Managing the lactating sow for optimal weaning and rebreeding performance

Goodband R, Gebhardt JT. Effect of different sow lactation feeder types and drip cooling on sow bodyweight, litter performance, and feeder cleaning criteria

A total of 600 sows (line 3; PIC, Hendersonville, TN) were used to evaluate the effect of different lactation feeder types and drip cooling on sow farrowing performance and litter growth performance during the summer. For the feeder evaluation, the trial was conducted in two sequential groups with 300 sows per group. Five 60-farrowing-stall rooms with tunnel ventilation were used for each group. On approximately days 110 to 112 of gestation, sows were blocked by body condition score (BCS), parity, and offspring sire (lines 2 or 3 sires; PIC), then randomly allotted to one of three feeder types: 1) PVC tube feeder, 2) Rotecna feeder (Rotecna), or 3) SowMax feeder (Hog Slat). The three feeder types were placed in one of three stalls with the same sequence from the front to the end of all rooms to balance for environmental effects. For drip cooling evaluation, the trial was conducted during the 2nd group of 300 sows. Drippers were blocked in three of every six farrowing stalls to balance feeder type and environmental effects. After farrowing, sows had ad libitum access to feed. For litter performance data, only pigs from sows bred to line 2 sires were recorded. Line 3 sire pigs were not included in litter performance data, but sows of these pigs were included in sow body weight (BW) and feed disappearance data. After weaning, feeder cleaning time was recorded on a subsample of 67 feeders (19, 23, and 25 for PVC tube, Rotecna, and SowMax, respectively). There was no evidence of difference (P > 0.05) in sow entry BW, exit BW, BW change, and litter performance among the different feeder types. However, sows using the SowMax feeders had decreased (P < 0.05) total feed disappearance, average daily feed disappearance, and total feed cost compared to those fed with the PVC tube feeders. There was a marginal difference (P < 0.10) between feeder types in cleaning time, with PVC tube feeders requiring less time than the Rotecna feeders; however, cleaning time varied greatly between the personnel doing the cleaning. Sows with drip cooling had greater (P < 0.05) feed disappearance, litter growth performance, and subsequent total born, and reduced (P < 0.05) BW change. In conclusion, using a SowMax feeder reduced feed disappearance with no effects on sow and litter performance compared to a PVC tube feeder, and drip cooling improved sow and litter performance during summer.

The influence of parity order and body condition and serum hormones on weaning-to-estrus interval of sows

This study was performed to investigate the weaning-to-estrus interval (WEI) in primiparous and multiparous sows in relation to their weight and back-fat thickness changes and serum hormone imbalance (insulin, growth hormone, and cortisol) at the end of gestation and during lactation. Ten primiparous and ten multiparous Camborough sows, fourth to seventh parity, were used in this experiment. During gestation, daily food intake was 2.4 kg (sow commercial diet: 2.96 Mcal/kg, 16% crude protein) and during lactation all sows were fed on a wet commercial diet (3.34 Mcal/kg, 17% crude protein) ad libitum, three times per day. Blood samples were collected and back-fat thickness at the P(2) site were recorded at 6 days before and 2, 7, 14, 21 and 25 days after farrowing. Body weight was recorded on the same dates, except the date before farrowing. The WEI was also recorded. The average daily feed intake was different (P<0.05) between primiparous and multiparous sows during lactation (5.23 versus 5.72kg per day, respectively). There was a difference (P<0.05) between primiparous and multiparous sows in total percentage of back-fat thickness loss from the end of gestation until weaning (-20.18 and -9.03%, respectively). The total percentage of weight loss during lactation was slightly greater (P>0.05) in multiparous than primiparous sows. Weaning-to-estrus interval was greater (P<0.05) in the primiparous group when compared with the multiparous group (5.55 and 4.22 days, respectively). No differences were found in insulin, growth hormone (GH), and cortisol concentrations between parity groups, except on the 21st day of lactation, when GH was greater in primiparous sows. There was no correlation between percentage of total weight loss and WEI, or percentage of back-fat thickness loss (total or by periods) and WEI. There were positive correlations between GH serum concentration on the 14th and 21st days and the percentage of weight loss in the third week of lactation (r=0.46, P<0.04 and r=0.52, P<0.02, respectively), and between GH concentration on the 21st and on weaning days and WEI (r=0.54, P<0.02 and r=0.42, P<0.06, respectively). Our results indicate that the hormone change (imbalance) during lactation, mainly GH, seems to be a better parameter to explain the difference in WEI between primiparous and multiparous sows than change in body condition.