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.

Effects of lowering dietary protein content without or with increased protein-bound and feed-grade amino acids supply on growth performance, body composition, metabolism, and acute-phase protein of finishing pigs under daily cyclic heat stress.

This study investigated the effects of a low-protein diet with or without an increase in dietary protein and feed-grade amino acids (AAs) on the growth performance, body composition, metabolism, and serum acute-phase proteins of finishing pigs reared in thermoneutrality or cyclic heat stress conditions. A total of 90 gilts (67.7 ± 6.2 kg) were distributed in a 2 × 3 factorial arrangement (two ambient temperatures and three diets). Ambient temperatures (AT) were thermoneutral (TN, 22 °C for 24 h) and cyclic heat stress (CHS, 12 h to 35 °C and 12 h to 22 °C). The evaluated diets (D) were high crude protein (HP); low CP-free AA-supplemented diets (LPAAs); low CP-free AA-supplemented diets and digestible Lys level (+20%), and Lys:AA ratios above recommendations (LPAA+). The experimental period lasted 48 d (two experimental phases: days 0-27 and days 28-48, respectively). CHS pigs had higher skin temperature (P < 0.05) than TN pigs. Pigs in CHS had higher rectal temperature (P < 0.05) than TN pigs until day 38 but similar (P > 0.10) to TN pigs from 38 to 45 d. For the entire experiment, CHS pigs had lower (P < 0.05) final BW, average daily gain and daily feed intake, net energy intake, body lipid, bone mineral, lipid deposition, energy retention, Lys and CP intake, and nitrogen excretion than TN pigs. The level of CP intake impacted nitrogen excretion, nitrogen retention efficiency, and urea as pigs fed HP had the highest values, and pigs fed LPAA had the lowest values (P < 0.05). On day 27, CHS pigs had lower (P < 0.05) free triiodothyronine than TN pigs. LPAA+ pigs had lower (P < 0.05) insulin than LPAA. On day 48, CHS pigs had lower (P < 0.05) thyroxine, albumin, and lactate than TN pigs. On day 27, pigs fed LPAA+ had higher (P < 0.05) lactate than pigs fed HP or LPAA. Both AT and D were enough to stimulate the immune system as CHS pigs had lower (P < 0.05) transferrin and 23-kDa protein levels than TN pigs, and HP pigs had higher haptoglobin than LPAA on day 27. These results confirm the deleterious effects of high AT on performance, body composition, metabolism, and immune system stimulation in finishing pigs. These data also show that a diet with low levels of CP can be provided to pigs in CHS without affecting performance and body composition while reducing nitrogen excretion. However, the use of a diet with an AA level above the requirements obtained by increasing intact protein and free AA did not attenuate the impact of CHS on performance and body composition of pigs.

High ambient temperature and air humidity are the most important climatic factors that jeopardize pig production. Multiple strategies can be applied for pigs under heat stress, including recent research to improve understanding the use of nutrition to attenuate the impact of heat stress. Heat stress impairs digestion, absorption, and amino acid metabolism with changes in amino acid requirements. Updates on the nutritional assessment strategies by differing the diets by protein and amino acid content (protein-bound or feed-grade) seem to be efficient tools for pork producers as amino acids play a functional role in challenged pigs apart from the beneficial effects on performance.

The effect of gilt flow management during acclimation on Mycoplasma hyopneumoniae detection.

The objective of this study was to characterize the Mycoplasma hyopneumoniae (M. hyopneumoniae) detection and seroconversion patterns in recently acclimated gilts to be introduced to endemically infected farms using different types of replacement management. Three gilt developing units (GDUs) belonging to sow farms were included in this investigation: two farms managed gilts in continuous flow, and one farm managed gilts all-in/all-out. Two replicates of 35 gilts each were selected per GDU and sampled approximately every 60 days for a total of four or five samplings, per replicate and per GDU. Detection of M. hyopneumoniae was evaluated by PCR, while antibodies were measured using a commercial ELISA assay. Also, M. hyopneumoniae genetic variability was evaluated using Multiple-Locus Variable number tandem repeat Analysis. Detection of M. hyopneumoniae was similar across GDUs. Although a significant proportion of gilts was detected positive for M. hyopneumoniae after acclimation, an average of 30.3 % of gilts was negative at any point during the study. Detection of M. hyopneumoniae antibodies was similar among GDUs regardless of flow type or vaccination protocol. The genetic variability analysis revealed a limited number of M. hyopneumoniae types within each GDU. Results of this study showed a similar pattern of M. hyopneumoniae detection by PCR and seroconversion by ELISA among GDUs, regardless of the type of flow management strategies applied to gilts.

