Use of testicular tone and echogenicity in identifying boars with low sperm quality / 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.(AU)

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.(AU)

Ovulation and fertility responses for sows receiving once daily boar exposure after weaning and OvuGel® followed by a single fixed time post cervical artificial insemination.

Boar exposure is used to stimulate follicle development and estrus in sows after weaning and also to improve semen uptake and sperm transport with insemination. However, the need and value of boar exposure is uncertain when ovulation induction is used. These studies were designed to determine the effect of daily boar exposure after weaning when used with ovulation induction and fixed time post-cervical artificial insemination (PCAI). In experiment 1, sows were weaned into stalls and assigned to receive 3 min of daily fenceline boar exposure (BE, n = 7) or no boar exposure (NBE, n = 8). All sows received OvuGel at 96 h after weaning and BE or NBE 30 min prior to a single PCAI 24 h after OvuGel. Ovaries were assessed daily for follicle size from weaning until ovulation. Cervical contractions were measured 30 min following BE or NBE and before PCAI, while uterine contractions were measured for 1 h following PCAI. In experiment 2, weaned sows (n = 244) were assigned by parity to receive once daily BE for 1.5 min each day or NBE. OvuGel, PCAI and ultrasound methods were performed similarly as in experiment 1. Results from experiment 1 indicated BE did not significantly influence follicle size or measures of fertility. However, BE did increase the frequency of cervical contractions (P < 0.05), but with no effect on the uterus. Results from experiment 2 indicated BE had no effect on catheter passage for PCAI but did increase the proportion of sows ovulating within 48 h after OvuGel (77.7 vs 67.5%, P = 0.05), and tended (P = 0.10) to increase the proportion of sows inseminated 24 h before ovulation (70.3 vs. 61.0%). However, BE had no effect on adjusted farrowing rate (84.4 vs. 77.4%) or total pigs born (13.2 vs. 12.5) for BE and NBE, respectively. There were treatment and parity interactions for follicle size at time of OvuGel and at time of PCAI (P < 0.05) with BE minimizing parity effects on follicle size. Parity effects were also evident on farrowing rate and litter size when inseminations occurred >24 h from ovulation but not when inseminations occurred ≤24 h before ovulation. The results indicate that boar exposure for only minutes each day after weaning had beneficial effects for improving follicle development, ovulation induction, and AI timing, most notably in parity 1 sows, but had no beneficial or detrimental effects on the ability to perform PCAI.

Performance of low birth-weight piglets upon protein-energy and/or colostrum supplementation / Desempenho de leitões de baixo peso ao nascimento submetidos à suplementação proteico-energética com ou sem colostro

The study aimed to investigate the effect of oral protein-energy supplement (OPES) and/or extra colostrum within the first few hours of life on the survival and growth performance of low birth-weight piglets during the suckling period. Based upon nutritional strategy, low-birth-weight piglets (804−1309g) were randomly allocated into four groups: C0S0 (control group, n= 300) - no supplementation; C1S0 (n= 299) - supplementation with 50mL of a colostrum pool through an orogastric tube; C0S1 (n= 298) - oral supplementation with 8mL oral OPES; C1S1 (n= 297) - supplementation with both 50mL of colostrum and 8mL of OPES. The piglets' body weight was monitored at birth, 24h after birth, on day 7, day 14 and day 20 post-partum. Both colostrum and protein-energy supplementations did not affect (P>0.05) colostrum intake (253.6g; 259.4g; 259.4g; 263.8g for C0S0, C1S0, C0S1, C1S1, respectively), weight gain during the first 24h (62.6g; 68.3g; 67.1g and 69.8g for C0S0, C1S0, C0S1, C1S1, respectively) and pre-weaning mortality (11.3%, 11.4%, 12.4% and 9.4% for C0S0, C1S0, C0S1, C1S1, respectively). Administration of OPES increased (P= 0.032) the average daily weight gain from birth till weaning (189.1 vs. 182.3g) and tended to increase the weight of the piglets (P= 0.060) at weaning (4893.1 vs. 4746.4g for OPES and no OPES, respectively). In conclusion, nutritional manipulation does not affect colostrum intake and pre-weaning mortality of low birth-weight piglets. However, body weight gain during the suckling period and the weight at weaning were observed to be marginally improved by administration of OPES.(AU)

O objetivo do trabalho foi avaliar o efeito da suplementação oral de suplemento proteico-energético (OPES) e/ou colostro adicional nas primeiras horas de vida sobre a sobrevivência e o desempenho de leitões de baixo peso na fase de maternidade. Foram utilizados leitões com peso entre 804 e 1.309g ao nascimento, alocados aleatoriamente em quatro grupos, de acordo com a estratégia nutricional: C0S0 (grupo controle, n= 300) - sem suplementação; C1S0 (n= 299) - fornecimento de 50mL de colostro, via sonda orogástrica; C0S1 (n=298) - fornecimento de 8mL de OPES; C1S1 (n= 297) - fornecimento de 50mL de colostro + 8mL de OPES. Os leitões foram pesados ao nascimento, 24h, e nos dias sete, 14 e 20 de vida. O fornecimento de colostro ou de OPES não afetou (P>0,05) o consumo de colostro (253,6g; 259,4g; 259,4g; 263,8g para C0S0, C1S0, C0S1, C1S1, respectivamente), o ganho de peso nas primeiras 24h (62,6g; 68,3g; 67,1g e 69,8g para C0S0, C1S0, C0S1, C1S1, respectivamente) e a taxa de mortalidade (11,3%, 11,4%, 12,4% e 9,4% para C0S0, C1S0, C0S1, C1S1, respectivamente). A suplementação com OPES aumentou (P<0,05) o ganho de peso diário do nascimento ao desmame (189,1g vs. 182,3g) e tendeu a aumentar o peso dos leitões (P=0,060) ao desmame (4893,1 vs. 4746,4g para OPES e sem OPES, respectivamente). Conclui-se que a manipulação nutricional de leitões de baixo peso ao nascimento não afeta o consumo de colostro e a mortalidade pré-desmame. No entanto, a administração de OPES aumentou levemente o ganho de peso na maternidade e o peso ao desmame.(AU)

Colostrum yield and litter performance in multiparous sows subjected to farrowing induction.

