<%@LANGUAGE="JavaScript1.3"%> Swine Production Management - Records - What is the Farrowing Rate?
 

         What is the Farrowing Rate?

 

Dr. John Carr

When visiting my farms a number often requested is the farrowing rate. But why? What does this number actually mean and why is it important?

The farrowing rate is defined as:

 

Number of sows/gilts from that service group that farrow
                -----------------------------------------------------------      x 100%
Number of sows/gilts served

 

So, therefore, if we serve 100 sows and 87 of these animals farrow, we have a farrowing rate of 87%.

Why is the farrowing rate important?

It is only important as it gives us a guide to how many sows are required to be served in this batch.
There are two critical points to this:
  1. It is only a guide.
  2. It is only a current average - if you have a 85% farrowing rate half the time the actual farrowing rate was less the 85%.

The number of sows to serve is determined by the space availability and pig flow. We need to move away from going after pigs/sow/year concept towards an output based/cost realization method of filling the farm. I strongly believe we need to move towards output kg targets rather than biology targets. I would encourage the MLC to recalculate their awards on output efficiency. Thus a 10 sows a week to farrow farm (equivalent to to-days 240/250 sow unit) is likely to require to serve 12 or 13 sows a week. Why?


Table 1

10 sows a week to farrow, breeding requirements

Served number per batch Equivalent farrowing rate
10 100
11 91
12 83
13 76
14 72
It is ludicrous to aim for 91% and above farrowing rate as this is unlikely to occur consistently, therefore, only serving 10 or 11 a week is insane. Serving 12 is most likely to achieve the required 10 to farrow and in the summer time, if fertility is a bit of a problem, serve 13. It is imperative to maintain output rather than computer optimism.

Take an example of two farms. (A) has a farrowing rate of 90% and the other (B) has a farrowing rate of 84% Who is the better farmer?

Instinctively we would suggest farmer A but in fact they are both brothers working on the 240 sow, 10 sows a week to farrow farm used as an example. The farrowing rate they quote depends on how they read their computer records. The records are insensitive between 91 and 83%, it can pick any number determined by previous service history.

Examining this principle further it is surprising that for:

Current farm description

100 sows

200 sows

300 sows

400 sows

500 sows

Suggested farm description

5 per week

10 per week

15 per week

20 per week

25 per week

 

# to serve

FR%

# to serve

FR%

# to serve

FR%

# to serve

FR%

# to serve

FR%

5

100

10

100

15

100

20

100

25

100

6

84

11

91

16

94

21

95

27

93

7

72

12

83

17

89

22

91

29

86

 

 

13

76

18

84

23

87

31

81

 

 

 

 

19

79

24

84

33

76

 

 

 

 

20

75

25

80

35

72

 

 

 

 

 

 

26

77

 

 

 

 

 

 

 

 

27

74

 

 

 

 

 

 

 

 

28

72

 

 

                     

Apparent 'success' and 'failure' is only about one or two sows a week even on big farms. Not that this does allow us to be completely complacent.

The costs associated with not meeting service targets

Failure to meet service targets resulting in 10 pigs not weaned at
30 fixed cost per pig not sold is 300 assuming 1 cost per kg dead weight.

Cost of one sow to 28 days of pregnancy:

 35 days of feed 17.50
  + service costs 10.00
    27.50
   
  • The farrowing rate is 3 ? months historical.
  • The pregnancy detection is 4-6 weeks historical.
  • The non returnable is 3-4 weeks historical.

    You need to use all of these numbers to adjust the required breeding target to ensure that it is more than likely that the required numbers to farrow are achieved.
  1.  Relax about your farrowing rate.
  2.  Serve to your farrowing rate, don't be over optimistic.
  3. Always better to serve one extra than have an empty crate.
  4. If your farrowing rate is erratic, have it examined.
  5. If the computer states the farrowing rate is 87% on the example farm you cannot serve 11.6 sows you have to serve 12.
  6. The farrowing rate is only a guide and a mean number. Half the time you don't achieve it.
  7. You can't make up missed sales the next week and have good even all-in/all-out pig flow.
  8. Predict periods of a reduction of farrowing rate and serve to the expected problem, ie summer infertility problems.
  • Gilts are the driving force behind control of farm success and an even pig flow.
  • A successful gilt pool is the first ring to a successful farm.