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)

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)

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)

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

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 ( 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

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

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

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

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

Efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas em terminação / Effects of ractopamine and two lysine levels on performance and carcass traits of gilts in the finishing phase

Avaliaram-se os efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas com peso corporal a partir de 85kg, durante 21 e 28 dias antes do abate, os quais foram distribuídos em delineamento experimental de blocos ao acaso com cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de arranjo fatorial 2x2, com dois níveis de lisina digestível (LD), 0,67 e 0,87 por cento, e dois níveis de ractopamina (0 e 5ppm). Observou-se efeito significativo do nível de LD sobre o ganho de peso e peso corporal e interação significativa (P<0,05) entre o nível de LD e a ractopamina sobre a conversão alimentar e sobre a taxa de deposição de carne magra corporal. Não houve efeito significativo (P>0,05) do nível de LD sobre a espessura de toucinho, profundidade de lombo e rendimento em carne magra da carcaça de acordo com avaliação da carcaça, feita in vivo. Não houve efeito (P>0,05) da ractopamina sobre o consumo de ração, o ganho de peso diário e o peso corporal aos 21 e 28 dias de experimento. A ractopamina reduziu a espessura de toucinho no ponto P2 aos 21 dias e aumentou o rendimento de carne magra e a profundidade de lombo na avaliação da carcaça no frigorífico.(AU)

The effects of ractopamine and digestible lysine levels on performance and carcass traits of gilts with initial body weight average of 85kg, recorded during 21 and 28 day before slaughtering time were evaluated in a completely randomized block design with five replicates of two animals per experiment unit. The treatments consisted in a 2 x 2 factorial scheme, two levels of digestible lysine (DL) (0.67 and 0.87 percent) and two ractopamine levels (0 and 5ppm). Significant effects of DL on daily weight gain and body weight and significant effects of DL and ractopamine level were observed for feed:weight gain ratio and lean meat carcass deposition. No significant effects (P>0.05) of DL on fat thickness, muscle depth and lean meat yield according to the in vivo carcass evaluation were observed. No significant effect of ractopamine (P>0.05) on feed intake, daily weight gain and body weight (21 and 28 days) were observed. Ractopamine reduced back fat thickness at P2 point (21days) and increased lean meat yield and muscle depth in frigorific carcass evaluation.(AU)

Efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas em terminação / Effects of ractopamine and two lysine levels on performance and carcass traits of gilts in the finishing phase

Avaliaram-se os efeitos da ractopamina e de dois níveis de lisina digestível na dieta sobre o desempenho e características de carcaça de leitoas com peso corporal a partir de 85kg, durante 21 e 28 dias antes do abate, os quais foram distribuídos em delineamento experimental de blocos ao acaso com cinco repetições de dois animais por unidade experimental. Os tratamentos consistiram de arranjo fatorial 2x2, com dois níveis de lisina digestível (LD), 0,67 e 0,87 por cento, e dois níveis de ractopamina (0 e 5ppm). Observou-se efeito significativo do nível de LD sobre o ganho de peso e peso corporal e interação significativa (P<0,05) entre o nível de LD e a ractopamina sobre a conversão alimentar e sobre a taxa de deposição de carne magra corporal. Não houve efeito significativo (P>0,05) do nível de LD sobre a espessura de toucinho, profundidade de lombo e rendimento em carne magra da carcaça de acordo com avaliação da carcaça, feita in vivo. Não houve efeito (P>0,05) da ractopamina sobre o consumo de ração, o ganho de peso diário e o peso corporal aos 21 e 28 dias de experimento. A ractopamina reduziu a espessura de toucinho no ponto P2 aos 21 dias e aumentou o rendimento de carne magra e a profundidade de lombo na avaliação da carcaça no frigorífico.