The consumption of colostrum at a low level can compromise the survival and growth of piglets. Therefore, this study aimed to evaluate the effect of farrowing induction on colostrum yield, IgG concentration and the survival and performance of piglets until the weaning. Sows of parity 3 to 7 were assigned into two groups: Control (n = 48), sows with spontaneous farrowing; and induction (n = 48), sows induced to farrow on day 114 of gestation with a PGF2 analogue. Colostrum and blood samples were collected from the sows, at farrowing and 24 hr later. Blood samples from the piglets were collected at 24 hr after birth. The performance of the piglets was evaluated in a subsample of 28 litters from each group. All piglets were weighed at 7, 14 and 20 days of age. The farrowing length, the number of piglets born alive, stillborn piglets, weight at birth, litter weight at birth and colostrum yield were not significantly affected (p > .05) by farrowing induction. There was no difference between the groups (p > .05) in the percentage of sows with obstetric interventions. Serum IgG concentration, in both sows and piglets, and colostrum IgG concentration were similar between the groups (p > .05). Furthermore, survival rate, piglet weight and litter weight at 7, 14 and 20 days of age were also similar between the groups (p > .05). Therefore, it can be concluded that the farrowing induction performed on day 114 of gestation does not affect the colostrum yield, the IgG concentration in colostrum and serum of piglets, and the litter performance until the weaning.

Fixed-time post-cervical artificial insemination in weaned sows following buserelin use combined with/without eCG.

Fixed-time post-cervical artificial insemination (FTAI) drastically reduces labour requirements and increases the use of boars with higher genetic merit. This study evaluated the efficiency of eCG administration combined with/without the GnRH agonist buserelin for the induction and synchronization of ovulation in weaned sows submitted to FTAI. The sows were allocated into three groups. In the control group, the first artificial insemination was performed at the onset of oestrus and repeated every 24 hr. In the eCG+GnRH group, sows received 600 IU eCG at weaning and buserelin (10 µg) after 86-89 hr of eCG, and in the GnRH group, sows received only buserelin after 86-89 hr of weaning. The hormone-treated sows received a single FTAI after 30-33 hr of buserelin application. All the sows were inseminated with homospermic doses (1.5 × 109  sperm cells/50 ml). The interval between weaning and ovulation was shorter (p < .05) in the eCG+GnRH (133.3 hr) and GnRH (135.9 hr) groups than the control (141.5 hr) group. In the eCG+GnRH group, the sows ovulated earlier (p < .05) than those in the GnRH group (44.5 vs. 48.2 hr after buserelin administration). The reproductive performance of GnRH sows was not compromised when only sows exhibiting oestrus at the time of insemination were considered, but lower farrowing rate and smaller litter size were observed in eCG+GnRH sows. The reproductive performance of eCG+GnRH sows was primarily compromised because the insemination was performed outside the optimal time relative to ovulation; therefore, it is advisable to inseminate them before 116-122 hr after weaning.

Factors influencing colostrum yield by sows / Fatores que influenciam a produção de colostro em porcas

An adequate colostrum intake, in order to ensure the survival and weight gain of piglets, depends on the sow's ability to produce enough colostrum for the whole litter. The aim of this study was to evaluate factors involved in colostrum yield (CY) variability related to the sow, the litter and the farrowing process. The experiment was conducted with 96 Camborough 25(r) sows of parities one to seven, whose farrowing was spontaneous. Colostrum production of each sow was estimated by summing up the colostrum intake of each piglet in the litter, estimated by an equation that takes into account the birth weight and weight gain during the first 24h of life. The multiple regression model explained 28% of variation in CY, with 24% and 4% respectively of variation being explained by the litter birth weight and the width of the first mammary glands. Litter birth weight was positively correlated with the number of total born (r= 0.73) and born alive piglets (r= 0.83). When categorised into two groups of colostrum yield (LOWCY; ≤3.4kg; n= 46 vs HIGHCY; >3.4kg; n= 50), LOWCY sows had fewer total born and born alive piglets and lighter litters (P<0.05). The logistic regression analysis showed that sows from parities 1, 2 and >3 had greater odds (P≤0.05) of belonging to the LOWCY group than parity 3 sows. Sows with two or more obstetrical interventions had higher odds (P<0.05) of belonging to the LOWCY group than sows without interventions during farrowing. The higher colostrum yield observed in sows of parity 3 and sows with less than two obstetrical interventions during farrowing was associated with a greater number of nursed piglets. This study showed that total birth weight of born alive piglets is the most important factor involved in colostrum yield variability, indirectly representing the number of piglets nursed by the sow.(AU)

