The Effect of Needle Reuse on Piglet Skin Puncture Force

Abstract

The study investigated whether the repeat use of needles used to inject piglets with iron, influences the force required to puncture into piglet cadaver skin. Pig units (n = 31) were surveyed on needle reuse and injection practices, and these findings informed subsequent laboratory-based experiments on needle puncture force into piglet cadaver tissues. A 21 G 5/8" needle was reported as the most used needle type (67.7%), with 80.6% reporting needle reuse; 38.7% changed the needle between litters or earlier if damaged, 16.1% every three litters and 22.5% when it felt blunt or damaged, after each injection session or when changing the bottle of iron solution. There was a significant difference in puncture force between the 1st and 36th use (p < 0.05), and between the 1st and 100th use (p = 0.0015), but not between the 1st and 12th or 36th use (p > 0.999 and p = 0.8313, respectively). Scanning electron microscopy (SEM) imaging showed appreciable damage to the needle tip after 12 uses. The repeat use of needles in piglet cadavers increased the force of needle puncture compared to first-time use. When extrapolated to live animals, the use of blunt needles has the potential to cause pain and distress.

Keywords: animal welfare; needle reuse; piglet skin; puncture force; scanning electron microscopy.

Figure 1

Mecmensin Advanced Force Gauge (AFG 100 N) meter used in puncture studies.

Figure 2

Piglet cadaver positioned with needle attachment directly above the neck injection site (dotted triangle).

Figure 3

Needles mounted on aluminium specimen stubs with Leit-C to form a conducting strip from the base of the hub to the needle shaft.

Figure 4

Experiment 1. Puncture force (N) into piglet cadaver for 1st puncture (n = 18) and artificially blunted (n = 17) 21 G needles. *** p < 0.0001 compared to 1st puncture.

Figure 5

Experiment 2. Puncture force (N) into piglet cadaver for ×1A, ×1B and ×36A 21 G needles and ×1 18 G control needles (n = 10 needles per group). ** p = 0.0023 compared to ×1A, *** p < 0.0002 compared to ×1A.

Figure 6

Experiment 3. Puncture force (N) into piglet cadaver for ×1A, ×1B and ×36A (n = 9 per group) and control 21 G needles (blunted by puncture into chamois leather) (n = 6). ** p = 0.0111 compared to ×1A, *** p = 0.0053 compared to ×1A.

Figure 7

Experiment 4. Puncture force (N) into piglet cadaver for 1st, 12th, 36th or 100th puncture of 21 G needles (n = 7 per group) and control 21 G needles (blunted by puncture into chamois leather) (21 G C), (n = 6) and control 18 G needles (18 G C), (n = 3). * p = 0.0015 compared to ×1, ** p = 0.0017 compared to ×1, *** p = 0.0041 compared to ×1.

Figure 8

SEM images of two unused 21 G needles (Needle 1 and Needle 2). Image (A): Needle 1 (magnified ×750), Image (B): Needle 1 (magnified ×1000), Image (C): Needle 2 (magnified ×200), Image (D): Needle 2 (magnified ×1000).

Figure 9

SEM images of select needles from Experiment 3 together with the puncture force (N) measured upon injection into a piglet cadaver tissue. Needle 1, ×1 use, puncture force 0.54 N; Needle 2, ×1 use, puncture force 0.48 N; Needle 3, ×36 use, puncture force 0.80 N; Needle 4, ×36 use, puncture force 0.80 N. Image (A): Needle 1, ×1 use (magnified ×200); Image (B): Needle 1, ×1 use (magnified ×1000); Image (C): Needle 2, ×1 use (magnified ×200); Image (D);: Needle 2, ×1 use (magnified ×1000); Image (E): Needle 3, ×36 use (magnified ×200); Image (F): Needle 3, ×36 use (magnified ×1000); Image (G): Needle 4, ×36 use (magnified ×200); Image (H): Needle 4, ×36 use (magnified ×1000).

Figure 10

SEM images of select needles from Experiment 4 together with the puncture force (N) measured upon injection into a piglet cadaver tissue. Needle 1, ×1 use, puncture force 0.60 N; Needle 2, ×1 use, puncture force 0.70 N; Needle 3, ×12 use, puncture force 0.90 N; Needle 4, ×12 use, puncture force 0.90 N; Needle 5, ×36 use, puncture force 0.94 N; Needle 6, ×36 use, puncture force 0.94 N; Needle 7, ×100 use, puncture force 1.28 N; Needle 8, ×100 use, puncture force 1.32 N. Image (A): Needle 1, ×1 use (magnified ×750); Image (B): Needle 1, ×1 use (magnified ×1000); Image (C): Needle 2, ×1 use (magnified ×200); Image (D): Needle 2, ×1 use (magnified ×1000); Image (E): Needle 3, ×12 use (magnified ×200); Image (F): Needle 3, ×12 use (magnified ×1000); Image (G): Needle 4, ×12 use (magnified ×169); Image (H): Needle 5, ×36 use (magnified ×750); Image (I): Needle 5, ×36 use (magnified ×1000); Image (J): Needle 6, ×36 use (magnified ×200); Image (K): Needle 5, ×36 use (magnified ×1000); Image (L): Needle 7, ×100 use (magnified ×200); Image (M): Needle 7, ×100 use (magnified ×1000); Image (N): Needle 8, ×100 use (magnified ×200); Image (O): Needle 8, ×100 use (magnified ×1000).

Figure 10

SEM images of select needles from Experiment 4 together with the puncture force (N) measured upon injection into a piglet cadaver tissue. Needle 1, ×1 use, puncture force 0.60 N; Needle 2, ×1 use, puncture force 0.70 N; Needle 3, ×12 use, puncture force 0.90 N; Needle 4, ×12 use, puncture force 0.90 N; Needle 5, ×36 use, puncture force 0.94 N; Needle 6, ×36 use, puncture force 0.94 N; Needle 7, ×100 use, puncture force 1.28 N; Needle 8, ×100 use, puncture force 1.32 N. Image (A): Needle 1, ×1 use (magnified ×750); Image (B): Needle 1, ×1 use (magnified ×1000); Image (C): Needle 2, ×1 use (magnified ×200); Image (D): Needle 2, ×1 use (magnified ×1000); Image (E): Needle 3, ×12 use (magnified ×200); Image (F): Needle 3, ×12 use (magnified ×1000); Image (G): Needle 4, ×12 use (magnified ×169); Image (H): Needle 5, ×36 use (magnified ×750); Image (I): Needle 5, ×36 use (magnified ×1000); Image (J): Needle 6, ×36 use (magnified ×200); Image (K): Needle 5, ×36 use (magnified ×1000); Image (L): Needle 7, ×100 use (magnified ×200); Image (M): Needle 7, ×100 use (magnified ×1000); Image (N): Needle 8, ×100 use (magnified ×200); Image (O): Needle 8, ×100 use (magnified ×1000).