The effects of ractopamine and digestible lysine levels on performance and carcass traits of gilts with initial body weight average of 85kg, recorded during 21 and 28 day before slaughtering time were evaluated in a completely randomized block design with five replicates of two animals per experiment unit. The treatments consisted in a 2 x 2 factorial scheme, two levels of digestible lysine (DL) (0.67 and 0.87 percent) and two ractopamine levels (0 and 5ppm). Significant effects of DL on daily weight gain and body weight and significant effects of DL and ractopamine level were observed for feed:weight gain ratio and lean meat carcass deposition. No significant effects (P>0.05) of DL on fat thickness, muscle depth and lean meat yield according to the in vivo carcass evaluation were observed. No significant effect of ractopamine (P>0.05) on feed intake, daily weight gain and body weight (21 and 28 days) were observed. Ractopamine reduced back fat thickness at P2 point (21days) and increased lean meat yield and muscle depth in frigorific carcass evaluation.

Indução da puberdade e sincronização do cio subsequente em leitoas pré-púberes utilizando gonadotrofinas exógenas / Induction of puberty and following estrus synchronization in prepubertal gilts using exogenous gonadotropins

A utilização de gonadotrofinas exógenas na indução da puberdade e sincronização do estro e ovulação é uma prática que influencia positivamente no manejo das marrãs, para a mais efetiva e econômica inclusão no plantel de matrizes em Sistemas Intensivos de Produção de Suínos. No entanto, poucos estudos têm sido desenvolvidos com a finalidade de avaliar o grau de sincronização do estro seguinte à indução da puberdade. Assim sendo, o objetivo do presente estudo foi, justamente, o de verificar a taxa de sincronização do estro subseqüente à puberdade induzida hormonalmente, e a comparação das características dos estros, induzido e subseqüente a este. Sessenta e seis leitoas pré-púberes tiveram a puberdade induzida através de combinação hormonal utilizando gonadotrofinas (eCG e LH) aos 145 dias de idade em média. Das 66 fêmeas que iniciaram o experimento, 35 (53,03%) apresentaram cio até sete dias após a aplicação do LH, e 40 (60,60%) das 66 fêmeas tiveram o estro subseqüente sincronizado, ou seja, até o 25° dia após a aplicação do LH. Vinte e seis (39,39%) fêmeas manifestaram o primeiro e segundo cios. As 26 (39,39%) leitoas que não manifestaram o 2° cio de maneira sincronizada foram abatidas, sendo que 15 apresentaram corpos lúteos e/ou corpos albicans e 11 não apresentaram as estruturas mencionadas anteriormente, sendo consideradas imaturas. Não houve diferença significativa da duração do cio na puberdade com o cio subseqüente (P>0,05), tampouco da dispersão dos mesmos.(AU)

The utilization of exogenous gonadotropins in the puberty induction and estrus/ovulation synchronization is a management that influence positive1y gilts handle, to the better effectiveness and economic inclusion of gilts in the Intensive Swine Production System herd. However, few researches have been deve10ped to evaluate the subsequent estrus synchronization after puberty induction. Thus, the aim of this study was to verify the subsequent estrus synchronization after the hormonal puberty induction and to evaluate the inducted and the following one estrus characteristics. Sixty six prepubertal gilts had their puberty inducted by a hormonal combination using gonadotropins (eCG and LH) at 145 days old, in average. A total of 35 (52,03%) of the 66 initially gilts showed estrus up to seven days after LH administration, and 40 (60,60%) had the subsequent estrus synchronized (synchronization was defined as the gilts which showed estrus up to day 25 after LH administration). Twenty six gilts (39,39%) showed the first and second estrus. The 26 (39,39%) remaining gilts that didn't show the second estrus synchronized were slaughtered, which 15 presented corpus albicans and/or corpora lutea and 11 were considered immature because they didn't present any structure mentioned above in the ovaries. There was no significant difference between the puberty estrus duration and the subsequent estrus duration (P>0,05), neither their dispersion.(AU)