Um consumo adequado de colostro, para assegurar a sobrevivência e o ganho de peso, dos leitões, depende da capacidade da porca em produzir colostro suficiente para toda a leitegada. O objetivo deste estudo foi determinar fatores relacionados com a porca, com a leitegada ou com o parto que possam influenciar a produção de colostro (PC). O experimento foi conduzido com 96 porcas Camborough 25, de ordem de parto (OP) 1 a 7, cujo parto foi espontâneo. A produção de colostro das porcas foi estimada pela soma do consumo individual de colostro pelos leitões, o qual foi estimado por equação que considera o peso ao nascimento e o ganho de peso nas primeiras 24h de vida. Por meio de modelo de regressão múltipla, 28% da variação na PC foi explicada pelo peso da leitegada (24%) e pela largura do primeiro par de glândulas mamárias (4%). O peso da leitegada foi positivamente correlacionado com o número total de leitões nascidos (r= 0.73) e com o número de leitões nascidos vivos (r= 0.83). Quando separadas em dois grupos de PC (BAIXAPC; ≤3.4kg; n=46 e ALTAPC; >3.4kg; n=50), as porcas do grupo BAIXAPC tiveram menor número total de leitões nascidos, menor número de leitões nascidos vivos e leitegadas mais leves (P<0.05). Por regressão logística, foi observado que porcas da OP 1, 2 e >3 tiveram maior chance (P≤0.05) de pertencer ao grupo BAIXAPC do que porcas de OP 3. Porcas com duas ou mais intervenções obstétricas tiveram maior chance (P<0.05) de pertencer ao grupo BAIXAPC do que as porcas sem intervenção durante o parto. A maior PC observada nas porcas de OP 3 e nas porcas com menos intervenções obstétricas foi associada com um maior número de leitões amamentados. Foi mostrado, neste estudo, que o peso total da leitegada viva, o qual indiretamente representa o número de leitões amamentados pela porca, é o fator mais importante envolvido na produção de colostro.(AU)

Single fixed-time artificial insemination in gilts and weaned sows using pLH at estrus onset administered through vulvar submucosal route.

This study evaluated the use of a single fixed-time artificial insemination (FTAI) in gilts and weaned sows using 2.5 mg of porcine luteinizing hormone (pLH) administered through vulvar submucosal route, at the onset of estrus. In experiment 1 (Exp.1), 318 pubertal gilts were assigned to two groups: control-G-no hormonal application and artificial inseminations (AIs) at 12, 36, and 60 hours after the onset of estrus if they were still in standing estrus; and FTAI-G-use of pLH at the onset of estrus and a single FTAI 12 hours later. In experiment 2 (Exp. 2), 309 weaned sows were assigned to three groups: Control-S-no hormone application and AIs at 0, 24, and 48 hours after the onset of estrus if they were still in standing estrus; FTAI-NH-no hormone application and a single FTAI at 24 hours after the onset of estrus, and FTAI-pLH-use of pLH at the onset of estrus and a single FTAI 24 hours later. Transabdominal real time B-mode ultrasonography was performed to determine whether the insemination had been performed within 24 hours before ovulation, considered as the optimal interval. In Exp. 1, ultrasound evaluation (12-hour intervals) was carried out to determine the interval between the onset of estrus and ovulation. In both experiments, 2 × 10(9) sperm cells in 80 mL were used to perform cervical and postcervical deposition of semen in gilts and sows, respectively. Compared with control-G, FTAI-G gilts had shorter (P < 0.05) duration of estrus (57.7 vs. 61.2 hours) and interval between the onset of estrus and ovulation (36.3 vs. 42.3 hours). The adjusted farrowing rate (AFR) was lower (P < 0.05) in FTAI-G (86.0%) compared with control-G (93.5%), but total piglets born (TPB) did not differ between these groups (12.3 vs. 12.5 piglets). Within the FTAI-G group, the AFR was lower (P < 0.05) in the presence (50.0%) than in the absence (94.9%) of semen backflow during AI. Also in the FTAI-G group, the insemination outside the optimal interval reduced (P < 0.05) the TPB (10.5 vs. 12.9 piglets) in comparison with gilts inseminated within the optimal interval. In Exp. 2, there were no differences in the AFR (Control-S: 94.1%; FTAI-NH: 86.1%; FTAI-pLH: 88.0%) and TPB (Control-S: 12.8; FTAI-NH: 12.7, and FTAI-pLH: 12.0 piglets) among treatments. The presence of semen backflow reduced (P < 0.05) the TPB in FTAI-pLH and FTAI-NH sows. In the FTAI-pLH, a single insemination performed too late relative to ovulation reduced the AFR (P < 0.05) compared with sows inseminated within the optimal interval. In conclusion, 2.5-mg pLH applied at the vulvar submucosa at the onset of estrus advances the ovulation in gilts, but a single FTAI performed 12 hours later reduces the farrowing rate. A single FTAI performed at 24 hours after the onset of estrus in weaned sows does not affect their reproductive performance, regardless of pLH application.

New Artificial Insemination Technologies for Swine.

Better efficiency in swine artificial insemination (AI) is accomplished by reducing the necessary number of sperm cells and achieving high reproductive performance. Some strategies have been developed for use under field conditions, such as the site of sperm deposition (post-cervical AI), a single AI with control of oestrus and ovulation (fixed-time AI), and the better use of high genetic merit boars, to spread their genes as much as possible. To apply these technologies, it is important to understand some anatomical limits, physiological aspects and farm requirements. In this review, we point out some strategies to achieve higher efficiency on the use of sperm for AI technology application in swine species.

