Piglet mortality – A parallel comparison between loose-housed and temporarily confined farrowing sows in the same herd

Figures & data

Figure 1. Over-view of the two farrowing systems compared in the study. Picture A- TC-pen in which sows were temporarily confound at farrowing + movable heating lamp behind the sow. Picture B- TC-pen in which sows were loose 3 days after farrowing. Picture C- L-pen with loose sows at farrowing and during the whole lactation period.

Table 1. Template used to classify causes of death of live-born piglets.

Cause of death (recordings in the herd)	Description	Cause of death (after merging death causes in the statistical analyzes)
Underweight at birth	Piglets, ≤900 g at birth, dead due to starvation, crushing or euthanasia since they were unable to cope due to underweight.	Underweight
Starvation	Piglets, dead due to starvation but without signs of underweight, weakness, splay-leg problems or malformation.	Starvation
Crushing	Piglets, which died or had to be euthanized due to crushing of the sow without earlier, recorded disabilities.	Crushed by the sow
Weak or splay-leg at birth	Piglets, dead due to starvation, crushing or euthanasia since they were unable to cope due to weakness or splay-leg problems (>900 grams).	Others
Malformation at birth	Piglets, dead due to starvation, crushing or euthanasia since they were unable to cope due to malformation.	Others
Diarrhea	Piglets, dead due to clear signs of diarrhea.	Others
Joint/claw inflammation	Piglets, which had to be euthanized due to not recovering after treatment of joint/claw inflammation with antibiotics.	Others
Bitten to death	Piglets, which were bitten to death by the sow	Others
Others	Used when not possible to identify any of the other death causes above.	Others

Table 2. Template used to classify morbidity/treatments in the sows.

Treatments/morbidity in the sows (recordings in the herd)	Treatments/morbidity in the sows (after merging recordings in the statistical analyzes)
Farrowing problems (assistance needed)	Farrowing problems
MMA (mastitis, metritis, agalactia)	MMA
Failure of milk let down	Others
Udder inflammation (not associated with farrowing)	Others
Joint inflammation	Others
Claw abscess	Others
Lameness	Others
Reduced appetite	Others
Shoulder lesion	Others
Others	Others

Table 3. Template used to classify treatments/morbidity in the piglets.

Treatments/morbidity in the piglets (recordings in the herd)	Treatments/morbidity in the piglets (after merging recordings in the statistical analyzes)
Piglet diarrhea (0–7 days)	Piglet diarrhea
Claw abscess/(joint inflammation)	Claw abscess
Middle ear inflammation/meningitis	Others
Diarrhea during the latter part of the suckling period (>7 days)	Others
Lesions	Others
Others	Others

Figure 2. Number of dead piglets per litter within different litter sizes and with specified causes of death.

Table 4. Overview of litters, production results and mortality in the study.

Age of sow, parity	Total	1 + 2	3 + 4	≥5
No. of litters in the study, total	321
No. of litters deleted from the study	3^a
No. of litters left in the study	318	127	120	71
No. of piglets ‘at risk’	4564	1797	1695	1072
No. per litter
Total born	15.1	14.4	15.0	16.8
Stillborn	0.8	0.6	0.9	1.1
Live-born	14.3	13.9	14.1	15.6
‘At risk’	14.3	14.1	14.1	15.1
Dead before weaning	3.0	2.3	2.9	4.3
Weaned	11.3	11.8	11.2	10.8
Causes of death, no. of piglets per litter
Underweight	1.1	0.8	0.9	1.9
Crushed by the sow	1.1	0.8	1.2	1.4
Starvation	0.2	0.2	0.3	0.3
Other	0.6	0.6	0.5	0.7

^aOne sow died during farrowing and two sows farrowed before confinement in system TC.

Table 5. Number of total born, live born, ‘at risk’, dead before weaning and weaned (mean ± std).

