Evaluation of various grueling protocols
What's the impact on nursery pig performance and survivability?
By Carly Bates, Brandi Burton, Amanda Reever and Jeff Okones
Proper post-weaning nutrition is critical, especially when considering pigs that have undergone transport stress and environmental changes. Previous work has shown that weaning causes morphological and functional changes of the small intestine of pigs where majority of the nutrients are digested and absorbed and these changes can result in severe diarrhea and possibly mortality1.
Grueling is the technique of mixing water into feed and has long been used to aid weaned pigs in the transition from a milk-based diet to a solid feed diet. Grueling is commonly seen in pull pens or pens that contain fall back/health challenged pigs that have been removed from the general population with a smaller stocking density. According to Mark Bertram2 gruel fed is best fed multiple times throughout a day to mimic the activity of nursing. Many producers have adopted gruel feeding as a daily chore post-placement; however, it is likely that it is under-fed by most caretakers and grueling protocols are not well documented in the industry today.
To best utilize this practice, it is important to understand proper gruel volume, ratios, frequency, feeder space and production impact of different techniques that can be used by producers to ensure proper gruel efficacy.
Our objective was to evaluate weight gain and mortality differences in pull pen pigs that received gruel according to two protocols compared to a negative control group.
Materials and methodsThe study was conducted in a 3,600 head nursery with three rooms in Eastern Iowa. There were three treatment groups involved in this study treatment 1, 2 and 3. After each room filled, pigs were thoroughly evaluated at 1-, 3-, 7-, and 10-days post placement to determine which pigs needed pulled from general population and enrolled in the study.
Pigs were included in the study if they showed signs of severe lameness, had a low body condition score (spine/hip bones exposed), were significantly smaller than their pen mates, or appeared unthrifty. On each pull day, pigs were identified and then randomly allotted to a treatment using a random list generator application.
Pigs were then tagged with individual RFID, weighed and placed in their appropriate pen. At least six pens per room were designated for the trial (one per pull day for treatment 1, one pen for treatment 2, and one pen for treatment 3).
Treatment 1 pull pens contained only pigs that were pulled on a single day (one pen per pull day per room) with no continuous addition of other pigs after the original group was allotted and placed. The smaller pen size was derived from previous studies that have shown average daily gain (ADG) improves with a smaller group size3. These pigs were gruel fed 0.1 pounds of feed per pig per day over three feedings each day with proper water ratios that started at 75% water and declined to 25% water over seven days (Figure 2). The gruel was fed out of a four-foot trough that ensured at least three inches of space per pig.
Treatment 2 pull pens had continuous addition of pigs to the pen on all pull days (one pen per room). They received 0.1 pounds of feed per pig with equal amounts of water one time each day for seven days. The gruel was fed in a circular feeder with a 52-inch circumference. If the pen exceeded 40 pigs, another identical feeder was added.
Treatment 3 pull pens had continuous addition of pigs to the pen on all pull days (one pen per room). They received no gruel and acted as the negative control group.
All pens had access to normal dry feed and water as general population had. If any single pen exceeded 55 pigs, an additional pen was added for that group. If any pig enrolled in the study died, its ear tag was cut out and date was recorded through the end of the turn. Pigs that are determined to be a cull pig will be individually identified as well.
All treatments, vaccine and daily production was done on trial as needed as the caretakers would on a normal basis. At the end of the nursery phase, pigs were weighed, and ADG was calculated. Death dates and mortality reasons were also recorded and mortality was calculated.
Pigs were followed through the finisher phase to better understand the lasting impact gruel feeding as. Numerical observations, rather than statistical, were analyzed due to the design of the study.
ResultsThere were large numerical differences identified between piglet treatments and mortality percentage (Figure 1). No ADG differences were shown to correlate between treatment groups. The difference in mortality percentages between treatment 1 and the control group suggests that grueling several times per day with proper ratios can drastically increase survivability in nursery pigs.
This study successfully generated data to support two grueling options that will have immediate impact on nursery pigs in many systems and environments. When comparing the full-value market pig percentages between the three treatment groups there was noticable differences (Figure 3).
There was a numerical trend of increasing percentage full-value pigs based on treatment group; treatment 1 had over 10% more full-value pigs than the control group and a near 7% difference compared to treatment 2
DiscussionPull pigs are a subjective measure that can differ between producers, managers and caretakers, setting guideline for each operation is the beginning to implementing proper gruel management. With the current lack of documentation regarding gruel feeding in a nursery setting, this study helped to better the detail on what can be done as producers to better manage mortality and increase survivability.
Although this trial did not show any significant data for ADG, it shows a strong indication that the addition of gruel feeding will impact mortality significantly. This data is applicable to both nursery and wean-to-finish sites with easy implementation and low-cost effect for producers.
References1Zheng, Lan, et al. “Intestinal Health of Pigs upon Weaning: Challenges and Nutritional Intervention.” Frontiers, Frontiers, 1 Jan. 1AD,
2Bertram, Mark J. “Implications of Early Post-Weaning Management on Subsequent Performance of Piglets.” Swine Information Library Access Restricted, Nov. 2014, https://www.aasv.org/library/swineinfo/item.php?ISU%2F2014%2F125.pdf.
3Smith, Laura F, et al. “The Impact of Feeder Adjustment and Group Size-Floor Space Allowance on the Performance of Nursery Pigs.” Swine Information Library Access Restricted, June 2004, https://www.aasv.org/library/swineinfo/item.php?SHAP%2F2004%2Fv12n3p111.pdf.
Bates is a student at Iowa State University’s College of Veterinary Medicine, Burton and Reever are veterinarians with Suidae Health and Production, and Okones is a veterinarian with Pharmgate Animal Health.