Effect of body development from first insemination to first weaning on performance and culling until the third farrowing of Landrace x Large White swine females / Efeito do desenvolvimento corporal desde a primeira inseminação até o primeiro desmame no desempenho e descarte até o terceiro parto de fêmeas suínas Landrace x Large White

The aim of this study was to verify the association of sow body weight development until the 1st weaning with reproductive performance, piglet production and culling rate until the 3rd farrowing in 196 primiparous sows using logistic regression models. Each 10kg increase in weight gain in the 1stpregnancy (OR= 0.63), weight at 1st farrowing (OR= 0.70), weight at the 1st weaning (OR= 0.73) or weight gain from the 1startificial insemination (AI) to the 1st weaning (OR= 0.67) decreased the percentage of primiparous sows with long weaning-to-oestrus interval - WOI (>5 days). An increasing lactation length and an increase in the number of weaned piglets were responsible for respectively decreasing (OR= 0.77-0.80, per day of lactation) and increasing (OR= 1.52-1.59, per piglet weaned) the percentage of sows with long WOI. Sows with <159.5kg at weaning had higher odds of non-farrowing (NFR) compared to sows with >170kg (OR= 4.73). Sows with <17.5kg of gain from the 1st AI to the 1st weaning had higher odds (OR= 4.88) of NFR than sows gaining >30kg. Each additional lactation day decreased the NFR (OR= 0.74). Females weighing <139kg at the 1st AI had higher percentages of small numbers of total born in the second parity (STB2, OR= 2.00) and over three parities (OR= 3.28) compared to those weighing ≥139kg. Sows with weight gain <25kg at the 1st pregnancy had higher odds of STB2 (OR= 3.01) compared to sows gaining >35kg. Each 10kg of increase in weight at the 1st weaning or in weight gain from the 1st AI to the 1st weaning decreased the total culling rate (OR= 0.71 and 0.73, respectively) and culling for reproductive reasons (OR= 0.57 and 0.61, respectively). The culling rate until the 3rdfarrowing was also increased in sows with a smaller first litter size. The results show that not only reaching a minimum weight at the 1st AI but also having an adequate body weight gain until the 1st weaning is important for the reproductive performance, productivity and retention of Landrace x Large White Danbred sows in the herd.(AU)

O objetivo do estudo foi verificar, com modelos de regressão logística, a associação entre características de desenvolvimento corporal até o 1º desmame com o desempenho reprodutivo, produção de leitões e taxa de remoção até o 3º parto de 196 fêmeas suínas primíparas. Houve redução nas chances de as fêmeas terem intervalo desmame-estro (IDE) longo (>5 dias) a cada 10kg de aumento no ganho de peso na 1ª gestação - GPG1 (razão de chance - RC = 0,63), peso no 1º parto - PP1 (RC= 0,70), peso no 1º desmame - PD1 (RC= 0,73) ou ganho de peso da 1ª inseminação artificial (IA) ao 1º desmame - GPIAD1 (RC= 0,67). O percentual de porcas com IDE longo reduziu com o aumento da duração da lactação (RC= 0,77-0,80, por dia de lactação) e aumentou com o aumento no número de leitões desmamados (RC= 1,52-1,59, por leitão desmamado). Porcas com <159,5kg ao desmame tiveram maior chance de não parir (NP) em comparação a porcas com >170 kg (RC= 4,73). Porcas com <17,5kg de GPIAD1 tiveram maior chance (RC= 4,88) de NP do que porcas ganhando >30kg. O aumento da duração da lactação reduziu a chance de NP (RC= 0,74, para cada dia). Fêmeas com <139kg na 1ª IA tiveram maior chance de terem leitegada pequena no segundo parto - LPSP (RC= 2,00) ou ao longo de 3 partos (RC= 3,28), em comparação às fêmeas com ≥139kg. Fêmeas com GPG1 <25kg tiveram maior chance de LPSP (RC= 3,01) do que fêmeas com >35kg. Houve diminuição na taxa geral de descarte (RC= 0,71 e 0,73, respectivamente) e descarte por causas reprodutivas (RC= 0,57 e 0,61, respectivamente) para cada 10kg de aumento no PD1 e GPIAD1. A taxa de descarte até o 3º parto também aumentou nas porcas com menor leitegada no primeiro parto. Os resultados mostram que, além de atingir um peso mínimo na 1ª IA, o ganho de peso entre a 1ª IA e o primeiro desmame é importante para o desempenho reprodutivo, produtividade e retenção de fêmeas Danbred Landrace x Large White no rebanho.(AU)

Use of porcine luteinizing hormone at oestrous onset in a protocol for fixed-time artificial insemination in gilts.

The aim of this study was to evaluate the effect of porcine luteinizing hormone (pLH) given at oestrous onset in gilts, by different routes and doses, on the interval between onset of oestrus and ovulation (IOEO) and reproductive performance using a single fixed-time artificial insemination (FTAI). A total of 153 gilts were submitted to oestrous detection at 8-h intervals and assigned to three groups: control - without hormone application and inseminated at 0, 24 and 48 h after oestrous onset; VS2.5FTAI - 2.5 mg pLH by the vulvar submucosal route at oestrous onset and a single FTAI 16 h later; IM5FTAI - 5 mg pLH by the intramuscular route at oestrous onset and a single FTAI 16 h later. More VS2.5FTAI gilts (47.1%; p < 0.05) ovulated within 24 h after oestrous onset than control gilts (25.5%) whereas IM5FTAI gilts had an intermediate percentage (31.4%; p > 0.05). The IOEO tended to be shorter (p = 0.06) in VS2.5FTAI (30.2 ± 1.4 h) than in control (34.7 ± 1.4 h) gilts, but there was no difference (p > 0.05) between control and IM5FTAI (32.8 ± 1.4 h) gilts. Farrowing rate was not different (p > 0.05) among treatments. Total born piglets (TB) was lower (p < 0.05) in VS2.5FTAI (12.3 ± 0.4) than in control gilts (14.1 ± 0.4), whereas intermediate TB was observed in IM5FTAI gilts (13.3 ± 0.4). Due to the advancement of ovulation, reduction of the hormonal dose and the ease of application, the vulvar submucosal route would be the best option for FTAI protocols, but their negative impact on litter size remains to be elucidated. Taking into account the good fertility results obtained in IM5FTAI gilts whose ovulation was not advanced, the possibility of a single FTAI without any hormonal treatment should be further investigated, to establish reliable FTAI protocols for gilts.