Desempenho produtivo de leitoas alimentadas com dietas de gestação de baixo ou alto nível de casca de soja

Gilts were fed gestation diets, with inclusion of 7% (T1) and 35% (T2) of soybean hulls which had fiber levels of 4.5 and 13.1%, respectively. After insemination, all females received 1.8kg of T1 diet (5470Kcal ME day-1) up to 35 days of gestation, when they were allocated to receive 2.4kg (7294Kcal ME day-1) of T1 (n= 108) or 2.7kg (7249Kcal ME day-1) of T2 (n= 99) diet. At 90 days of gestation T1 and T2 females started to receive 3.0kg (9117Kcal ME day-1) and 3.4kg (9129Kcal ME day-1) of T1 and T2 diets, respectively. The T1 females were heavier than T2 females, at 110 days of gestation and at parturition (P 0.05). However, the daily average feed intake during lactation was 5.3% higher for T2 (P=0.01) than for T1 females. There was no effect of treatments on milk production and composition, weight variation during lactation and weaning-to-estrus interval (P>0.05). Treatments were similar for total and born alive litter size, stillborn and mummified (P>0.05). The average birth weight was higher for T1 piglets (P=0.03), but litter weight was similar for treatments (P>0.05). Weaned litter size and weight did not differ for treatments (P>0.05). The two levels of soybean hulls in the gestation diets of gilts resulted in similar performance.

Leitoas foram alimentadas com dietas de gestação com inclusão de 7% (T1) e 35% (T2) de casca de soja, as quais continham níveis de 4,5 e 13,1% de fibra bruta, respectivamente. Após a inseminação, todas as fêmeas receberam 1,8kg da ração T1 (5470Kcal EM dia-1) até os 35 dias de gestação, quando foram separadas em dois grupos que receberam 2,4kg (7294Kcal EM dia-1) da ração T1 (n=108) ou 2,7kg (7249Kcal EM dia-1) da ração T2 (n=99). Aos 90 dias de gestação, as fêmeas T1 e T2 receberam respectivamente 3,0kg (9117Kcal EM dia-1) e 3,4kg (9129Kcal EM dia-1) de ração. As fêmeas T1 foram mais pesadas que as T2 aos 110 dias de gestação e ao parto (P 0,05). No entanto, o consumo diário médio de ração durante a lactação foi 5,3% maior para as fêmeas T2 (P=0,01) do que para as fêmeas T1. Não houve efeito dos tratamentos sobre a produção e composição do leite, a variação de peso das fêmeas durante a lactação e o intervalo desmame-estro (P>0,05). O número de nascidos totais, nascidos vivos, natimortos e mumificados foi semelhante (P>0,05) entre os tratamentos. O peso médio ao nascer foi maior (P=0,03) para os leitões das fêmeas T1, mas não houve diferença entre os tratamentos no peso médio da leitegada (P>0,05). O peso e número de leitões ao desmame não foram afetados pelos tratamentos (P>0,05). Os dois níveis de inclusão de casca de soja na dieta de gestação de leitoas resultaram em desempenho produtivo semelhante.

Desempenho produtivo de leitoas alimentadas com dietas de gestação de baixo ou alto nível de casca de soja

Gilts were fed gestation diets, with inclusion of 7% (T1) and 35% (T2) of soybean hulls which had fiber levels of 4.5 and 13.1%, respectively. After insemination, all females received 1.8kg of T1 diet (5470Kcal ME day-1) up to 35 days of gestation, when they were allocated to receive 2.4kg (7294Kcal ME day-1) of T1 (n= 108) or 2.7kg (7249Kcal ME day-1) of T2 (n= 99) diet. At 90 days of gestation T1 and T2 females started to receive 3.0kg (9117Kcal ME day-1) and 3.4kg (9129Kcal ME day-1) of T1 and T2 diets, respectively. The T1 females were heavier than T2 females, at 110 days of gestation and at parturition (P 0.05). However, the daily average feed intake during lactation was 5.3% higher for T2 (P=0.01) than for T1 females. There was no effect of treatments on milk production and composition, weight variation during lactation and weaning-to-estrus interval (P>0.05). Treatments were similar for total and born alive litter size, stillborn and mummified (P>0.05). The average birth weight was higher for T1 piglets (P=0.03), but litter weight was similar for treatments (P>0.05). Weaned litter size and weight did not differ for treatments (P>0.05). The two levels of soybean hulls in the gestation diets of gilts resulted in similar performance.

