Optimizing gilt mammary development to increase future milk yield

Sows do not produce enough milk to sustain optimal growth of their litters. This is particularly important when considering the current hyperprolific sow genetic lines. Mammary development needs to be considered to improve potential milk yield. One can only attempt to stimulate mammogenesis during periods when rapid mammary development is already ongoing. There are two such periods before lactation starts, namely, from three months of age until puberty, and from 90 days of gestation until farrowing. Early studies showed that a 20% feed restriction from 90 days of age until puberty drastically reduces mammary parenchymal tissue mass. Yet, in a more recent study, sow milk yield was not altered following a 10% or 20% feed restriction, or a 25% dietary fibre addition from 90 days of age to breeding. This absence of effect was likely due to the greater feed intake of control gilts in that recent study compared with the older studies, and suggested that feed intake of growing gilts can be reduced to 2.7 kg/d (but not 2.1 kg/d) without detrimental effects on future milk yield. During prepuberty, inclusion of the phytoestrogen genistein in the diet increases the number of mammary parenchymal cells. During late gestation, feeding very high energy levels may have detrimental effects on mammary development and subsequent milk production. Feed intake throughout gestation is also important because of its effect on body condition, with gilts that are too thin (< 16 mm backfat thickness) in late gestation showing less mammary development. A 40% increase in lysine intake via inclusion of additional soybean meal to the diet of gilts from days 90 to 110 of gestation increased mammary parenchymal mass by 44%. Increasing circulating concentrations of the growth factor IGF-1 during late gestation also increased mammary parenchymal mass by 22%. Current data clearly demonstrate that feeding management before lactation can be used to enhance mammary development, hence future milk yield.(AU)

The Influence of porcine parity on colostrum cytokine levels and their passive transfer to piglets / A influência da paridade suína na diferença dos níveis de citocinas no colostro e na transferência passiva para leitões

The limited ability of newborn piglets to produce cytokines may influence lymphocyte development and response to antigen exposure. As a result, colostrum intake is crucial because it contains nutrients that contribute to immune system development in piglets. Our goal was to investigate the effect of sow parity on the transfer of maternal cytokines to nursing piglets. Sixty piglets from nine sows were divided into six groups: piglets from gilts or sows kept with their dams and allowed to suckle normally; piglets from gilts or sows having their dams exchanged and then allowed to suckle normally; piglets from gilts or sows isolated from their dams and bottle-fed a commercial milk replacer formula for pigs. All piglets remained in the diet groups for 24 hours after birth. Concentrations of cytokines in colostrum and serum of gilt/ sows and serum of piglets were then evaluated. The 13 evaluated cytokines had higher concentrations in colostrum and serum of sows than in gilts. Concentrations of GM-CSF, IFNγ, IL-1α, IL-1ß, IL-2, IL-4, IL-6, IL-10, IL-12, IL-18, and TNFα were higher in piglets suckling sows. Piglets that received commercial formula showed higher concentrations of the cytokines IL1-RA and IL-8 than piglets fed colostrum. This outcome can influence piglets' development into adulthood. In short, our findings demonstrated that maternal parity influenced colostrum cytokine composition and its maternal transfer patterns.(AU)

A capacidade limitada dos leitões recém-nascidos de produzir citocinas pode influenciar o desenvolvimento de linfócitos e a resposta à exposição ao antígeno. Portanto, a ingestão de colostro é importante porque contém nutrientes, que contribuem para o desenvolvimento do sistema imunológico do leitão. O objetivo do estudo foi investigar o efeito da paridade da porca na transferência de citocina materna para leitões lactentes. Sessenta leitões de nove porcas foram divididos em seis grupos: leitões de marrãs/porcas mantidas com suas próprias mães e amamentadas normalmente; leitões de marrãs/porcas que foram trocados de mães e amamentados normalmente; leitões de marrãs/porcas que foram isolados das mães e alimentados com mamadeira com substituto do leite para suínos. Os leitões permaneceram nos grupos por 24 horas após o nascimento. Foram avaliadas as concentrações de citocinas no colostro e plasma das marrãs/porcas e no plasma dos leitões. O colostro e o plasma das porcas apresentaram maiores concentrações das 13 citocinas analisadas do que as marrãs. No mesmo sentido, as concentrações de GM-CSF, IFNγ, IL-1α, IL-1ß, IL-2, IL-4, IL-6, IL-10, IL-12, IL-18 e TNFα foram significantemente maiores nos leitões que mamaram o colostro de porcas. Os leitões que receberam fórmula comercial apresentaram, em especial, concentrações das citocinas IL1-RA e IL-8 superiores aos leitões amamentados com colostro. Isso pode influenciar o desenvolvimento até a fase adulta. Portanto, nossos dados demonstraram que a paridade materna influenciou a composição das citocinas do colostro, bem como as características das citocinas na transferência materna.(AU)

Behavioral and physiological performance of different gilt breeds during lactation

