Clinical case: Diffuse reproductive problems in high health conditions

Farm description

It is a 17000-sow Brazilian farm, PRRS negative, with internal replacements and no introduction of animals from outside.

Case onset

The problem does not appear suddenly, the farm owner points out two main problems:

• Historically, low general prolificacy.
• A decline in performance in recent months, but without a specific parameter being affected. According to the farmer, “the sows performance is worse in general terms."

Case analysis

First, we analyse the historical production data of the farm, to quantify the two areas the owner mentioned and to detect possible trends or temporal variations.

Table 1. Analysis of productive trends, 6 periods of 12 months.

	1/4/2010 31/3/2011	1/4/2011 31/3/2012	1/4/2012 31/3/2013	1/4/2013 31/3/2014	1/4/2014 1/3/2015	1/4/2015 31/3/2016	Total	Average
Total No. of services	4,252	4,364	4,479	4,490	4,583	4,568	26,736	4,456
Repeat services	287	273	372	298	295	319	1844	307
Percent repeat services	6.7%	6.3%	8.3%	6.6%	6.4%	7.0%		6.9%
No. of farrowings (litters)	3600	3848	3808	3853	3966	4105	23180	3863
Total piglets born	46,468	51,488	50,806	52,529	53,024	53,165	30,7480	51,247
Average Total born/litter	12.9	13.4	13.3	13.6	13.4	13.0		13.3
Total pigs born alive	41,667	47,049	46,557	47,694	47,712	48,149	278,828	46,471
Average born alive/litter	11.6	12.2	12.2	12.4	12.0	11.7		12.0
Total Stillborn	2,602	2,417	2,369	3,212	3,928	3,520	18,048	3,008
(% of Total born)	5.6%	4.7%	4.7%	6.1%	7.4%	6.6%	5.9%
Total mummified	2,199	2,022	1,880	1,623	1,384	1,496	10,604	1,767
(% of Total born)	4.7%	3.9%	3.7%	3.1%	2.6%	2.8%	3.4%
Farrowing rate	88.8%	88.1%	85.3%	86.1%	88.1%	88.4%		87.5%
Pre-weaning deaths	3,504	3,709	2,937	3,303	2,854	2,952	19,259	3,210
(% of born alive)	8.4%	7.9%	6.3%	6.9%	6.0%	6.1%		6.9%
Weaned sows	3,634	3,857	3,776	3,833	3,966	4,120	23,186	3,864
Total weaned piglets	38,284	43,135	43,143	43,819	43,883	42,999	255,263	42,544
Pre-weaning mortality	8.7%	8.6%	6.5%	7.5%	8.5%	10.8%		8.4%
Pigs weaned /litter weaned	10,5	11,2	11,4	11,4	11.1	10.4		11.0
Average age at weaning	23.2	21.4	21.3	20.6	19.5	19.5		20.9
Sow inventory
Average No. of females	1,912	2,024	1,980	2,022	1,953	1,974		1,978
Average No. of gilts	377	407	340	390	284	265		344
Average No. of sows	1,535	1,617	1,640	1,632	1,669	1,709		1,634
Average female age (parity)	2.1	1.7	1.8	2.0	2.2	2.3		2.0

The data confirm the owner's information:

• The overall prolificacy of the farm has always been low, although it has recently dropped by practically half a piglet compared to previous periods.
• Performance in the farm has worsened, not generally, but specifically in the farrowing house, and mainly related to a pre-weaning mortality increase.

The following are also evident:

• During the last 5 years, the average parity has increased, from 1.7 litters to the current 2.3. This fact can have an influence on several productive parameters.
• Parallel to the slow but progressive increase in farm size, lactation length has dropped from 23.2 days, 6 years ago, to the current 19.5. Logically, this reduction may have an effect on prolificacy, which will be discussed again later.

Low prolificacy

The study of this parameter is based mainly on productive data analysis. The distribution by parity number of the total born in the last 12 months is as follows:

The graph shows that prolificacy goes down clearly after the first lactation. In fact, although gilts are usually one of the groups with less prolificacy, theirs prolificacy is, on average, almost equal to the global one. Therefore, the problem seems to be concentrated in the multiparous sows. Since lactation length has been decreasing, the effect of this lactation length on subsequent prolificacy is being analysed.

Table 2.Mating results by previous lactation length, April 10-March 16

	Total serv.	Matings per serv.	Repeat. %	Average age of sows (parity)	Farr. rate	Concep. rate	Av. Born alive	Av. Stillborn	Av. Total born	Av. weaned	% more 125 days
18 days	501	1.7	8.8%	2.1	82.4%	86.2%	11.2	0.8	12.4	10.8	95.2%
19 days	1,109	1.7	11.1%	2.4%	80.7%	83.0%	11.5	0.7	12.6	10.8	97.4%
20 days	1,872	1.6	9.1%	2.5	82.2%	85.8%	11.8	0.8	12.9	11.0	96.2%
21 days	4,761	1.6	8.1%	3.2	84.5%	87.8%	12.0	0.9	13.2	10.6	96.2%
22 days	4,799	1.4	6.6%	3.3	81.8%	88.1%	12.2	0.8	13.5	10.8	93.0%
23 days	2,240	1.2	8.8%	2.9	83.7%	86.0%	12.3	0.7	13.5	11.0	97.5%
24 days	987	1.1	10.0%	2.5	82.0%	84.2%	12.1	0.7	13.3	11.2	97.5%
25 days	527	1.1	10.6%	2.3	84.6%	85.0%	11.9	0.6	12.9	11.0	99.1%
26 days	438	1.0	13.9%	2.4	81.5%	82.5%	12.2	0.5	13.3	11.2	99.1%
Total	18,922	1.4	8.5%	2.9	82.9%	86.5%	12.0	0.8	13.2	10.8	98.1%
Standard deviation		0.64		1.72			3.37	1.32	3.63	3.51