Behaviour and growth performance of low-birth-weight piglets cross-fostered in multiparous sows with piglets of higher birth weights / Comportamento e desempenho de crescimento de leitões com baixo peso ao nascer uniformizados com leitões de maior peso em fêmeas suínas multíparas

The aim of the study was to evaluate the behaviour, pre-weaning survival rate and growth performance of low birth weight (BW) piglets cross-fostered with piglets of higher weights. Piglets were transferred to 60 foster sows, and divided in three groups (G; n=20): G1- 12 low BW piglets (0.80 - 1.25kg); G2- six low BW piglets and six intermediate BW piglets (1.40 - 1.60kg), and G3- six low BW piglets and six high BW piglets (>1.70kg). For the analysis, groups G2 and G3 were subdivided in LG2 (six G2 light piglets); IG2 (six G2 intermediate piglets), LG3 (six G3 light piglets), and HG3 (six G3 heavy piglets). Behavioural observations were carried out on days 1, 2, 4 and 6 (visual direct observation) and on days 3 and 5 (video recording) after birth. The percentage of missed nursings was higher in LG3 piglets than in LG1, IG2 and HG3 piglets, on days 1 and 2. On day 4, light piglets (LG1, LG2 and LG3) missed more nursings than IG2 and HG3 piglets. On day 3, video recording showed a higher percentage of missed nursings in LG1, LG2, and LG3 piglets as compared to HG3 piglets. On day 1, the number of fights during nursing was higher in IG2 than in LG1 and LG3 piglets. Also on day 1, number of fights and percentage of piglets engaged in fights, during 15min after nursing, were higher in LG1, LG3 and HG3 than in LG2 piglets. More playful behaviours were observed on day 2 in IG2 and HG3 piglets compared to LG1, LG2 and LG3 piglets. Light piglets (LG1, LG2, and LG3) presented similar body weight on days 4, 8, 12 and 16 after birth, regardless of being mixed with piglets of higher weights or not; however, the survival rate until day 16 was most compromised in LG3 piglets compared to the other groups. Despite the lack of influence of littermates' weight on the growth of low BW piglets, their survival rate indicates that they should not be mixed with high BW piglets...

O objetivo do estudo foi avaliar o comportamento, a taxa de sobrevivência pré-desmame e o desempenho de crescimento de leitões leves ao nascer uniformizados com leitões de maior peso ao nascer (PN). Os leitões foram transferidos para 60 fêmeas e divididos em três grupos (G; n=20): G1 - 12 leitões de baixo PN (0,80-1,25kg); G2 - seis leitões de baixo PN e seis com PN intermediário (1,40-1,60kg); e G3 - seis leitões de baixo PN e seis leitões pesados (>1,70kg). Para a análise, os grupos G2 e G3 foram subdivididos em LG2 (seis G2 leitões leves); IG2 (seis G2 leitões de peso intermediário); LG3 (seis G3 leitões leves) e HG3 (seis G3 leitões pesados). Observações de comportamento foram realizadas nos dias 1, 2, 4 e 6 (observações visuais diretas) e nos dias 3 e 5 (gravações) após o nascimento. A porcentagem de mamadas perdidas foi maior no grupo LG3 quando comparado aos grupos LG1, IG2 e HG3, nos dias 1 e 2. No dia 4, leitões leves (LG1, LG2 e LG3) perderam maior número de mamadas do que os grupos IG2 e HG3. No dia 3, a gravação mostrou maior porcentagem de perda de mamadas nos grupos LG1, LG2 e LG3 do que no grupo HG3. No dia 1, o número de brigas durante a mamada foi maior nos grupos IG2 do que nos grupos LG1 e LG3. Também no dia 1, o número de brigas e porcentagem de leitões envolvidos em brigas, durante 15 minutos após a mamada, foi maior nos grupos LG1, LG3 e HG3 do que no grupo LG2. Brincadeiras foram mais observadas no dia 2 nos grupos IG2 e HG3 quando comparado aos grupos LG1, LG2 e LG3. Leitões leves (LG1, LG2 e LG3) apresentaram peso semelhante nos dias 4, 8, 12 e 16 após o nascimento, independentemente de serem misturados ou não com leitões pesados. No entanto, a taxa de sobrevivência até o dia 16 foi mais comprometida nos leitões do grupo LG3 do que nos outros grupos. Apesar da falta de influência do peso das leitegadas no crescimento de leitões de baixo PN, a taxa de sobrevivência indicou que estes não devem ser misturados com leitões de maior PN...

Effect of birth weight and colostrum intake on mortality and performance of piglets after cross-fostering in sows of different parities.