We evaluated the maternal behavior, physiology, and reproductive performance of both Damin (Min-pig × Large White) and Large White gilts to identify the advantages hybrid sows offer with regard to stress relieve and improvement of the welfare level of sows during late lactation. First-parity Damin gilts (n = 40) and firstparity Large White gilts (n = 40) were farrowed in individual pens. Video surveillance was used to monitor the occurrence of lateral recumbency and compare it to other postures, such as ventral recumbency, defecation, urination, tail posture, sham-chewing, and bar-biting behaviors. Monitoring was conducted from 07:00 to 09:00 h and from 13:00 to 15:00 h on days 3 and 6 of each week from the third to the fifth week postparturition. In addition, the concentrations of tumor necrosis factor-α, interleukin-6, and salivary α-amylase were assessed. During the fourth week postpartum, Damin gilts showed a higher frequency of postural changes from lateral recumbency to other postures and less ventral recumbency, sham-chewing, and bar-biting behavior compared with Large White gilts. However, no significant differences were found between Damin and Large White gilts with regard to urination, defecation, tail wagging, and "tail low" behaviors. The concentrations of serum interleukin-6, salivary α-amylase, and serum tumor necrosis factor-α were higher in Damin gilts than in Large White gilts during the fifth week postpartum. Damin gilts partly achieve lower stress levels during late lactation and better animal welfare than purebred Large White gilts.(AU)

Effect of parity segregation on Mycoplasma hyopneumoniae infection dynamics and pneumonic lesions in pigs / Efeito da ordem de parto segregada sobre a dinâmica de infecção de Mycoplasma hyopneumoniae e lesões pulmonares ao abate

Gilts represent a group risk for Mycoplasma hyopneumoniae vertical transmission in swine herds. Therefore, parity segregation can be an alternative to control M. hyopneumoniae infections. The study evaluated the effect of parity segregation on M. hyopneumoniae infection dynamics and occurrence and severity of lung lesions at slaughter. For that, three multiple site herds were included in the study. Herd A consisted of the farm where gilts would have their first farrowing (parity order (PO) 1). After the first farrowing PO 1 sows were transferred to herd B (PO2-6). Herd C was a conventional herd with gilt replacement (PO1-6). Piglets born in each herd were raised in separated nursery and finishing units. Sows (n = 33 (A), 37 (B), 34 (C)) in all herds were sampled prior to farrowing and piglets (n = 54 (A), 71 (B), 66 (C)) were sampled longitudinally at 21, 63, 100, 140 days of age and at slaughter for M. hyopneumoniae detection by PCR and lung lesions scoring. M. hyopneumoniae prevalence in sows did not differ among herds. Prevalence of positive piglets was higher at weaning in the PO1 herd (A) (P < 0.05). However, prevalence of positive pigs from 100 days of age to slaughter age was higher in the PO2-6 herd (B) (P < 0.05). Lung lesion occurrence and severity were higher in herd B. The authors suggested that the lack of a proper gilt acclimation might have influenced the results, leading to sows being detected positive at farrowing, regardless of the parity.

As leitoas consistem em um grupo de risco na transmissão vertical de Mycoplasma hyopneumoniae dentro do sistema de produção de suínos. Dessa forma, a segregação de partos poderia ser utilizada como alternativa para controlar as infecções por M. hyopneumoniae. O objetivo deste estudo foi avaliar o efeito da segregação de partos sobre a dinâmica de infecção de M. hyopneumoniae e a ocorrência e severidade das lesões pulmonares ao abate. Para isso três sistemas de produção de suínos com três sítios cada foram incluídos no estudo. A granja A consistia da unidade onde as leitoas tem o primeiro parto, ou seja, alojava somente de fêmeas de ordem de parto 1 (Granja OP1). Após o primeiro parto as fêmeas OP1 foram transferidas para a granja B (Granja OP2-6), ou seja, consistia de fêmeas de ordem de parto 2 a 6, e a granja C consistiu em uma granja convencional com reposição de leitoas (Granja OP1-6), com fêmeas de ordem de parto 1 a 6. Os leitões nascidos de cada granja foram transferidos e criados em creches e terminações segregadas. As matrizes (n = 33 (A), 37 (B), 34 (C)) de todas as granjas do estudo foram amostradas previamente ao parto e os leitões (n = 54 (A), 71 (B), 66 (C)) foram amostrados longitudinalmente aos 21, 63, 100 e 140 dias de idade e ao abate. Em todos os momentos de coleta, as amostras foram avaliadas por PCR para detecção de M. hyopneumoniae. As lesões pulmonares foram avaliadas e escores de lesão foram atribuídos ao abate. A prevalência de matrizes positivas para M. hyopneumoniae não diferiu entre as granjas (P > 0,05). A prevalência ao desmame foi maior na granja A (OP1) (P < 0,05). No entanto, dos 100 dias de idade até o abate a prevalência de leitões positivos para M. hyopneumoniae foi maior na granja B (OP2-6) (P < 0,05). A ocorrência e severidade de lesões pulmonares foram maiores na granja B. Os autores sugerem que a falta de uma aclimatação adequada das leitoas pode ter influenciado nos resultados, levando à detecção de matrizes positivas ao parto, independente da ordem de parto.

Altrenogest during early pregnancy modulates uterine glandular epithelium and endometrial growth factor expression at the time implantation in pigs

Abstract This study evaluated the effects of supplying altrenogest from day 6-12 of pregnancy on the endometrial glandular epithelium, corpora lutea (CL) morphology, and endometrial and CL gene expression. A total of 12 crossbred females (Landrace × Large White) were used. The females were assigned to 4 treatments according to a random design with a 2 × 2 factorial arrangement, with two categories (sow or gilt) and two treatments (non-treated and treated with altrenogest). On day 6 of pregnancy, animals were allocated to one of the following groups: non-treated (NT, n = 6; 3 sows and 3 gilts), and (T, n = 6; 3 sows and 3 gilts) treated daily with 20 mg of altrenogest, from day 6-12 of pregnancy. All animals were euthanized on day 13 of pregnancy. All CLs were individually weighed, and their volume were determined. The endometrial glandular density (GD), mean glandular area (MGA), and vascular density (VD) were determined by histomorphometric and immunohistochemical analyses. Endometrium samples were collected and analyzed by qRT-PCR to evaluate the abundance of transcripts for VEGF and IGF-I. Females in the T group had higher MGA (P < 0.05) compared to the NT group. There was no effect of treatment on GD or VD for both experimental groups. Sows in the T group had augmented expression of IGF-I (P < 0.05). Progestagen had no detrimental effect on CL morphology. In conclusion, altrenogest improves the uterine environment during the peri-implantation period in pigs without compromising corpora lutea development.

