Effect of birth weight and litter size on the performance of landrace gilts until puberty

Background: The selection for larger litter size has resulted in reduction of average birth weight and in increase of withinlitter birth weight variation in pigs. Birth weight is one of the most important factors affecting the survival and performance of piglets until weaning. The aim of this study was to evaluate the effect of litter size into which gilts were born and their individual birth weight on mortality and culling rate until the time of selection, as well as on puberty onset. Materials, Methods & Results: Female Landrace piglets (n = 1525) were identifi ed and weighed within 18 h after birth. They were also weighed at weaning (n = 1379), and at the end of the nursery (n = 1198) and rearing phases (n = 940). Three classes of litter size were created: Small LS (7-11 piglets), Intermediate LS (12-13 piglets) and Large LS (14-19 piglets). Gilts were also separated in three classes according to their birth weight: Low BW (530-1200 g), Intermediate BW (1205-1600 g) and High BW (1605-2535 g). When compared to High BW gilts, the risk of death until weaning was greater (P 0.05). The risk of not being selected for breeding was greater (P 0.05). Discussion: The importance of birth weight for survival until weaning and for development until the selection time was confi rmed in this study. Since birth weight was associated with ADWG, the expectation was that puberty onset would happen earlier in gilts with greater ADWG. In other studies, gilts with greater growth rates reached puberty earlier if stimulated at an early age (~140 days of age). In the present study, however, puberty onset was not affected by birth weight, probably because gilts were exposed to boars at 165 days of age. This aspect may indicate that, after a certain age, puberty is less dependent on growth rate. The greater risk of mortality until weaning and of not being selected for reproduction, in Light BW gilts, contribute to economic losses in replacement gilt units. Segregation of gilts based on their birth weight can be performed at birth or in subsequent phases. Early selection may help to reduce costs for maintaining gilts that will probably not be selected, hence increasing the profi tability of pig production. In addition, it provides the opportunity to pay special attention to gilts with greater potential to be future breeders. The results show that birth weight is more important than litter size into which gilts were born for their survival until weaning, as well as for an adequate weight gain, which will ensure their retention in the herd until the selection time. When the gilts are stimulated close to 165 days of age, age at puberty and anoestrous rate are not affected by birth weight or litter size into which they were born

Caracterização do momento da morte fetal em suínos a partir do tamanho dos mumificados

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Mumificação fetal na suinocultura moderna : importância e fatores de riscos

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Existe diferença no desempenho reprodutivo ao primeiro...

O grupo de leitoas representa o maior porcentual de fêmeas dentro de uma granja produtora de suínos e aquelas fêmeas que apresentarem um maior número de nascidos no primeiro parto tendem a ter um maior número de nascidos durante a vida. As principais recomendações quanto ao momento da primeira cobertura levam em consideração a idade, o peso, a espessura de toucinho e o número de estros. Foram selecionadas 613 leitoas inseminadas do 1º ao 4º estro apresentado a partir dos 185 dias de idade. No momento da cobertura todas as fêmeas foram pesadas e foi realizada a medição da espessura de toucinho no P2.  As idades e os pesos médios no momento da primeira cobertura não diferiram entre os 4 grupos. As leitoas cobertas no 1º estro apresentaram menor tamanho de leitegada (10,1; 11,7; 12,1 e 12,4, respectivamente) e menor taxa de parto (68,9%; 86,5%; 88,2% e 92,0%, respectivamente) comparado às fêmeas cobertas no 2º, 3º e 4º estro (