The objective of this study was to evaluate the effect of colostrum intake on mortality and growth performance of piglets until 42 days of age, taking into account the birth weight, and parity order of sows. Colostrum intake from birth to 24h after birth was estimated in 300 piglets each from primiparous and multiparous sows. The piglets were cross-fostered in 25 primiparous and 25 multiparous sows at 25.9±0.09 h after farrowing. The concentration of serum immunoglobulin G (IgG) was determined in the sows after the end of farrowing and in the piglets before cross-fostering (24h after farrowing), at 10 and 20 days of age. For high birth weight piglets (HBW - >1.3-1.7 kg) the probability of death was low regardless of their colostrum intake. Intermediate birth weight (IBW - >1.2-1.3 kg) and low birth weight (LBW - 1.1-1.2 kg) piglets had the same probability of death compared to HBW piglets, when colostrum intake reached 200 and 250 g, respectively. The probability of low performance (<9.5 kg) was lower in HBW than in LBW and IBW piglets, regardless of colostrum intake. HBW piglets had higher weight at 14, 20, 28 and 42 days of age (P<0.05) than LBW piglets, and higher weight than IBW piglets at 28 and 42 days. Colostrum intake >250 g increased (P<0.05) the weight of piglets at 28 and 42 days of age, regardless of their birth weight. Piglets from primiparous biological dams consumed less colostrum (P<0.003) than piglets from multiparous dams, but their serum IgG concentrations at 24h after birth and their performance were similar (P>0.05). Piglets suckled by primiparous foster sows showed lower weight (P<0.05) at 20, 28 and 42 days than piglets suckled by multiparous sows. Piglets that died before 42 days of age had lower (P<0.05) birth weight, colostrum intake and serum IgG at 24 h after birth compared to surviving piglets, and lower values were also observed in piglets with low performance compared to high (>9.5 kg) performance piglets. There were no differences in serum IgG concentrations at 10 and 20 days of age (P>0.05) between high and low performance piglets. In conclusion, both colostrum intake and birth weight are important for survival and growth of suckling piglets. LBW and IBW piglets are more dependent on colostrum intake than HBW piglets to assure higher survival and better development up to 42 days of age. Piglets suckled by multiparous sows have better development than those suckled by primiparous sows.

Fixed-time post-cervical artificial insemination in sows receiving porcine luteinising hormone at oestrus onset.

Fixed-time post-cervical artificial insemination (FTPCAI) allows a wider use of high indexing boars and a considerable reduction in labour requirements in swine production. The aim of this study was to evaluate fixed-time artificial insemination (FTAI) efficiency using different artificial insemination protocols and porcine luteinising hormone (pLH) to induce ovulation. A total of 597 weaned sows in which oestrus detection was performed once daily (08:00 am) was allocated to three groups: FTPCAI1 (n=199) - sows received a 5-mg (4 ml) intramuscular injection of pLH at oestrus onset, and were inseminated 24h later; FTPCAI2 (n=199) - sows received 5mg of pLH and were inseminated at oestrus onset (0 h) and 24h after; and MultPCAI (n=199) - sows did not receive pLH, and the first AI was performed at oestrus onset (0 h) and repeated every 24h during oestrus. Homospermic doses (1.5 × 10(9) total sperm cells/50 ml) were used in post-cervical artificial insemination (PCAI) in all the treatments. Hormonal treatment did not affect (P>0.05) the interval between oestrus onset and ovulation (overall 32.4h) and there were no differences (P>0.05) in farrowing rate (overall 91.6%) or litter size (overall 12.6 piglets born) among treatments. In sows treated with pLH at oestrus onset, a single PCAI with 1.5 billion sperm cells did not compromise reproductive performance compared with a double PCAI at 24h intervals.

The post-cervical insemination does not impair the reproductive performance of primiparous sows.

The study evaluated the reproductive performance of primiparous sows submitted to post-cervical insemination (PCAI) compared with cervical artificial insemination (CAI). Difficulty with catheter introduction, the occurrence of bleeding or semen backflow during insemination, and volume and sperm cell backflow up to 60 min after insemination were also evaluated. Sows were homogenously distributed, according to body weight loss in lactation, lactation length, weaned piglets, weaning-to-oestrus interval and total born in previous farrowing, in two treatments: PCAI (n = 165) with 1.5 × 10(9) sperm cells in 45 ml (2.4 ± 0.04 doses per sow) and CAI (n = 165) with 3 × 10(9) sperm cells in 90 ml (2.5 ± 0.04 doses per sow). During PCAI, sows were inseminated in the absence of boars. Transabdominal real-time ultrasonography was performed at oestrus onset, immediately before the first insemination and at 24 h after last insemination. There was no difference (P > 0.05) between treatments in farrowing rate (91.5% × 89.1%) and litter size (12.5 × 11.9 piglets born, respectively for PCAI and CAI sows). Successful passage of the intrauterine catheter in all the inseminations was possible in 86.8% (165/190) of sows initially allocated to PCAI treatment. Difficulty of introducing the catheter in at least one insemination did not affect the reproductive performance of PCAI sows (P > 0.05). Bleeding during insemination did not affect (P > 0.05) the farrowing rate in both treatments, but litter size was reduced in CAI and PCAI sows (P ≤ 0.06). Percentage of spermatozoa present in backflow within 1 h after insemination was greater in CAI than PCAI sows (P < 0.01). More than 85% of primiparous sows can be successfully post-cervical inseminated with doses containing 1.5 × 10(9) sperm cells in the absence of the boar during insemination without impairing the reproductive performance.

Efeito da ordem de parto e da perda de peso durante a lactação no desempenho reprodutivo subsequente de matrizes suínas / The effect of parity order and lactation weight loss on subsequent reproductive performance of sows

Investigou-se o efeito da ordem de parto (OP) e da perda de peso durante a lactação no desempenho reprodutivo de 666 matrizes suínas. Foram formadas três classes de OP (OP1, OP2 e OP3-5) e duas classes de percentual de perda de peso (≤1% e >1%) durante a lactação. Foram avaliados: taxa de parto, intervalo desmame-estro (IDE) e tamanho da leitegada subsequente. Houve interação de OP versus perda de peso na taxa de parto das fêmeas (P<0,05). As fêmeas OP1 e OP2 tiveram maior chance (P<0,05) de não parir na classe >1% de perda de peso. A maior perda de peso não foi um fator de risco para não parir na condição OP3-5 (P>0,05). Não houve interação de OP versus perda de peso (P>0,05) para IDE e total de leitões nascidos. Fêmeas OP1 apresentaram IDE mais longo e menor tamanho da leitegada no parto subsequente (P<0,05) do que fêmeas OP2 e OP3-5. As perdas corporais na lactação não influenciaram o IDE (P>0,05), mas reduziram o tamanho da leitegada subsequente (P<0,05). Conclui-se que maior perda de peso na lactação resulta em aumento de falhas reprodutivas nas fêmeas mais jovens e reduz o tamanho da leitegada subsequente em todas as OP.