Altrenogest during early pregnancy modulates uterine glandular epithelium and endometrial growth factor expression at the time implantation in pigs

This study evaluated the effects of supplying altrenogest from day 6-12 of pregnancy on the endometrial glandular epithelium, corpora lutea (CL) morphology, and endometrial and CL gene expression. A total of 12 crossbred females (Landrace × Large White) were used. The females were assigned to 4 treatments according to a random design with a 2 × 2 factorial arrangement, with two categories (sow or gilt) and two treatments (non-treated and treated with altrenogest). On day 6 of pregnancy, animals were allocated to one of the following groups: non-treated (NT, n = 6; 3 sows and 3 gilts), and (T, n = 6; 3 sows and 3 gilts) treated daily with 20 mg of altrenogest, from day 6-12 of pregnancy. All animals were euthanized on day 13 of pregnancy. All CLs were individually weighed, and their volume were determined. The endometrial glandular density (GD), mean glandular area (MGA), and vascular density (VD) were determined by histomorphometric and immunohistochemical analyses. Endometrium samples were collected and analyzed by qRT-PCR to evaluate the abundance of transcripts for VEGF and IGF-I. Females in the T group had higher MGA (P < 0.05) compared to the NT group. There was no effect of treatment on GD or VD for both experimental groups. Sows in the T group had augmented expression of IGF-I (P < 0.05). Progestagen had no detrimental effect on CL morphology. In conclusion, altrenogest improves the uterine environment during the peri-implantation period in pigs without compromising corpora lutea development.(AU)

Evaporative cooling system for gestating and lactating sows: a systematic review / Sistema de resfriamento evaporativo para porcas gestantes e lactantes: uma revisão sistemática

Climatic characteristics of the production sites of pigs influence the yield of the system, with breeding sows being a category extremely sensitive to high temperatures, especially when their upper critical temperature is reached. This review evaluated the effects of the evaporative cooling system on environmental, physiological and performance parameters in breeding sows. By means of this review, a bibliographic search was performed using the following keywords: sow; swine; gilt and pig combined individually with the expression evaporative cooling. A total of 11 papers met the prerequisites determined to compose the systematic review and the studies involved gestating and lactating sows maintained in environments that presented ambient temperatures between 21.5 and 34.8 °C and relative humidity between 32.2 and 84.2%. The evaporative cooling system was used in order to cool the macro or micro environment. It can be concluded that the use of evaporative cooling system promotes increase in feed intake per lactating sow, decrease in weight loss in lactation, increase of weight of piglets at weaning, temperature reduction of the barns and decrease of the respiratory rate of the sows. For gestating sows, no changes in reproductive performance were reported.(AU)

As características climáticas dos locais de produção de suínos influenciam na produtividade do sistema, sendo as fêmeas em reprodução uma categoria extremamente sensível a elevadas temperaturas, principalmente, quando é atingida sua temperatura critica superior. Por meio desta revisão, avaliou-se os efeitos do sistema de resfriamento evaporativo sobre parâmetros ambientais, fisiológicos e de desempenho em fêmeas suínas em reprodução. Uma pesquisa bibliográfica foi realizada utilizando as palavras-chave: sow; swine; gilt e pig combinadas individualmente com a expressão evaporative cooling. Um total de 11 artigos atendeu aos pré-requisitos determinados para compor a revisão sistemática, sendo que os estudos envolveram fêmeas gestantes e lactantes mantidas em ambientes que apresentaram temperaturas entre 21,5 e 34,8 °C, e umidade relativa entre 32,2 e 84,2%. O sistema de resfriamento evaporativo foi usado de forma a resfriar o macro ou micro ambiente. Pode-se concluir que o uso do sistema de resfriamento evaporativo promove aumento do consumo de ração para porcas em lactação, diminuição da perda de peso na lactação, aumento do peso dos leitões ao desmame, redução da temperatura dos galpões e diminuição da frequência respiratória das porcas. Para porcas gestantes, não foram encontradas alterações no desempenho reprodutivo.(AU)

Phenotypic correlation of characteristics in the gilt performance test with an average number of live-born piglets through all achieved births, during the reproductive exploitation / Ligação fenotípica de características no teste de desempenho de leitões com um número médio de leitões nascidos vivos durante todos os nascimentos realizados, durante a exploração reprodutiva

