Immunization against gonadotropin-releasing factor (GnRF) in market gilts: Effect on growth and carcass parameters, and impact of immunization timing.

Reproductive cycling in fattening gilts can be associated with undesirable effects, such as estrus-related aggressive behavior, reduced feed intake and, in production systems where gilts are co-housed with entire males, unwanted pregnancy. Immunization against Gonadotrophin Releasing Factor (IM) can temporarily suppress ovarian activity, including related negative consequences on animal welfare and productivity. Feed intake has been shown to be higher after IM, resulting in both increased growth and increased carcass fat. A series of studies was conducted to confirm these effects on production and look at their dynamics over time. Three trials were performed to a similar design, each involving 240 gilts divided into 4 experimental groups at 12 weeks of age. One group remained untreated while the others had the two dose, IM course completed 8, 6 or 4 weeks before harvest, which was on a single day at 24, 25 or 26 weeks of age depending on the study. Feed intake was measured daily and bodyweight weekly, allowing growth parameters to be calculated on a weekly basis and for specific longer periods. Carcass weight, backfat depth and lean meat percentage were recorded at harvest. No effects were observed before the second application of the immunological product (V2) and completion of the IM course. Starting in the second week after V2 all IM groups showed a marked and consistent increase in Average Daily Feed Intake (ADFI), typically peaking at over 120% of the control group 3 to 4 weeks after V2 and then slowly declining, but still remaining elevated at 8 weeks. Weekly Average Daily Gain (ADG) showed a similar pattern but with a faster decline, resulting in the initially favorable impact on feed efficiency becoming less favorable as the V2 to harvest interval (V2H) progressed. Carcass weights were higher in IM gilts and backfat depths were greater, with the effects increasing with increasing V2H. Correspondingly, carcass lean meat percentage tended to decrease, although the higher carcass weights meant that the absolute weight of lean meat remained similar or higher. Carcass yield was generally unaffected by IM, but some between-group differences were statistically significant, and it is possible that different factors predominated at different times after V2, creating a complex relationship with V2H duration. The optimum IM protocol will depend on local conditions and production objectives but, as a generalization and assuming ad libitum feeding, a shorter V2H will favor efficient growth, while a longer duration will maximize carcass changes, such as increased fat coverage. It is suggested that the growth performance changes seen after IM in gilts might be viewed as a process of adjustment to a heavier and fatter target body type.

Prebiotics and butyric acid can replace colistin as a growth promoter for nursery piglets / [Prebióticos e ácido butírico podem substituir a colistina como promotor de crescimento para leitões em fase de creche]

This study aimed to assess different prebiotic concentrations and principles, in addition to calcium butyrate, aiming to replace colistin as a growth promoter. The sample consisted of 120 piglets weaned at 22 days old with mean initial weight of 5.475 ± 0.719kg. The animals were assigned to random blocks in six treatments corresponding to the use of the following dietary additives: T1) colistin (40 ppm); T2) ß-glucan/mannan-oligosaccharides (0.2%); T3) calcium butyrate (0.1%); T4) ß-glucan/mannan-oligosaccharides (0.1%) + fructooligosaccharides (0.01%) + galactooligosaccharides (0.09%); T5) ß-glucan/mannan-oligosaccharides (0.1%) + fructooligosaccharides (0.03%) + galactooligosaccharides (0.07%); and T6) ß-glucan/mannan-oligosaccharides (0.1%) + fructooligosaccharides (0.05%) + galactooligosaccharides (0.05%). The results showed no difference among treatments for the performance parameters in any of the phases evaluated. For diarrhea incidence and intensity, the results indicated that the treatments with alternative additives had similar effects as the group treated with colistin. A significant difference was found for the profile of propionic acid (0.23% colistin and 0.32%, 0.36%, 0.37% additives) and total fatty acids (0.67% colistin and 0.97% additives) values in the caecum. The supplementation with different compositions and concentrations of prebiotics and butyric acid may viably replace colistin in controlling diarrhea and modulating volatile fatty acid production in the caecum.(AU)

O objetivo deste trabalho foi avaliar as diferentes concentrações e princípios de prebióticos e do butirato de sódio, visando substituir a colistina como promotor de crescimento. Foram utilizados 120 leitões, desmamados aos 22 dias de idade, com peso médio inicial de 5,475 ± 0,719kg. Os animais foram distribuídos em blocos ao acaso, em seis tratamentos, que corresponderam ao uso dos seguintes aditivos dietéticos: T1) colistina (40ppm); T2) ß-glucanos/mananoligossacarídeos (0,2%); T3) butirato de cálcio (0,1%); T4) ß-glucanos/mananoligossacarídeos (0,1%) + frutoligossacarídeos (0,01%) + galactoligossacarídeos (0,09%); T5) ß-glucanos/mananoligossacarídeos (0,1%) + frutoligossacarídeos (0,03%) + galactoligossacarídeos (0,07%); e T6) ß-glucanos/mananoligossacarídeos (0,1%) + frutoligossacarídeos (0,05%) + galactoligossacarídeos (0,05%). Os resultados mostraram que não houve diferença entre os tratamentos para nenhum dos parâmetros de desempenho em nenhuma das fases avaliadas. Para a incidência e a intensidade de diarreia, os resultados apontam que os tratamentos com os aditivos alternativos apresentaram efeitos semelhantes aos do grupo tratado com colistina. Foi encontrada diferença significativa para perfil dos ácidos graxos propiônicos (0,23% colistina e 0,32%, 0,36%, 0,37% aditivos) e ácidos totais (0,67% colistina e 0,97% aditivos) no ceco. A suplementação com diferentes composições e concentrações de prebióticos e do ácido butírico pode substituir a colistina de forma viável no controle da diarreia e na modulação da produção volátil de ácidos graxos no ceco.(AU)