The effect of parity (PO) and weight loss during lactation on the subsequent reproductive performance of 666 sows was investigated. Sows were allocated into three PO classes (PO1, PO2 and PO3-5) and into two classes of weight loss percentage (≤1% and >1%) during lactation. Farrowing rate, weaning to estrus interval (WEI) and total born at next farrow were evaluated. There was an interaction effect between PO and weight loss on the farrowing rate (P<0.05). PO1 and PO2 females had more chance (P<0.05) of failure to farrow when weight loss was higher than 1%. However, the higher weight loss was not a risk factor to low farrowing rate in PO3-5 females (P>0.05). There was no interaction between PO and weight loss (P>0.05) on WEI and subsequent total born. PO1 females showed longer WEI and lower litter size on subsequent farrowing compared to PO2 and PO3-5 females. Weight loss did not affect WEI (P>0.05), but it decreased subsequent litter size (P<0.05). High weight loss during lactation results an increase in reproductive failures in young females and decreases subsequent litter size in all parity orders.

Multivariate analyses for determining the association of field porcine fertility with sperm motion traits analysed by computer-assisted semen analysis and with sperm morphology.

This study investigates the association of semen traits with boar fertility. The fertility outcome (farrowing rate - FR and total piglets born - TB) of 14 boars was obtained from a field trial conducted during 10 week of breeding period on a commercial farm using multiparous sows (n = 948) through single-sire mating with 2 × 10(9) motile sperm cells per artificial insemination (AI) dose. Sperm motion parameters, evaluated with computer-assisted semen analysis system in raw and stored semen at 17°C for 240 h, in addition to morphological sperm defects, measured on the collection day, were included in the analysis to determine which semen traits were important to discriminate the fertility potential of ejaculates from these boars. The data underwent multivariate cluster, canonical and discriminant analyses. Four clusters of boars were formed based on fertility outcome. One boar, with the lowest FR and TB values (89.7% and 11.98), and two boars, with the highest FR and TB values (97.8% and 14.16), were placed in different clusters. The other boars were separated in two distinct clusters (four and seven boars), including boars with intermediate TB (12.64 and 13.22) but divergent values for FR (95.9% vs 91.8%). Semen traits with higher discriminatory power included total motility, progressive motility, amplitude of lateral head displacement and cytoplasmatic droplets. Through multivariate discriminant analysis, more than 80% of the 140 ejaculates were correctly classified into their own group, showing that this analysis may be an efficient statistical tool to improve the discrimination of potential fertility of boars. Nevertheless, the validation of the relationship between fertility and semen traits using this statistical approach needs to be performed on a larger number of farms and with a greater number of boars.

Altrenogest treatment associated with a farrowing induction protocol to avoid early parturition in sows.

This study investigated the effect of altrenogest treatment on the farrowing development of sows, and birth weight (BW) and piglet survival until the third day of life. Three control groups were used: (i) sows that farrowed spontaneously before 114 day of gestation (CONT <114); (ii) sows that spontaneously farrowed at ≥114 day of gestation (CONT ≥114); (iii) sows that farrowed at ≥114 day with cloprostenol treatment (CONTCLOPR). Other sows were treated with altrenogest (Regumate(®) ) for 3 days (days 111, 112 and 113 of gestation): one group gave birth spontaneously (ALT) and the other group received altrenogest until day 113 and cloprostenol on day 114 (ALTCLOPR). There were no differences (p > 0.05) in farrowing duration, BW, coefficient of variation (CV) of BW, stillborn piglets, mummified foetuses, percentage of light piglets and survival until Day 3 between sows with and without cloprostenol treatment, in both control (CONT ≥114 vs CONTCLOPR) and altrenogest-treated sows (ALT vs ALTCLOPR). Further comparisons were performed taking into account three groups: sows with early delivery (CONT <114 - farrowing before 114 days of gestation; n = 56), sows with longer gestation (CONT ≥114 - with and without cloprostenol treatment sows; n = 103) and ALT sows (with and without cloprostenol treatment; n = 105). Gestation length of CONT ≥114 and ALT sows was similar (p > 0.05), but higher than in CONT <114 sows. There were no differences (p > 0.05) between groups in farrowing duration, CV of BW, and percentages of stillborn piglets and mummified foetuses. Sows of CONT <114 group had a larger litter size and a lower BW than sows of the other two groups (p < 0.05). Sows of CONT <114 group had a higher percentage of lighter piglets and a lower piglet survival rate (p < 0.05) than ALT sows. In conclusion, altrenogest treatment proved to be an efficient method to avoid early parturition in 3-5 parity sows resulting in heavier piglets at birth.

Newborn piglet traits associated with survival and growth performance until weaning.