Reproductive efficacy of sows dictates the level of profitability of the production itself, and the moment of testing and selection of gilts for breeding (as the parents of a future generation), represents a very important moment. Given the fact that the selection of gilts for breeding is partly based on the weight-gain in the test, in this study we examined the influence of a daily weight-gain of gilts in the test of the manifestation of important reproductive characteristics - the size of the litter of the first and the other parities, as well as the percentage of sows that gave birth in relation to previous breeding process. Data of the 11637 tested gilts that completed the performance test have been used for the test. The studied characteristics were: the weight-gain at the end of the test, the number of live-born piglets, the number of stillborn piglets and the number of grown-weaned piglets in the first litter and the total number of live-born piglets, the total number of stillborn piglets and the total number of grown-weaned piglets. The results obtained in this study showed the effect of weight-gain in the reproductive efficacy test in the number of the live-born piglets in the first and from the 2nd to the 9th parity, as well as the percentage of the sows included in the next breeding process. By including all selected independent variables that showed the adequate statistical significance in correlation with the dependent variable, the determination coefficient rises to a value of 0.098 which represents 9.80% of the influence on the dependent variable, that can be explained by the independent variable, which leads to the conclusion that the binding strength between the variable "average live" and all the independent variables: "the number of litters", the MLD depth" and "the back-fat thickness", is very weak, which is not a rare case in multiple regression.(AU)

A eficácia reprodutiva das porcas dita o nível de rentabilidade da própria produção, e o momento do teste e seleção de leitoas para reprodução (como os pais de uma geração futura) representa um momento muito importante. Dado o fato de que a seleção de leitoas para criação é parcialmente baseada no ganho de peso no teste, neste estudo examinamos a influência de um ganho de peso diário de leitoas no teste da manifestação de importantes características reprodutivas - o tamanho da ninhada da primeira e das outras paridades, assim como a porcentagem de porcas que deram à luz em relação ao processo de criação anterior. Os dados das 11637 leitoas testadas que completaram o teste de desempenho foram utilizados para o teste. As características estudadas foram: o ganho de peso ao final do teste, o número de leitões nascidos vivos, o número de leitões natimortos e o número de leitões desmamados na primeira ninhada e o número total de leitões nascidos vivos , o número total de leitões natimortos e o número total de leitões desmamados. Os resultados obtidos neste estudo mostraram o efeito do ganho de peso no teste de eficácia reprodutiva no número de leitões nascidos vivos na primeira e da segunda à nona paridade, bem como a porcentagem de porcas incluídas na próximo processo de criação. Ao incluir todas as variáveis independentes selecionadas que mostraram a significância estatística adequada em correlação com a variável dependente, o coeficiente de determinação sobe para um valor de 0.098 que representa 9.80% da influência sobre a variável dependente, que pode ser explicada pela variável independente, que leva à conclusão de que a força de ligação entre a variável "média viva" e todas as variáveis independentes: "o número de ninhadas", a profundidade MLD "e" a espessura de gordura "é muito fraca, o que não é raro caso em regressão múltipla.(AU)

Phenotypic correlation of characteristics in the gilt performance test with an average number of live-born piglets through all achieved births, during the reproductive exploitation / Ligação fenotípica de características no teste de desempenho de leitões com um número médio de leitões nascidos vivos durante todos os nascimentos realizados, durante a exploração reprodutiva

Reproductive efficacy of sows dictates the level of profitability of the production itself, and the moment of testing and selection of gilts for breeding (as the parents of a future generation), represents a very important moment. Given the fact that the selection of gilts for breeding is partly based on the weight-gain in the test, in this study we examined the influence of a daily weight-gain of gilts in the test of the manifestation of important reproductive characteristics - the size of the litter of the first and the other parities, as well as the percentage of sows that gave birth in relation to previous breeding process. Data of the 11637 tested gilts that completed the performance test have been used for the test. The studied characteristics were: the weight-gain at the end of the test, the number of live-born piglets, the number of stillborn piglets and the number of grown-weaned piglets in the first litter and the total number of live-born piglets, the total number of stillborn piglets and the total number of grown-weaned piglets. The results obtained in this study showed the effect of weight-gain in the reproductive efficacy test in the number of the live-born piglets in the first and from the 2nd to the 9th parity, as well as the percentage of the sows included in the next breeding process. By including all selected independent variables that showed the adequate statistical significance in correlation with the dependent variable, the determination coefficient rises to a value of 0.098 which represents 9.80% of the influence on the dependent variable, that can be explained by the independent variable, which leads to the conclusion that the binding strength between the variable "average live" and all the independent variables: "the number of litters", the MLD depth" and "the back-fat thickness", is very weak, which is not a rare case in multiple regression.(AU)

A eficácia reprodutiva das porcas dita o nível de rentabilidade da própria produção, e o momento do teste e seleção de leitoas para reprodução (como os pais de uma geração futura) representa um momento muito importante. Dado o fato de que a seleção de leitoas para criação é parcialmente baseada no ganho de peso no teste, neste estudo examinamos a influência de um ganho de peso diário de leitoas no teste da manifestação de importantes características reprodutivas - o tamanho da ninhada da primeira e das outras paridades, assim como a porcentagem de porcas que deram à luz em relação ao processo de criação anterior. Os dados das 11637 leitoas testadas que completaram o teste de desempenho foram utilizados para o teste. As características estudadas foram: o ganho de peso ao final do teste, o número de leitões nascidos vivos, o número de leitões natimortos e o número de leitões desmamados na primeira ninhada e o número total de leitões nascidos vivos , o número total de leitões natimortos e o número total de leitões desmamados. Os resultados obtidos neste estudo mostraram o efeito do ganho de peso no teste de eficácia reprodutiva no número de leitões nascidos vivos na primeira e da segunda à nona paridade, bem como a porcentagem de porcas incluídas na próximo processo de criação. Ao incluir todas as variáveis independentes selecionadas que mostraram a significância estatística adequada em correlação com a variável dependente, o coeficiente de determinação sobe para um valor de 0.098 que representa 9.80% da influência sobre a variável dependente, que pode ser explicada pela variável independente, que leva à conclusão de que a força de ligação entre a variável "média viva" e todas as variáveis independentes: "o número de ninhadas", a profundidade MLD "e" a espessura de gordura "é muito fraca, o que não é raro caso em regressão múltipla.(AU)

