Effects of different amounts and type of diet during weaning-to-estrus interval on reproductive performance of primiparous and multiparous sows.

During weaning-to-estrus interval (WEI), the sows are usually fed with high feed level to improve the reproductive performance. However, the WEI has been reduced over the years which may reduce the impact of feed level on performance in the modern genetic lines. The aim of this study was to evaluate the effect of two feeding levels (moderate feeding level (MFL): 2.7 kg/day and high feeding level (HFL): 4.3 kg/day) and two diet types (gestation: 13.67 MJ/kg of metabolizable energy (ME) and 0.62% of standard ileal digestible lysine (SID Lys) and lactation: 14.34 MJ ME/kg and 1.20% of SID Lys) offered during the WEI on reproductive performance. In total, 19.0% of sows were excluded from the analysis due to feed intake below 75% (9.6% and 28.5% in MFL and HFL groups, respectively), remaining 254 primiparous and 806 multiparous sows. Follicular size and change in BW were measured in subsamples of 180 and 227 females, respectively. Data were analyzed considering the sow as the experimental unit. Feeding level, diet type, parity and their interactions were included as fixed effects, whereas the day of weaning was considered as a random effect. The feed intake of MFL and HFL groups averaged 2.5 ± 0.02 and 3.8 ± 0.02 kg/day, respectively. There was an interaction between feeding level and parity for daily feed intake. Within HFL, multiparous sows consumed 181 g/day more than primiparous sows (P < 0.01), but no difference was observed within MFL (P > 0.05). Both primiparous and multiparous sows lost proportionally less weight when fed HFL than MFL gestation diet during WEI. The percentage of weight loss was lower in HFL than in the MFL group in multiparous sows fed the lactation diet. The WEI was not affected by feeding level, diet type or its interaction (P > 0.05), but it was longer in primiparous than in multiparous sows (P = 0.001). There was no effect of feeding level, diet type, parity or their interactions on anestrus and farrowing rates. Multiparous sows showed greater follicular size, and greater numbers of total born and born alive piglets in the subsequent cycle than primiparous sows (P < 0.05). In conclusion, feeding weaned primiparous and multiparous sows with 4.3 kg/day of a gestation (58.78 MJ ME and 26.66 g SID Lys) or a lactation diet (61.66 MJ ME and 51.60 g SID Lys) does not improve follicular size and reproductive performance in the subsequent cycle.

Impact of housing nursery pigs according to body weight on the onset of feed intake, aggressive behavior, and growth performance.

Housing nursery pigs according to body weight is an observed common practice in production systems and, supposedly, improves growth performance and reduces body weight (BW) variation. This 42-day study evaluated the effects of housing nursery pigs according to BW on performance, onset of feed intake, and aggressive behavior. A total of 504 pigs were ranked by BW at weaning and categorized into three groups of 168 pigs each: light, medium, and heavy. Pigs were randomly distributed to unsorted pens (Unsorted) containing 6 pigs of each weight group and sorted pens with 18 pigs from just one group per pen (Sorted). From weaning to day 3, pigs were fed a diet containing 1% iron oxide dye and rectal swabs presenting red coloration were evaluated to assess feed intake onset. Eight pens were video recorded to evaluate aggressive behavior. Sorted-Heavy pigs delayed the onset of feed intake (P ≤ 0.011) and presented more aggressive behaviors than Sorted-Light and Sorted-Medium pigs (P ≤ 0.036). In Unsorted, onset of feed intake showed no differences between weight categories. Also, no differences were observed for aggressive behavior between Sorted and Unsorted. Final BW showed no differences between Sorted and Unsorted pigs. The within-pen weight coefficient variation (CV) was slightly different (P = 0.042) between Sorted and Unsorted pigs (13.3 and 15.6%, respectively), at the end of the study. Thus, sorting nursery pigs by BW did not improve growth performance and also, induce a lag of post-weaning feed intake onset and increased fights in Heavy pigs.

Exigência de aminoácidos sulfurados digestíveis para suínos machos castrados mantidos em ambiente termoneutro dos 15 aos 30kg / Digestible sulphurous aminoacid requirement for swine barrows maintained in a thermoneutral environment from 15 to 30kg

Determinou-se a exigência de aminoácidos sulfurados para suínos machos castrados, mantidos em ambiente termoneutro, dos 15 aos 30kg. Utilizaram-se 70 leitões mestiços, distribuídos em delineamento experimental de blocos ao acaso, com cinco tratamentos (0,465; 0,511; 0,558; 0,605 e 0,652 por cento de metionina + cistina digestível), sete repetições e dois animais por repetição. As rações experimentais e a água foram fornecidas à vontade. A temperatura no interior da sala foi mantida em 21,8±0,4ºC e a umidade relativa, em 73,8±4,9 por cento. Os níveis de metionina + cistina digestível da dieta influenciaram de forma quadrática o ganho de peso diário, que aumentou até o nível de 0,596 por cento, e a conversão alimentar, que reduziu até o nível de 0,627 por cento. O consumo de ração dos animais não variou com os tratamentos. Os tratamentos influenciaram a deposição de proteína na carcaça, que aumentou de forma quadrática até o nível de 0,630 por cento, enquanto a de gordura não variou. A exigência de aminoácidos sulfurados digestíveis para suínos machos castrados, mantidos em ambiente termoneutro, dos 15 aos 30 kg, é de 0,63 por cento, correspondente à relação metionina + cistina digestível:lisina digestível de 67 por cento, para máximo desempenho e composição de ganho.