Between 18 and 23 days, the difference is more than one piglet. Therefore, the short duration of lactation is one of the causes of low prolificacy, and this effect has increased in recent periods, as lactation length has decreased.

On the other hand, the farm has, in addition to the GP sows, two different genetic lines. Prolificacy is analysed by parity of both genetic lines.

Genetics B has clearly lower prolificacy than genetics A. Therefore, genetics B is clearly penalizing global prolificacy. This graph also shows an important finding, ie, that in both genetic lines, the first farrowing is one of the most prolific, reinforcing the hypothesis of prolificacy problems associated to multiparous sows.

Last year decrease

Table 1 shows that the reduction in efficiency in the last period was mainly due to an increase in pre-weaning mortality. However, further analysis of the gestation data shows that parameters such as irregular repeats and abortions have increased in this last period over the previous three.

Table 3.Gestation results, 6 periods of 12 months.

	01-apr-10 31-mar-11	01-apr-11 31-mar-12	01-apr-12 31-mar-13	01-apr-13 31-mar-14	01-apr-14 31-mar-15	01-apr-15 31-mar-16
Total services	1,719	3,538	4,418	4,485	4,577	4,565
(as total % )	7.4%	15.2%	19.0%	19.2%	19.6%	19.6%
Return services	119	233	370	299	295	319
Return rate	6.9%	6.6%	8.4%	6.7%	6.4%	7.0%
Av. return interval	26.1	26.4	23.6	26.1	31.9	26.3
Early returns (<18)	2	6	1	6	0	4
Regular return -1ª (18-25)	68	127	286	195	149	191
Irregular return (26-37)	36	75	69	55	41	86
Regular return-2ª (38-46)	10	20	9	28	35	18
Delayed returns (>46)	3	5	5	15	70	20
Regular-1ª to regular -2ª	6.80	6,35	31,78	6,96	4,26	10,61
Regular to irregular	2,17	1.96	4.28	4.05	4.49	2.43
Abortions	37	165	101	98	110	134
Nulliparous abortions	16	22	10	8	17	15
Sow abortions	21	143	91	90	93	119

In the farrowing house, in addition to the higher pre-weaning mortality, there is an increase in the number of sows that wean 0 piglets.

Table 4- No. of weanings, 6 periods of 12 months.

	01-apr-10 31-mar-11	01-apr-11 31-mar-12	01-apr-12 31-mar-13	01-apr-13 31-mar-14	01-apr-14 31-mar-15	01-apr-15 31-mar-16
Weaned sows	692	2,656	3,626	3,823	3,960	4,114
(as % of total)	3.7%	14.1%	19.2%	20.3%	21.0%	21.8%
Weaned sows without litter	31	143	202	185	293	362

After an analysis of the data, we visit the farm. There are quite a few litters in the farrowing house, especially from young sows, with low viability, poor looking piglets also showing lack of milk intake.

In addition, piglets are found with haemorrhages and necrosis.

Haemorrhages are also seen in sows.

Vulvar necrosis and vulvitis were also observed.

All these symptoms are compatible with a high mycotoxin presence in feed, in particular zearalenone and vomitoxin, and they explain the worsening of reproductive performance observed in recent months. The intensity of the symptoms will depend on exposure time and toxin concentration in the feed, although those clinical pictures offer no doubt about the source of the problem.

Conclusions and recommendations

The two problems described have different causes and, therefore, different solutions:

1. Low prolificacy. Action must be taken in two areas:
   • If possible, increasing the percentage of genetics A sows and reducing genetics B females. The difference between them is remarkable: approximately one extra piglet for genetics A.
   • Increasing lactation length. A large increase is not necessary, since that would also affect other productive parameters of the farm. An increase of 2-3 days, which could translate into an increase of between 0.5 and 1 extra piglets per litter, would be enough. The supply of 30 extra farrowing pens would allow an extension of those 2.5 to 3 lactation days
2. Mycotoxins The objective should be the reduction or elimination of mycotoxin levels in feed processing. For this, the use of raw materials with a high-suspected risk should be avoided and an effective mycotoxin binder should be routinely included. Apparently, a binder is already being incorporated, so it is recommended either to review its dosage or to rotate the product. It is also recommended to implement a routine quality control plan that includes a routine mycotoxin analysis of the raw materials used.

Finally, it should be noted that this case shows the convenience of combining farm visits with a thorough data analysis, for better detection of the causes of a specific problem and its possible solutions.