Insertion of an intrauterine catheter for post-cervical artificial insemination in gilts: a case report / Introdução do cateter intrauterino para inseminação artificial pós-cervical em leitoas: um relato de caso

The aim of this case report was to characterize the insertion of an intrauterine catheter (IC) in gilts to perform post-cervical artificial insemination (PCAI). Attempts to insert ICs through the cervixes of gilts were performed using either a standard sow foam tip catheter (SFC; n = 25) or a standard gilt foam tip catheter (GFC; n = 25). The percentage of passage, depth and degree of difficulty for insertion were evaluated. The average depth of IC insertion was 10.1 ± 1.3 cm for SFC and 10.0 ± 1.2 cm for GFC. For both catheters, insertion depths of greater than 10 cm were achieved in the first insemination in 44% of gilts. Insertion depths of greater than 6 cm were observed in 72% and 60% of attempts using SFC and GFC, respectively. A high level of difficulty for IC insertion was observed, mainly while using GFC. In conclusion, the routine application of PCAI in gilts on swine farms remains limited by the low success rate for intrauterine catheter insertion. In further studies, we suggest evaluating reproductive performance using low insertion depths for PCAI in gilts, and assessing the use of sow foam tip catheter as a guide to introduce the IC.(AU)

O objetivo deste relato de caso foi caracterizar a inserção de um cateter intrauterino (IC) em leitoas para realização da inseminação pós-cervical (PCAI). Tentativas de inserir o IC através da cérvix em leitoas foram realizadas usando um cateter de ponta de espuma padrão utilizado para porcas (SFC; n=25) e um cateter de ponta de espuma padrão utilizado para leitoas (GFC; n=25). O percentual de passagem, profundidade e grau de dificuldade para a inserção do IC através da cérvix foram avaliados. A profundidade média de inserção do IC foi 10,1 ± 1,3 cm para SFC e 10,0 ± 1,2 cm para GFC. Para ambos cateteres, profundidades maiores que 10 cm para a inserção do IC na primeira inseminação foram possíveis em 44% das leitoas. Inserções maiores que 6 cm foram observadas em 72% e 60% das tentativas utilizando SFC e GFC, respectivamente. Alto nível de dificuldade para a inserção do IC foi observada, principalmente para GFC. A aplicação da PCAI em leitoas, na rotina prática em granjas de suínos, permanece limitada pela baixa taxa de sucesso para a inserção do IC. Em estudos futuros, sugerimos o uso de menor profundidade de inserção para realizar a PCAI em leitoas e o uso de cateteres de porcas como guia para introduzir o cateter intrauterino.(AU)

Reproductive Performance, Retention Rate, and Age at the Third Parity According to Growth Rate and Age at First Mating in the Gilts with a Modern Genotype

Background: Gilts represent the largest category (18-20%) of female pigs in a breeding herd. Under field conditions, the amplitude of growth rate and age at the first mating of gilts are remarkably higher than the recommendations made by the genetic companies. There are several studies that have considered the management of these animals starting from their introduction to the herd till the mating. It has been noted that the genetic selection constantly promotes evolution that may change certain traits of these animals. However, there is a lack of the studies that evaluate the management strategies suitable for the modern sows. This study, therefore, aimed to evaluate the effect of age and growth rate of gilts at the first mating on productive performance and retention rate until the third farrowing.Materials, Methods & Results: The study was performed in a gilt development unit (GDU) with a breeding stock capacity of 1000 females and a goal of 90 gilts mating per week. The groups were retrospectively created according to age ( 210 d and 210 d) and the growth rate (GR; 700 g/d and 700 g/d) at the first mating with a 2 × 2 factorial design. A real-time ultrasound examination was performed at approximately 28 days after artificial insemination to detect pregnancy. Afterward, the productivity data over three parities of 703 females were collected and analyzed at 28 co

Appropriate level of gilt fatness and muscularity during insemination can improve the efficiency of piglet production

The aim of this study was to determine the degree of fatness and muscularity of gilts with different genotypes on the basis of intravital measurements using an Aloka SSD-500 ultrasound scanner and defining the influence of these parameters on selected indicators of reproductive performance. Research was performed on 462 gilts maintained under the same production conditions. Gilts were divided into 3 groups according to genotype: 154 Landrace gilts (L), 154 Large White (LW), 154 Landrace × Large White – [L × LW]. Four selected reproductive indicators were analyzed: the number of piglets born alive (n), average piglet birth weight (kg), number of piglets weaned at 28 days (n) and the average weaned piglet weight (kg). Our results clearly show that an appropriate level of gilt fatness during insemination can contribute to significant improvements in the efficiency of piglet production. In order to increase the number of piglets born alive, the number of piglets at weaning and the masses in these periods, it is recommended insemination of L, LW and [L × LW] gilts when their backfat thickness behind the last rib 3 cm from the midline of the spine exceeds 25 mm. In the case of backfat thickness measured 8 cm from the midline of the spine, to improve the production efficiency of these gilts it is recommended to proceed to insemination, when the value of this trait exceeds 20 mm. In addition, insemination of gilts with the genotype [L × LW] should occur when the amount of LD muscle exceeds 60 mm, the width of the muscle is greater than 135 mm, and its surface is greater than 70 cm2 .