Herd-level factors associated with piglet weight at weaning, kilograms of piglets weaned per sow per year and sow feed conversion.

To understand the production factors that affect conclusive parameters of sow herd performance can improve the use of the resources and profitability of farm. The objective of this study was to identify associations and quantify the effects of a set of factors related to piglet weight at weaning (PWW), kilograms of piglets weaned per sow per year (kgPWSY) and sow feed conversion (SFC). Data from 150 farms were collected, for a total study population of 135 168 sows, including gilt replacement, breeding (mating), gestation and farrowing/lactation phases. A questionnaire focusing on reproductive performance, management, facilities, feeding, health and biosafety was administered. Multiple linear regression models were used to assess associations among factors with each of the three dependent variables. Increased duration of lactation was positively associated with PWW, kgPWSY and SFC. The increase in the number of live born pigs per litter was positively associated with kgPWSY and with SFC. Farms with higher PWW had farrowing room humidifiers, did not surgically castrate male piglets and used quaternary ammonia compounds for farrowing room disinfection. Farms with higher kgPWSY used lined ceilings in farrowing rooms and winter feeds with higher CP percentages in gestation; they also had more farrowings per sow per year. Sow feed conversion was worse in farms with partly slatted floors during gestation, in farms feeding lactating sows six times a day or ad libitum and farms with a higher sow-handler ratio. This study indicates that farms can increase PWW and kgPWSY and improve the SFC by changing one or more management, biosafety and feeding practices or facilities as well as by focusing on improving several performance parameters, particularly increasing the duration of lactation and the number of live born pigs per litter.

Caracterização dos fatores de produção e uso de modelos matemáticos para estimar sua influência sobre o consumo diário de ração e a conversão alimentar de suínos nas fases de crescimento e terminação / Characterization of production factors and use of mathematical models to estimate their influence on daily feed intake and feed conversion ratio of grow-finishing pigs

O objetivo deste estudo foi identificar e quantificar os fatores de produção presentes em granjas de crescimento e terminação (CT) de suínos, em um sistema cooperativo do estado do Paraná, Brasil, e determinar a influência desses fatores no consumo diário de ração (CDR) e na conversão alimentar (CA). Foram avaliados, entre os anos de 2010 e 2013, os históricos produtivos de 538 lotes de engorda, alojados em 175 granjas comerciais, totalizando aproximadamente 404.000 animais. Foram considerados 40 fatores de produção, relacionados ao manejo, à sanidade, às instalações e aos equipamentos, à nutrição, à genética e ao ambiente. Em baias com menos de 20 suínos, o CDR diminuiu (P<0,05) e a CA melhorou (P<0,01). Nas baias com comedouros basculantes (lineares), o CDR reduziu (P<0,01) e a CA melhorou (P=0,001). Em baias com lâmina d'água, o CDR aumentou (P<0,01) e a CA piorou (P<0,01). Lotes formados apenas por fêmeas apresentaram menor CDR (P<0,001) e melhor CA (P<0,001), quando comparados aos lotes mistos. As variáveis selecionadas para os modelos finais explicaram cerca de 25% e 46% da variância total para CDR e para a CA, respectivamente. Os modelos constituem um instrumento de auxílio efetivo para tomadas de decisões técnicas dentro do setor suinícola.(AU)

The aim of this study was to identify and quantify the production factors present in growing and finishing (GF) pig farms partners of a cooperative in Paraná State, Brazil, and to determine the influence of these factors on daily feed intake (DFI) and the feed conversion ratio (FCR). From 2010 to 2013, the historical production of 538 batches of fattening pigs in 175 commercial farms were analyzed, in an amount approximately 404,000 animals. A total of 40 production factors regarding the management, sanity, plant and equipment, nutrition, genetics and environment were taken into consideration. Pens with less than 20 pigs resulted in a reduction in DFI (P<0.05) and an improved FCR (P<0.01). In pens that used linear dump feeders, the DFI was less (P<0.01) and the FCR was better (P=0.001). Pens with shallow pools had higher DFI (P<0.01) and worse FCR (P<0.01). Batches of females had lower DFI (P<0.001) and better FCR (P<0.001) compared to mixed-sex batches. The factors used for the final models explained the 25% and 46% of the total variance for the DFI and FCR, respectively. The models consist in effective aid instruments for technical decision making in the swine industry.(AU)