF podem se basear na detecção do estro ou na data de desmame e têm como objetivo sincronizar a ovulação a partir do uso de indutores da ovulação. Protocolos baseados na detecção de estro comumente utilizam o hormônio luteinizante suíno (pLH) como indutor e, de maneira geral, resultados satisfatórios têm sido observados quanto à performance reprodutiva. No caso dos protocolos baseados na data de desmame, os principais hormônios utilizados são os análogos do hormônio liberador de gonadotrofina: triptorelina e buserelina. Independentemente do protocolo, o número de nascidos totais normalmente não é afetado pelo uso da IATF. Porém, um possível comprometimento na taxa de parto deve ser considerado. Já a aplicação da IATF em leitoas requer o fornecimento de um progestágeno, para sincronização do estro, aumentando o manejo e o custo do protocolo. A IATF pode proporcionar diversos benefícios para a indústria suinícola, uma vez que é possível reduzir o número de doses de sêmen produzidas, melhorar o planejamento de coberturas e, consequentemente, otimizar a mão de obra. No entanto, essa biotecnologia apresenta limitações devendo ser considerado a redução nos dados de fertilidade, uma vez que a taxa de parto pode ser comprometida em alguns casos e, o custo do protocolo e a dificuldade de estimar todos os benefícios conceituais da IATF quando aplicada sob condições comerciais. O objetivo dessa revisão é abordar o desempenho reprodutivo dos mais recentes protocolos de IATF, considerando os benefícios e as limitações dessa tecnologia na produção de suínos.(AU)

Atualizações na avaliação andrológica em suínos / Updates in breeding soundness evaluation in swine

O exame andrológico é uma ferramenta importante para o manejo reprodutivo do rebanho, uma vez que compreende etapas como, anamnese, exame clínico geral e dos órgãos genitais, avaliação do comportamento sexual, além da avaliação da produção, motilidade e morfologia espermática. Apesar de apresentar uma estrutura simples, o exame andrológico deve ser bem executado em cada uma de suas etapas, pois por meio desse procedimento é possível identificar precocemente e remover do rebanho machos inaptos à reprodução. Sendo assim, é fundamental ter conhecimento sobre as características anatômicas e fisiológicas básicas da espécie, e sobre os avanços obtidos em andrologia suína nos últimos anos para realizar adequadamente o exame e, consequentemente, beneficiar toda a cadeia produtiva de suínos.(AU)

Breeding soundness evaluation is a valuable tool for herd management, since the exam includes anamnesis, general and physical exams, boar sexual behavior, and the traditional exams such as sperm production, sperm motility and sperm morphology evaluations. Regardless of its easy execution, examinations must be well performed, considering every step, since this procedure allows the early identification of boars unsuitable for reproduction and their removal from a herd. Thus, it is essential to know about anatomic and physiologic aspects of this species and the updates in swine breeding soundness over the last years, in order to perform this exam properly and, consequently, bringing benefits for whole swine production.(AU)