Appropriate level of gilt fatness and muscularity during insemination can improve the efficiency of piglet production

The aim of this study was to determine the degree of fatness and muscularity of gilts with different genotypes on the basis of intravital measurements using an Aloka SSD-500 ultrasound scanner and defining the influence of these parameters on selected indicators of reproductive performance. Research was performed on 462 gilts maintained under the same production conditions. Gilts were divided into 3 groups according to genotype: 154 Landrace gilts (L), 154 Large White (LW), 154 Landrace × Large White [L × LW]. Four selected reproductive indicators were analyzed: the number of piglets born alive (n), average piglet birth weight (kg), number of piglets weaned at 28 days (n) and the average weaned piglet weight (kg). Our results clearly show that an appropriate level of gilt fatness during insemination can contribute to significant improvements in the efficiency of piglet production. In order to increase the number of piglets born alive, the number of piglets at weaning and the masses in these periods, it is recommended insemination of L, LW and [L × LW] gilts when their backfat thickness behind the last rib 3 cm from the midline of the spine exceeds 25 mm. In the case of backfat thickness measured 8 cm from the midline of the spine, to improve the production efficiency of these gilts it is recommended to proceed to insemination, when the value of this trait exceeds 20 mm. In addition, insemination of gilts with the genotype [L × LW] should occur when the amount of LD muscle exceeds 60 mm, the width of the muscle is greater than 135 mm, and its surface is greater than 70 cm2 .(AU)

Reproductive performance, retention rate, and age at the third parity according to growth rate and age at first mating in the gilts with a modern genotype

Background: Gilts represent the largest category (18-20%) of female pigs in a breeding herd. Under field conditions, the amplitude of growth rate and age at the first mating of gilts are remarkably higher than the recommendations made by the genetic companies. There are several studies that have considered the management of these animals starting from their introduction to the herd till the mating. It has been noted that the genetic selection constantly promotes evolution that may change certain traits of these animals. However, there is a lack of the studies that evaluate the management strategies suitable for the modern sows. This study, therefore, aimed to evaluate the effect of age and growth rate of gilts at the first mating on productive performance and retention rate until the third farrowing. Materials, Methods & Results: The study was performed in a gilt development unit (GDU) with a breeding stock capacity of 1000 females and a goal of 90 gilts mating per week. The groups were retrospectively created according to age ( 0.05) on farrowing rate after first, second, and third mating. The total number of piglets born in the three first farrowing and over three parities were not affected (P > 0.05) by the age and GR at first mating. The retention rate until the third farrowing of gilts inseminated with more than 210 days of age was approximately 7% greater than in the gilts mated younger; however, no statistical difference (P > 0.05) was detected. An effect of the age at the first mating was observed in the age to reach the third farrowing. Gilts mated with less than 210 and more than 210 days reached the third farrowing, respectively, at 604.5 ±1.9 and 625.1 ± 2.7 days of age (P < 0.001). Discussion: With a minimum GR of 550 g/d, 180 days of age, and at least 130 kg of weight, gilts are eligible to be inseminated without impairing their litter size, farrowing, and retention rate until the third parity. [...]

Reproductive performance, retention rate, and age at the third parity according to growth rate and age at first mating in the gilts with a modern genotype

Background: Gilts represent the largest category (18-20%) of female pigs in a breeding herd. Under field conditions, the amplitude of growth rate and age at the first mating of gilts are remarkably higher than the recommendations made by the genetic companies. There are several studies that have considered the management of these animals starting from their introduction to the herd till the mating. It has been noted that the genetic selection constantly promotes evolution that may change certain traits of these animals. However, there is a lack of the studies that evaluate the management strategies suitable for the modern sows. This study, therefore, aimed to evaluate the effect of age and growth rate of gilts at the first mating on productive performance and retention rate until the third farrowing. Materials, Methods & Results: The study was performed in a gilt development unit (GDU) with a breeding stock capacity of 1000 females and a goal of 90 gilts mating per week. The groups were retrospectively created according to age ( 0.05) on farrowing rate after first, second, and third mating. The total number of piglets born in the three first farrowing and over three parities were not affected (P > 0.05) by the age and GR at first mating. The retention rate until the third farrowing of gilts inseminated with more than 210 days of age was approximately 7% greater than in the gilts mated younger; however, no statistical difference (P > 0.05) was detected. An effect of the age at the first mating was observed in the age to reach the third farrowing. Gilts mated with less than 210 and more than 210 days reached the third farrowing, respectively, at 604.5 ±1.9 and 625.1 ± 2.7 days of age (P < 0.001). Discussion: With a minimum GR of 550 g/d, 180 days of age, and at least 130 kg of weight, gilts are eligible to be inseminated without impairing their litter size, farrowing, and retention rate until the third parity. [...](AU)

Leucine levels in low protein diets for pigs in the initial phase / Níveis de leucina em dietas com baixa proteína bruta para suínos na fase inicial

The objective of this study was to evaluate the standardized ileal digestible (SID) leucine levels in low crude protein diets on Performance, backfat thickness, longissimus dorsi depth and biochemical blood parameters of starting pigs. A total of 50 pigs, with initial weight of 11.14±0.24 kg; were distributed in a randomized blocks design with five treatments (1.10; 1.25; 1.40; 1.55 and 1.70% SID leucine), five replicates and two animals per experimental unit, comprised for a barrow and a gilt. The feed conversion ratio (FCR) reduced (P=0.018) due to the increasing SID leucine levels, without affecting other growth performance parameters (final weight, average daily feed intake, average daily gain, backfat thickness, longissimus dorsi depth and lean meat percentage). There was a quadratic effect for plasma triglyceride (P=0.049) and plasma urea (P=0.001). The optimal SID leucine levels obtained for triglycerides and urea were 1.16% and 1.24%, respectively, by associating the quadratic model with the Linear Response Plateu. Low crude protein diets with SID leucine levels up to 1.70% improved the feed conversion with desired urea and triglycerides concentration in blood plasmas achieved at 1.16% and 1.24%, respectively.

