Technological aspects of intensive pig farming and the Danish production system

Modern intensive pig farming is based on maximizing the genetic potential of livestock animals and a high level of automation. The introduction of advanced technologies allows for reducing production costs and increasing competitiveness. To obtain viable young stock with high growth energy and excellent feed conversion, industrial crossbreeding is used at enterprises. The best results are achieved by hybridizing breeds with proven positive combining ability.

Reproductive efficiency depends directly on the technological level of the farm. The use of modern industrial complexes allows for almost doubling key sow productivity indicators compared to traditional farms. Efficiency gains are achieved through the mechanization of processes and the improvement of housing conditions for the animals.

Depending on the strategy adopted at the enterprise, early weaning of piglets from their mothers at the age of 26–45 days is practiced, or traditional weaning at 60 days. After this, weaned piglets are sorted by litter or formed into groups of 20–25 animals of the same age with equal live weight. Rearing young stock can follow a one-, two-, or three-stage scheme.

Moving young stock to the finishing stage is carried out at the age of 3–4 months upon reaching a live weight of 30–40 kg. The animals are placed in groups of 10–15 to 25 head in pens. Feeding is organized using group feeders, ensuring free access to balanced rations.

• Early weaning of piglets — 26–45 days
• Area per weaned piglet — 0.35 m²
• Area per head during finishing — 0.8 m²
• Pig finishing period — 160–180 days
• Target weight at slaughter — 100–110 kg

Technological zones and features of the Danish rearing system

The Danish pork production technology provides for strict zoning of the pig complex facilities. This allows for the optimization of veterinary control, the adjustment of targeted feeding, and the automation of manure removal. The production cycle at the enterprise is divided into four specialized technological zones.

In the first zone, insemination and housing of pregnant sows are carried out. Here, the onset of estrus in sows is monitored, collection and preparation of boar semen are performed, and artificial insemination is conducted. In the second zone, individual crates for restricted sow housing are equipped, bedding for piglets is prepared, and farrowing takes place.

Care for newborn suckling piglets during the suckling period requires special attention from the staff. Timely veterinary and hygienic measures help reduce mortality and stimulate the growth of young stock. The traditional scheme of litter care includes several sequential steps.

1. Standardizing the litter and assisting newborn piglets to the teats of the udder.
2. Processing young stock and performing prophylaxis against enteritis, anemia, and coccidiosis.
3. Tail docking and castration of male piglets.
4. Organizing early top dressing for suckling piglets with specialized feed.

In the third zone, weaning piglet rearing takes place with monitoring of weight, bedding size, and the condition of slatted floors. Technological techniques are also implemented here to prevent cannibalism among young stock. The fourth zone is intended for the final finishing of pigs with automatic distribution of feed mixtures and maintenance of optimal temperature of water in automatic drinkers.

The efficiency of a pig-breeding complex is evaluated by the level of prolificacy, fertility, herd survival rate, and feed costs per centner of weight gain. The most important economic markers remain production costs and production profitability. To timely assess the breeding qualities of animals, regular herd control measures are carried out at the enterprise.

All pig breeds, depending on their productivity direction, are divided into two groups:

1. Group 1 – Large White, Large Black, North Caucasian, Breitovskaya, Belarusian Black-Pied, Kemerovo, Short-Eared White, Livenskaya, Murom, Tsivilsk, Urzhum, Siberian Northern, Belarusian Large White, Estonian Bacon breeds;
2. Group 2 – Early-maturing meat, Landrace, Duroc, Lithuanian White, Tuklinskaya, Yorkshire, Welsh, Belarusian Meat breeds.

Evaluation of pigs is carried out throughout the year, and the performance testing report is compiled annually as of January 1.

Young stock are selected for rearing from the herd having 14 (7/7) or more teats in boars and at least 12 (6/6) normally developed teats in sows from parents with a total score not lower than class 1 requirements.