Perspectivas de aplicabilidade da inseminação artificial intrauterina em leitoas

The application of the intrauterine artificial insemination (IUAI) technique allows optimization of a swine production system due to the reductions in volume and number of sperm cells in the insemination dose, and by reducing the time taken to perform the insemination. However, IUAI is not recommended for gilts due to the difficulty of intrauterine cannula passage through the cervix. This difficulty is associated mainly with the fact that the reproductive tract is smaller in gilts than in pluriparous females. However, few studies have evaluated the application of IUAI in gilts. In these studies, there are variations in approach concerning the definition of the success rate for cannula passage through the cervix, the type of cannula and the body characteristics of the gilts used, making it difficult to extrapolate the recommendation for the use of IUAI in gilts. Considering the evidence that such characteristics influence or even determine the success of the application of IUAI, there is a necessity for an understanding of the influence of these factors in the improvement and later application of the technique. Gilts represent about 15–20% of the breeding group, and the use of IUAI could optimize the processes of insemination on farms. The approach used in this review highlights the aspects that could aid in structuring further studies for improving IUAI in gilts, allowing its use on commercial farms.A aplicação da técnica de inseminação artificial intrauterina (IAU) permitiu uma otimização do sistema de produção de suínos por possibilitar a redução do volume e número de células espermáticas na dose inseminante e, também, por diminuir o tempo de execução da inseminação. Porém, a IAU não tem sido recomendada para leitoas devido à dificuldade de passagem do cateter intrauterino através da cérvix. Essa dificuldade é associada principalmente ao menor tamanho do trato reprodutivo de leitoas se comparado ao das fêmeas pluríparas. Entretanto, ainda são poucos os estudos que avaliaram a aplicação de IAU em leitoas. Nesses estudos, existem variações quanto à definição da taxa de sucesso na inserção do cateter através da cérvix, ao tipo de cateter e, também, quanto às características corporais das matrizes utilizadas, dificultando extrapolações de recomendação do uso da IAU em leitoas. Considerando os indícios de que tais características podem influenciar ou, até mesmo, determinar o sucesso de aplicação da técnica, ainda há necessidade de compreender a influência desses fatores para que a técnica possa ser aprimorada e posteriormente aplicada. Leitoas representam cerca de 15 a 20% do grupo de cobertura e viabilizar a IAU nessa categoria pode otimizar os processos de inseminação nas granjas. A abordagem realizada nessa revisão traz aspectos que podem auxiliar na estruturação de futuros estudos para aprimorar a IAU em leitoas e permitir seu emprego em granjas comerciais

Desempenho produtivo de um rebanho caprino no município de Barra do Ribeiro, RS

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Sincronização de cio em cabras com uso de ecg fora da estação reprodutiva

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Uso de tônus e ecogenicidade testiculares na identificação de reprodutores suínos com baixa qualidade espermática

This study aimed to evaluate the use of some testicular traits to identify boars with low sperm morphological quality. The consistency (scores from 1 to 5), tone with tonometry (mm), parenchyma echogenicity and heterogeneity with ultrasound (pixel) were assessed in 402 mature boars (18.5 months on average). Sperm abnormality thresholds (≤ 25% of total sperm abnormalities, ≤ 5% of heads, acrosome, neck or midpiece defects, ≤ 10% tail defects, and 15% cytoplasmic droplets) were used to classify boars as approved or disapproved. Three classes of testicular traits were formed (extremely low and high values, approximately 15% each, were kept in separated classes). When the traits were individually evaluated, fewer boars were approved if the echogenicity or heterogeneity were high, or if the tone was rigid. When evaluated in combination, the interaction between heterogeneity and tone, and between heterogeneity and echogenicity were significant. The high heterogeneity combined with soft tone or with hypo-echogenicity resulted in lower approval of boars. Tonometry and ultrasonography have a moderate potential to be included in breeding soundness examination of boars. When combined, they provide more reliable information about the impact of testicular parenchymal alterations on morphology of sperm cells.O estudo objetivou avaliar o uso de características testiculares para identificar reprodutores com baixa qualidade de morfologia espermática. A consistência (escore de 1 a 5), o tônus por tonometria (mm), a ecogenicidade e a heterogeneidade do parênquima testicular por ultrassonografia (pixel) foram avaliados em 402 machos suínos maduros (18,5 meses, em média). Limiares máximos de anormalidades espermáticas (≤ 25% de defeitos totais, ≤ 5% de defeitos de cabeça, acrossoma, colo e peça intermediária, ≤ 10% de defeitos de cauda e 15% de gota citoplasmática) foram utilizados para classificar os machos como aprovados ou reprovados. Três classes de características testiculares foram formadas (valores extremamente baixos e altos, aproximadamente 15% em cada, foram mantidos em classes separadas). Quando as características testiculares foram avaliadas individualmente, menos machos foram aprovados se a ecogenicidade ou a heterogeneidade foram altas, ou se o tônus era rígido. Quando avaliadas em combinação, a interação entre heterogeneidade e tônus e a interação entre heterogeneidade e ecogenicidade foram significativas. A alta heterogeneidade combinada com testículos flácidos ou com testículos hipoecogênicos resultou em menor aprovação de cachaços. A tonometria e a ultrassonografia possuem potencial moderado para serem incluídas no exame andrológico de cachaços. Quando combinadas, as técnicas fornecem uma informação mais consistente do impacto das alterações do parênquima testicular na morfologia das células espermáticas