O objetivo do presente trabalho foi o de avaliar níveis de leucina digestível em dietas com baixa proteína bruta sobre o desempenho, espessura de toucinho, profundidade do músculo longissimus dorsi parâmetros sanguíneos de suínos na fase inicial. Foram utilizados 50 suínos mestiços (Landrace x Large white x Pietrain), com peso inicial de 11,14 ± 0,24 kg; distribuídos em um delineamento experimental de blocos casualizados, com cinco tratamentos (1,10; 1,25; 1,40; 1,55 e 1,70% de leucina digestível), cinco repetições e dois animais por unidade experimental, sendo um macho castrado e uma fêmea. A conversão alimentar reduziu (P=0,018) em função do aumento dos níveis de leucina digestível, sem influenciar os demais parâmetros de desempenho (peso final, consumo diário de ração, ganho de peso diário, espessura de toucinho, profundidade de lombo e porcentagem de carne magra). Com relação às variáveis plasmáticas foi observado efeito quadrático para a concentração de triglicerídeos (P=0,049) e ureia (P=0,001) em que associado ao platô do modelo Linear Response Platô (LRP) observou-se que o nível ótimo de leucina digestível para triglicerídeos e ureia foi de 1,16% e 1,24%, respectivamente. A menor concentração de ureia plasmática foi obtida ao nível de 1,24% de leucina digestível. Dietas com baixa proteína bruta e níveis de até 1,70% de leucina digestível melhoram a conversão alimentar dos suínos na fase inicial com a melhor concentração de ureia e triglicerídeos no plasma sanguíneo de 1,16% e 1,24%, respectivamente.

Performance reprodutiva de leitoas submetidas à inseminação artificial pós-cervical / Reproductive performance of gilts submitted to post-cervical artificial insemination

O objetivo deste trabalho foi avaliar o desempenho reprodutivo de nulíparas submetidas à inseminação artificial pós-cervical (IAPC) comparada à inseminação artificial tradicional (IAT). Foram avaliados ocorrência de sangramento, ocorrência de refluxo, dificuldade no transpasse da cérvix e total de células refluídas até 30 minutos após inseminação. Fêmeas submetidas à IAPC (n=279) foram inseminadas com doses de 1,5 x 109 diluídas em 45mL, e fêmeas submetidas à IAT (n=273) inseminadas com doses de 2,5 x 109 em 80mL. O transpasse da cérvix foi possível em 91,04% (254/279) das leitoas. A dificuldade no transpasse foi de 41,58% (116/279), não comprometendo o desempenho reprodutivo (P>0,05). Presença de sangramento não afetou a taxa de parto nem o número de leitões nascidos para ambos os tratamentos (P>0,05). O percentual de espermatozoides presentes no refluxo foi maior na IAT, não sendo observada diferença no tamanho de leitegada de acordo com o percentual de espermatozoides no refluxo (P>0,05) e no número de leitões nascidos totais (11,63 e 11,81) entre os tratamentos IAT e IAPC, respectivamente. Pode-se realizar IAPC em leitoas sem causar redução no desempenho, utilizando-se doses com 1,5 x 109 células espermáticas.(AU)

The objective of this study was to evaluate the reproductive performance of gilts subjected to post-cervical artificial insemination (PCAI) compared to traditional artificial insemination (TAI). We also evaluated the degree of difficulty in bypassing the cervix, time required to perform the insemination, presence of bleeding after insemination, semen backflow, as well as the volume and the total reflow cells 30 minutes after insemination. Gilts submitted to PCAI (n = 279) were inseminated with 45 mL doses of 1.5 x 109 sperm cells and the ones submitted to TAI (n = 273) were inseminated with 80 mL doses with 2.5 x 109 cells. The bypassing of the cervix was possible in 91.04% (254/279) of gilts. The difficulty bypassing the cervix in at least one of the gilt's PCAI procedures happened with 41.58% (116/279) of the females, but it did not affect reproductive performance (P>0.05). The presence of bleeding after insemination did not affect the farrowing rate and total number of piglets born for both treatments (P>0.05). The average time needed to carry out the PCAI was 1.47 minutes and the TAI was 4.04 minutes. The percentage of sperm present in the reflux was higher in TAI than the PCAI, but no correlation was found between litter size and the percentage of sperm in reflux (P>0.05) and the total number of piglets born (11.63 and 11.81) between TAI and PCAI treatments, respectively. Thus, it is possible to perform the post-cervical artificial insemination in gilts without causing a reduction in reproductive performance, using doses with a concentration of 1.5 x 109 sperm cells.(AU)

Performance reprodutiva de leitoas submetidas à inseminação artificial pós-cervical / Reproductive performance of gilts submitted to post-cervical artificial insemination