	Farrowing system		p-value
	Temporarily confined (TC)	Loose (L)	Farrowing system	Age category
No. of litters	157	161
No. per litter
- total born	15.3 ± 3.9	15.0 ± 3.8	0.23	0.008**
- stillborn	0.8 ± 1.2	0.8 ± 1.3	See Table 6
- live-born	14.5 ± 3.6	14.2 ± 3.4	0.20	0.03*
- ‘at risk’^a	14.4 ± 2.7	14.3 ± 2.5	0.51	0.07
- dead before weaning	2.8 ± 2.4	3.8 ± 2.8	See Table 6
- weaned	11.6 ± 1.9	11.1 ± 2.1	0.03*	<0.001***

^aTransfer of piglets was always made within system but sometimes to/from sows not in the study.

Effect of farrowing system and age category; in all tests in the table, the interaction was not significant.

Table 6. Preweaning mortality. Cause of death, age and percent of piglets per litter, which died before weaning (lsmeans ± SE).

	Farrowing system		p-value
	Temporarily confined (TC)	Loose (L)	Farrowing system	Age category
No. of litters	157	161
Stillborn, % of total born piglets per litter	4.0 ± 0.6	4.7 ± 0.6	0.26	0.13
Preweaning mortality, % of ‘at risk' piglets per litter
Day 1–3
- underweight	4.1 ± 0.5	5.3 ± 0.6	0.04*	0.04*
- crushed by the sow	2.6 ± 0.4	5.2 ± 0.6	Interaction
parity 1 + 2	2.8 ± 0.6	3.3 ± 0.7	0.57
parity 3 + 4	1.9 ± 0.6	6.6 ± 1.0	<0.001***
parity ≥5	3.3 ± 0.8	6.5 ± 1.2	0.03*
- starvation^a	-	-
- others	0.4 ± 0.2	0.8 ± 0.3	0.12	0.30
Whole preweaning period
- underweight	5.9 ± 0.7	6.5 ± 0.7	0.40	0.002**
- crushed by the sow	5.8 ± 0.6	7.6 ± 0.7	Interaction
parity 1 + 2	5.6 ± 0.9	5.2 ± 0.9	0.77
parity 3 + 4	5.0 ± 0.9	10.1 ± 1.2	0.001***
parity ≥5	7.0 ± 1.2	8.6 ± 1.4	0.39
- starvation	1.6 ± 0.4	1.5 ± 0.4	0.77	0.12
- others	3.7 ± 0.6	4.0 ± 0.6	0.75	0.84

^aThe number of piglets starved to death day 1–3 is not enough to find a suitable model.

Effect of farrowing system and age category; if only p-values for main effects are given, the interaction was not significant.

Table 7. Actual and estimated farrowing duration (h) (mean ± SE).

	Farrowing system		p-value
	Temporary confined (TC)	Loose (L)	Farrowing system	Age category
Actual time registration
No. litters	49	46
Farrowing duration, h	4.5 ± 0.2	4.2 ± 0.2	0.32	0.92
Estimated time registration
No. litters	91	98
Farrowing duration, h	4.8 ± 0.1	4.8 ± 0.1	0.85	0.45

Effect of farrowing system and age category.

Table 8. Morbidity/treatments in sows and piglets. Percent of pens with morbidity/treatments.

	Farrowing system		p-value
	Temporarily confined (TC)	Loose	Farrowing system	Age category
No. of litters	157	161
No. of special notes	2^a	0
Morbidity/treatments in sows, % of pens
- farrowing problems	4.5	0.6	0.03*	0.48
- MMA	4.5	9.3	0.12	0.01*
- others	1.9	5.0	0.22	0.18
Morbidity/treatments in pigs, % of pens
- piglet diarrhoea	8.9	10.6	0.45	0.41
- claw abcess	48.4	55.9	0.31	0.03*
- others	9.6	16.8	0.07	0.36

^aTwo TC sows had special notes on their sow journals of ‘restless at confinement’.

Effect of farrowing system and age category. Due to the small number of events, this was analyzed with Fisher’s exact test.