Natimortalidade na suinocultura moderna : importância e fatores de riscos

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Effect of different systems for the control of environmental temperature on the performance of sows and their litters

Background: In tropical and subtropical regions, temperature values above thermoneutrality for pigs are often experienced and lactating sows maintained outside the thermal comfort zone might have their performance compromised. The use of ventilation or evaporative cooling to maintain animal thermoregulation might be alternatives to minimise animal production losses. The objective of this study was to evaluate the infl uence of three different systems for the control of environmental temperature on the productivity of sows and their litters. Materials, Methods & Results: Three systems of environmental temperature control were evaluated: air-conditioned: AC (n = 79), with farrowing facility temperature controlled by a system of evaporative cooling pads combined with negative pressure ventilation; snout cooler: SC (n = 82), with a cold air outlet directed toward sows, combined with management of curtains; and management of curtains: MC (n = 83). Piglet weight was recorded at cross-fostering, and at 14 and 20 days of age. Temperature (TEMP) and relative humidity (RH) were measured daily at fi ve time points (8:00, 10:00, 12:00, 14:00 and 16:00 h). The variables concerning the sows were analysed with the MIXED procedure of SAS, including the fi xed effect of system and random effects of period and period × system interaction. The weight of piglets, TEMP and RH inside the farrowing facility were analysed as repeated measures using the MIXED procedure. Means were compared with the Tukey-Kramer test. The weight of sows at farrowing, the number of cross-fostered piglets and weight of piglets at cross-fostering were similar among the systems (P > 0.10), with overall means of 241.2 kg, 11.4 piglets and 1.4 kg, respectively.In the AC system, TEMP (23.1ºC) was on average lower (P 0.10) among AC, SC and MC systems regarding sow weight loss during lactation (3.3% vs. 5.0% vs. 4.0%) and weaning-to-estrus interval (4.5 d vs. 5.0 d vs. 4.5 d). The number of weaned piglets was similar among the systems (P > 0.10) with an overall mean of 10.8 weaned piglets. The weight of piglets at weaning tended to be lower (P = 0.083) in the MC than the SC system (5,977 g vs. 6,209 g), whereas piglets of the AC system had an intermediate weight (6,152 g). Discussion: The temperature in SC and MC systems was above the upper critical temperature for sows, mainly between 12:00 and 16:00, which could explain the lower feed intake of sows in the MC system. The higher feed intake of SC sows compared to MC sows is probably related to the microenvironment created by the fresh air over the heads of SC sows improving their thermoregulation and comfort, and preventing a reduction in feed intake. The AC system was the most effi cient in reducing the temperature in the farrowing facility. However, the higher feed intake of AC sows compared to that of MC sows did not result in differences in piglet weight. As the temperature in the AC system was close to the lower critical temperature for the piglets, heating provided to piglets was probably insuffi cient and they required an extra energetic demand for heat production to maintain their body temperature. The higher weight of SC piglets is probably explained by the higher feed intake of sows and by the fact that temperature in the farrowing facility did not decrease as in the AC system