Leitoas foram alimentadas com dietas de gestação com inclusão de 7% (T1) e 35% (T2) de casca de soja, as quais continham níveis de 4,5 e 13,1% de fibra bruta, respectivamente. Após a inseminação, todas as fêmeas receberam 1,8kg da ração T1 (5470Kcal EM dia-1) até os 35 dias de gestação, quando foram separadas em dois grupos que receberam 2,4kg (7294Kcal EM dia-1) da ração T1 (n=108) ou 2,7kg (7249Kcal EM dia-1) da ração T2 (n=99). Aos 90 dias de gestação, as fêmeas T1 e T2 receberam respectivamente 3,0kg (9117Kcal EM dia-1) e 3,4kg (9129Kcal EM dia-1) de ração. As fêmeas T1 foram mais pesadas que as T2 aos 110 dias de gestação e ao parto (P 0,05). No entanto, o consumo diário médio de ração durante a lactação foi 5,3% maior para as fêmeas T2 (P=0,01) do que para as fêmeas T1. Não houve efeito dos tratamentos sobre a produção e composição do leite, a variação de peso das fêmeas durante a lactação e o intervalo desmame-estro (P>0,05). O número de nascidos totais, nascidos vivos, natimortos e mumificados foi semelhante (P>0,05) entre os tratamentos. O peso médio ao nascer foi maior (P=0,03) para os leitões das fêmeas T1, mas não houve diferença entre os tratamentos no peso médio da leitegada (P>0,05). O peso e número de leitões ao desmame não foram afetados pelos tratamentos (P>0,05). Os dois níveis de inclusão de casca de soja na dieta de gestação de leitoas resultaram em desempenho produtivo semelhante.

Serum concentrations of creatine kinase and of triglycerides during lactation in gilts bred older and in multiparous sows fed ad libitum

The aim of this paper was to assess the possible variation in blood concentrations of creatine kinase (CK) and triglycerides in gilts bred older in comparison with multiparous sows. Ten primiparous and ten Camborough multiparous sows from the fourth to seventh parities were used. Breeding age and weight of gilts averaged respectively 231 days and 149.5kg. All females were moved into individual farrowing crates and were managed under the same conditions. Blood samples were collected by puncturing the coccygeal artery on day 7 before expected farrowing, and on days 2, 7, 14, 21 of lactation and 2 days after weaning. No difference in triglycerides and CK serum concentrations between groups were observed. The CK levels were low before farrowing, increased substantially on days 2 and 7 and decreased toward the end of lactation. The concentrations of triglycerides were slightly high before the parturition, diminished on days 2, 7, 14 and 21 and increased after weaning.

O objetivo deste trabalho foi verificar as possíveis variações na concentração sangüínea de CK e de triglicérides em porcas primíparas cobertas tardiamente, em comparação com porcas multíparas. Foram utilizadas dez porcas primíparas e dez multíparas, com ordem de parição entre 5 e 7 anos, todas da linhagem Camborough. A cobrição efetiva das leitoas ocorreu na idade média de 231 dias, com 149,5kg. Todas as fêmeas foram alojadas em gaiolas individuais de parição e mantidas sob as mesmas condições. As amostras de sangue foram colhidas por punção da artéria coccígea 7 dias antes do parto previsto, nos dias 2, 7, 14 e 21 de lactação e 2 dias após o desmame. Não foi observada diferença significativa na concentração sérica de CK e de triglicérides entre os dois grupos. A concentração de CK foi baixa antes do parto, elevou-se substancialmente nos dias 2 e 7 de lactação e decresceu progressivamente até o final da lactação. A concentração de triglicérides foi ligeiramente maior antes do parto, diminuindo nos dias 2, 7, 14 e 21 da lactação, voltando a elevar-se após a desmama.