O objetivo deste trabalho foi avaliar o desempenho reprodutivo de nulíparas submetidas à inseminação artificial pós-cervical (IAPC) comparada à inseminação artificial tradicional (IAT). Foram avaliados ocorrência de sangramento, ocorrência de refluxo, dificuldade no transpasse da cérvix e total de células refluídas até 30 minutos após inseminação. Fêmeas submetidas à IAPC (n=279) foram inseminadas com doses de 1,5 x 109 diluídas em 45mL, e fêmeas submetidas à IAT (n=273) inseminadas com doses de 2,5 x 109 em 80mL. O transpasse da cérvix foi possível em 91,04% (254/279) das leitoas. A dificuldade no transpasse foi de 41,58% (116/279), não comprometendo o desempenho reprodutivo (P>0,05). Presença de sangramento não afetou a taxa de parto nem o número de leitões nascidos para ambos os tratamentos (P>0,05). O percentual de espermatozoides presentes no refluxo foi maior na IAT, não sendo observada diferença no tamanho de leitegada de acordo com o percentual de espermatozoides no refluxo (P>0,05) e no número de leitões nascidos totais (11,63 e 11,81) entre os tratamentos IAT e IAPC, respectivamente. Pode-se realizar IAPC em leitoas sem causar redução no desempenho, utilizando-se doses com 1,5 x 109 células espermáticas.(AU)

The objective of this study was to evaluate the reproductive performance of gilts subjected to post-cervical artificial insemination (PCAI) compared to traditional artificial insemination (TAI). We also evaluated the degree of difficulty in bypassing the cervix, time required to perform the insemination, presence of bleeding after insemination, semen backflow, as well as the volume and the total reflow cells 30 minutes after insemination. Gilts submitted to PCAI (n = 279) were inseminated with 45 mL doses of 1.5 x 109 sperm cells and the ones submitted to TAI (n = 273) were inseminated with 80 mL doses with 2.5 x 109 cells. The bypassing of the cervix was possible in 91.04% (254/279) of gilts. The difficulty bypassing the cervix in at least one of the gilt's PCAI procedures happened with 41.58% (116/279) of the females, but it did not affect reproductive performance (P>0.05). The presence of bleeding after insemination did not affect the farrowing rate and total number of piglets born for both treatments (P>0.05). The average time needed to carry out the PCAI was 1.47 minutes and the TAI was 4.04 minutes. The percentage of sperm present in the reflux was higher in TAI than the PCAI, but no correlation was found between litter size and the percentage of sperm in reflux (P>0.05) and the total number of piglets born (11.63 and 11.81) between TAI and PCAI treatments, respectively. Thus, it is possible to perform the post-cervical artificial insemination in gilts without causing a reduction in reproductive performance, using doses with a concentration of 1.5 x 109 sperm cells.(AU)

Leucine levels in low protein diets for pigs in the initial phase / Níveis de leucina em dietas com baixa proteína bruta para suínos na fase inicial

The objective of this study was to evaluate the standardized ileal digestible (SID) leucine levels in low crude protein diets on Performance, backfat thickness, longissimus dorsi depth and biochemical blood parameters of starting pigs. A total of 50 pigs, with initial weight of 11.14±0.24 kg; were distributed in a randomized blocks design with five treatments (1.10; 1.25; 1.40; 1.55 and 1.70% SID leucine), five replicates and two animals per experimental unit, comprised for a barrow and a gilt. The feed conversion ratio (FCR) reduced (P=0.018) due to the increasing SID leucine levels, without affecting other growth performance parameters (final weight, average daily feed intake, average daily gain, backfat thickness, longissimus dorsi depth and lean meat percentage). There was a quadratic effect for plasma triglyceride (P=0.049) and plasma urea (P=0.001). The optimal SID leucine levels obtained for triglycerides and urea were 1.16% and 1.24%, respectively, by associating the quadratic model with the Linear Response Plateu. Low crude protein diets with SID leucine levels up to 1.70% improved the feed conversion with desired urea and triglycerides concentration in blood plasmas achieved at 1.16% and 1.24%, respectively.(AU)

O objetivo do presente trabalho foi o de avaliar níveis de leucina digestível em dietas com baixa proteína bruta sobre o desempenho, espessura de toucinho, profundidade do músculo longissimus dorsi parâmetros sanguíneos de suínos na fase inicial. Foram utilizados 50 suínos mestiços (Landrace x Large white x Pietrain), com peso inicial de 11,14 ± 0,24 kg; distribuídos em um delineamento experimental de blocos casualizados, com cinco tratamentos (1,10; 1,25; 1,40; 1,55 e 1,70% de leucina digestível), cinco repetições e dois animais por unidade experimental, sendo um macho castrado e uma fêmea. A conversão alimentar reduziu (P=0,018) em função do aumento dos níveis de leucina digestível, sem influenciar os demais parâmetros de desempenho (peso final, consumo diário de ração, ganho de peso diário, espessura de toucinho, profundidade de lombo e porcentagem de carne magra). Com relação às variáveis plasmáticas foi observado efeito quadrático para a concentração de triglicerídeos (P=0,049) e ureia (P=0,001) em que associado ao platô do modelo Linear Response Platô (LRP) observou-se que o nível ótimo de leucina digestível para triglicerídeos e ureia foi de 1,16% e 1,24%, respectivamente. A menor concentração de ureia plasmática foi obtida ao nível de 1,24% de leucina digestível. Dietas com baixa proteína bruta e níveis de até 1,70% de leucina digestível melhoram a conversão alimentar dos suínos na fase inicial com a melhor concentração de ureia e triglicerídeos no plasma sanguíneo de 1,16% e 1,24%, respectivamente.(AU)