MAKE SURE PIGS HAVE ENOUGH WATER IN SUMMER

Water is not only essential for swine survival, it is also a critical nutrient for growth, maintenance of pregnancy, and weight gain during lactation. In hot weather, the pig’s dependence on water to keep cool and maintain performance becomes even more critical. With summer upon us, consider taking time to assess your operation’s watering situation.

Addressing the pig’s water needs can be done from a supply and demand perspective. If enough good quality water is supplied to meet the pig’s biological needs, performance will not suffer. But if the pig’s demand for water exceeds the available supply, the pig will not grow and develop to its genetic potential. However, supplying water to the growing pig can be confounded by the need to reduce the amount of liquid entering the manure management system.

Temperature greatly influences the pig’s water needs as pigs use water to help reduce body heat. When the environmental temperature rises from 59 to 95 degrees, the water needs of a 75-pound pig can increase by 57 percent and that of a 250-pound pig increases 63 percent.

Water systems should be checked regularly for any signs of contamination. The quality of the water may affect intake, nutrient digestibility, and pig performance. Total dissolved solids (TDS) should not exceed 6,000 to 7,000 ppm. The mineral content and microbial safety of your water source should be routinely monitored. In-line filters and traps can help improve water quality on some farms.

Watering devices should be maintained frequently to prevent leaks, screens should be cleaned, and adequate flow to the pig should be assured. The recommended flow from a nipple drinker is 750 ml/minute for a growing pig and 1,000 ml/minute for a finishing pig. Flow rate can be checked by using a measuring container to collect the water flowing from drinkers for one minute and comparing it to the recommended rate for the age of pig and type of waterer.

Pigs will remain at waterers for only a limited amount of time. This means there must be an adequate number of waterers available per pen and the flow rate must be adequate to satisfy the pigs’ needs quickly.

Note that stray voltage on watering devices frequently limits water intake. This electrical charge can be measured with a good voltmeter and an isolated ground. As little as 0.5 to 1 volt may reduce pigs’ water intake under certain conditions. Check with your electric utility supplier for assistance.

Gate-mounted nipple waterers should be adjusted frequently to a height just above the pigs’ shoulders to prevent injuries and carcass bruising. Also, the screens in your watering devices should be cleaned regularly. Dirty filters restrict water flow, and pigs need to quench their thirsts quickly.

Consider replacing older equipment with water-saving drinkers. Standard fixed nipple waterers tend to result in excessive water waste, especially during warm weather. Swinging nipple waterers may reduce water use by 10 to 25 percent, compared to fixed nipples. Some modern bowl type nipple drinkers may reduce water disappearance by 20 to 35 percent, compared to standard fixed nipples. Integrating the drinker nipple into the feeder (wet/dry type) has resulted in a 33 percent reduction in liquid manure production, which equates to reduced waste of water and feed combined.

Table 1. Water flow requirements

—Todd See

THREE RESEARCH SUMMARIES

Swine research reports from around the world were presented at the March meeting of the Midwestern Section of the American Society of Animal Science in Des Moines, Iowa. The following is a summary of some of those reports, which may have practical implications that are ready to be implemented at the farm level.

Cross-fostering
Researchers from South Dakota State University designed a study to test the hypothesis that cross-fostering of pigs while nursing will reduce within-litter weight variation of piglets at weaning. They practiced cross-fostering to form two litter sizes (9 or 12 pigs) and created litters that consisted of light piglets, heavy piglets, or piglets of variable weights. This project used 107 litters, and all cross-fostering occurred within 48 hours of birth. Piglets were individually weighed at 7, 14, 21, and 28 days of age, and the standard error and coefficient of variation were calculated to assess within-litter size variation. Their results showed that the differences in total piglet weight and average daily gain of the litters remained constant throughout the experiment for the light, heavy, and variable litters. However, piglets raised in 9-pig litters were 0.86 pounds heavier than those raised in 12-pig litters (P < 0.001) at weaning. At the time of cross-fostering, the standard error and coefficient of variation of the variable weight litter were greater than the light and heavy litter groups. However, by days 14, 21, and 28, no significant differences were detected in piglet weight variation within litter. These results would indicate that cross-fostering to create litters of uniform piglets at birth does not reduce the variability of weight of piglets at weaning.

Loading Distance, Crowding
A team including researchers from the University of Illinois, Maschoffs Inc., and ELANCO Animal Health presented results from a study designed to evaluate the effects of distance moved during loading and floor space provided during transport on pig losses at the packing plant. The study involved 42 loads of pigs that had either a short (0 to 100 feet) or long (200 to 300 feet) loading distance from the barn to the truck that were then provided six levels of floor space (4.25, 4.5, 4.7, 5, 5.25, and 5.6 square feet per pig) during transportation. Standard procedures were used for loading and unloading, and transport time to the plant was approximately 3 hours. Pigs that were moved the long distances during loading had a higher incidence of open-mouthed breathing during loading and tended to have a higher percentage of nonambulatory pigs during loading (0.32 vs. 0.08%; P = 0.09) and at the plant (0.24 vs. 0.04%; P = 0.06). However, loading distance did not affect other losses at the plant. Total losses at the plant were greatest for the three lowest floor spaces, compared to the two highest floor spaces (2.2 vs. .56%; P < 0.05), indicating that floor space during transport has a major impact on loss at the plant.

Weaning to Ovulation
Two University of Illinois researchers reported on a project that characterized factors that influenced the variation in weaning-to-ovulation interval. Determination of factors influencing the weaning-to-ovulation interval may allow for improved success with fixed-time inseminations. This was a retrospective analysis of 7 studies that partitioned 786 sows into groups that received PG600 (n=136) at weaning or not (n=650) and sows receiving GnRH at onset of estrus (n=238) or not (n=548). The weaning-to-ovulation interval was normally distributed with a mean of 6 days. Eighty-five percent of sows ovulated on day 5 to 6.5, 5 percent ovulated on day 2 to 4.5, and 10 percent ovulated on day 7 to 10 after weaning. Administration of PG600 advanced the weaning-to-ovulation interval and skewed the distribution (P < 0.001). Administration of GnRH at the onset of estrus did not affect the weaning-to-ovulation interval. Weaning-to-ovulation intervals were shorter in the spring and summer, compared to fall and winter. Parity of the sow and the average size of the largest follicles at estrus did affect weaning-to-ovulation interval. However, weaning-to-ovulation intervals were shortened (P < 0.01) for lactation lengths greater than 18 days and were more variable for lactation lengths of less than 18 days. The results suggest that ovulation time from weaning is less variable than predicting ovulation time based on estrus. Also, if timed insemination protocols are developed, adjustments will be needed to correct for variation due to gonadotropin treatment, season, and lactation length.

—Todd See