Pre-weaning piglet mortality represents significant economic losses, and approximately half of this mortality occurs within the first 3 days after birth. Factors involved in postnatal mortality can also be associated with a poor growth performance until weaning. The aim of this study was to evaluate the effect of some variables measured right after birth on piglet survival during the first week of life and growth performance until weaning. Piglets included in the analysis (n=612) were born from 3 to 5 parity sows. Piglets were monitored for blood oxygen saturation (SatO2), heart rate (HR), blood glucose concentration, rectal temperature at birth (RT0 h) and at 24h after birth (RT24 h). Genetic line, birth following or not an obstetric intervention, birth order, sex, skin color, integrity of the umbilical cord, and time elapsed from birth until first attempts to stand were also recorded. Piglets were weighed at birth (BW), and at 7, 14 and 21 days after birth in order to evaluate their postnatal development. Cumulative mortality rates were 3.3%, 5.4% and 8.7% at 3, 7 and 21 days after birth, respectively. Body temperature at birth (RT0 h) did not affect (P>0.05) the survival nor the piglet growth performance. Piglets with cyanotic skin and those that took more than 5 min to stand showed higher chance of mortality (P<0.05) compared to normal skin piglets and to piglets which stood before 1 min, respectively. Piglets with broken umbilical cord had higher odds (P<0.05) of mortality up to 3 days after birth, respectively. Higher odds (P<0.05) of mortality up to 3 or 7 days were associated with later birth order (>9), low BW (<1275g), low (24-30 mg/dl) and high (45-162 mg/dl) blood glucose concentrations, or low RT24 h (<38.1°C). Piglets with BW<1545 g, low RT24 h (<38.6°C) and female piglets had higher odds of a low weight at weaning (P<0.05). Among the factors studied, cyanotic skin, delay for standing, broken umbilical cord, high birth order, low BW, low RT24 h, and both low and high blood glucose concentrations are indicators of a lower ability of piglets to survive during the first week after birth. The growth performance until weaning is compromised in piglets with a lower BW, a lower RT24 h and if they are female pigs.

Absorção de IgG via colostro em leitões biológicos e adotados após a uniformização da leitegada / Absorption of IgG via colostrum in biological piglets and adopted piglets after crossfostering

Nove fêmeas de quinto parto (OP5) foram imunizadas com 4mg e 2mg de albumina sérica bovina (BSA) aos 70 e 100 dias de gestação, respectivamente. A uniformização da leitegada foi realizada 4,9±1,9h após o nascimento, antes de os leitões efetuarem a primeira mamada. As leitegadas foram compostas por cinco leitões biológicos (LB) e cinco leitões adotados (LA), com pesos semelhantes ao nascimento. Foram coletadas amostras de sangue dos leitões ao nascimento e 24h após, das fêmeas ao pós-parto e de colostro de cada grupo de tetos ao parto e 24h após. As amostras de soro e colostro foram quantificadas para IgG pelo ELISA indireto. A densidade ótica de IgG anti-BSA (DOIgG-BSA) dos leitões (24h de vida) foi correlacionada com a das fêmeas. A DOIgG-BSA entre LB e LA foi semelhante, assim como entre os grupos de tetos, ao parto e 24h após. Entretanto, ocorreu redução na DOIgG-BSA do parto até 24h após. LB e LA absorveram a mesma quantidade de IgG via colostro, quando a uniformização foi realizada até 5h pós-parto, independentemente do teto em que os leitões mamaram, uma vez que esses possuem a mesma concentração de IgG.

Nine sows of fifth parity (PO5) were immunized with 4mg and 2mg of bovine serum albumin (BSA) at 70 and 100d of gestation, respectively. Cross fostering was performed 4.9±1.9h after birth, before piglets had their first suckling. Litters were composed of five biological piglets (BP) and five adopted piglets (AP), with similar weight at birth. Blood samples were collected from piglets (at birth and at 24h of life) and from females (after farrowing) and colostrum from each group of teats (at farrowing time and after 24h). Samples of serum and colostrum were quantified to IgG by indirect ELISA. Optical density of IgG anti-BSA (ODIgG-BSA) from piglets (24h of life) was correlated with dams. ODIgG-BSA was similar among BP and AP, as well as among pairs of teats (at farrowing time and after 24h). However, there was a decrease in ODIgG-BSA from farrowing up to 24h after birth. BP and AP absorbed the same amount of IgG via colostrum, when cross fostering was evaluated 5h after farrowing, regardless of the teat suckled, since these have the same concentration of IgG.

Effects of breeding at the second oestrus or after post-weaning hormonal treatment with altrenogest on subsequent reproductive performance of primiparous sows.

This study investigated the effects of breeding at the second oestrus after weaning or after feeding an orally active progestagen (altrenogest) on the subsequent reproductive performance of primiparous sows. After 3 weeks of lactation, 663 weaned sows of two genotypes were allocated into three groups: G1--breeding at the first oestrus after weaning; G2--breeding at the second oestrus after weaning and G3--treatment with altrenogest for 5 days after weaning and breeding at the first oestrus after the end of the treatment. Body weight at breeding was lower in G1 and G3 than in G2 sows (p < 0.05). The interval to show oestrus was similar for G1 and G2 groups (p > 0.05) but higher (p < 0.05) than that observed in G3 group. Within genotype A, percentages of females in oestrus within 10 days were not different (p > 0.05) among groups, whereas in genotype B, more G1 and G2 sows (p < 0.05) showed oestrus than G3 sows. In both genotypes, lower farrowing rates were observed in G3 than in G1 and G2 sows (p < 0.05) and a greater litter size (p < 0.05) was observed in G2 sows. In genotype A, the number of total born piglets was similar for G1 and G3 groups (p > 0.05), whereas in genotype B, G1 sows had a greater litter size than G3 sows (p < 0.05). Body weight at weaning and at breeding was similar (p > 0.05) between farrowed and non-farrowed sows in all groups. Reproductive performance is not improved in primiparous sows treated with altrenogest during 5 days after weaning. The reproductive performance of genotype B sows is compromised in Control and Altrenogest-treated sows but not in those bred at the second oestrus after mating. Breeding at the second oestrus after weaning allows primiparous sows to gain weight between weaning and service, and increases their farrowing rate and subsequent litter size.