Young stock are weighed upon reaching a live weight of 90–110 kg, and the following measurements are taken with recalculation to 100 kg:

• body length (from the occipital crest to the tail root);
• feed costs per 1 kg of live weight gain;
• backfat thickness at two points at a distance of 5 cm to the left or right of the dorsal midline: point P1 – above the 6th–7th thoracic vertebrae, point P3 – above the last rib.

Standard requirements for the assessed indicators of young pigs are presented in tables 1, 2, 3.

The elite class includes boars and sows that have received 90 points or more, while the first class includes those with 85–89 points.

Pigs having the following defects are culled from the herd:

• sharp constriction behind the shoulder blade or loin;

Test and main sows are evaluated for their own productivity using data from their assessment at 100 kg live weight – by age at reaching weight, feed costs per 1 kg of live weight gain, backfat thickness above the 6th–7th thoracic vertebrae, body length, and conformation.

Reproductive qualities of test sows are evaluated by their first farrowing, and of main sows – by their first and on average by two or more farrowings according to the following indicators:

• litter weight recalculated to 30 days.

At birth and at weaning at 30 days, piglets are weighed by litter. In case of weaning piglets at the age of 21 to 62 days, the adjusted litter weight at 30 days is determined taking into account correction factors.

Fattening and meat qualities of sows are evaluated on average based on the indicators of all offspring available on the date of assessment:

• age of reaching 100 kg live weight (days);

– backfat thickness (in vivo) above the 6th–7th thoracic vertebrae (mm);

– feed costs per 1 kg of live weight gain (kg);

Standard requirements for the assessed indicators of test and main sows are presented in tables 4, 5, 6.

Table 1 – Scale for the assessment of replacement young stock of the 2nd group of breeds by live weight and body length (minimum requirements)

Live weight, kg Mo. Body length, cm weight, kg length, cm elite 1st cl. elite 1st cl. elite 1st cl. elite 1st cl.

2 10 25 23 – – 26 23 – –

3 10 42 36 – – 42 36 – –

4 10 60 53 – – 58 51 – –

– 72 66 118 114 68 61 – –

5 10 78 71 120 116 74 66 – –

20 85 77 122 118 80 71 – –

– 92 83 124 120 86 76 119 116

6 10 98 89 126 122 92 81 121 119

20 105 95 129 124 99 87 123 120

– 111 101 132 126 105 92 128 122

7 10 117 106 134 128 110 97 130 123

20 124 111 136 130 115 101 132 125

– 129 115 138 132 120 105 135 127

8 10 134 121 140 134 125 109 136 128

20 140 127 143 136 129 113 137 130

– 146 133 146 138 133 117 139 132

9 10 151 139 148 140 137 121 140 134

20 157 143 151 142 141 125 142 136

– 160 147 154 144 144 129 145 137 10 10 163 150 155 146 147 133 147 138

20 167 155 157 147 150 138 148 139

– 170 159 158 149 154 143 149 140 11 10 173 163 159 150 159 147 150 141

20 178 165 160 151 164 152 151 142 12 185 167 161 153 170 157 151 143

Table 2 – Scale for the assessment of replacement young stock upon reaching

Age Feed costs Backfat thickness Breed Body length,

Class reaching, per 1 kg of live above 6–7 thoracic groups cm days weight gain, kg vertebrae, mm

Elite 195 or less 3.7 or less 25 or less 122 or more 1st I 196–205 3.71–3.80 26–30 117–121

Out of class 206 or more 3.81 or more 31 or more 116 or less

Elite 185 or less 3.4 or less 21 or less 123 or more 2nd I 186–195 3.41–3.5 22–24 117–122

Out of class 196 or more 3.51 or more 25 or more 116 or less

Elite 185 or less 3.5 or less 23 or less 124 or more 1st I 186–195 3.51–3.60 24–28 119–123

Out of class 196 or more 3.61 or more 29 or more 118 or less

Elite 175 or less 3.2 or less 20 or less 126 or more 2nd I 176–185 3.21–3.30 21–23 120–125

Out of class 186 or more 3.31 or more 24 or more 119 or less

Table 3 – Scale for the assessment of the conformation of replacement young stock

General appearance and individual points boars sows General appearance, constitution, breed characteristics,

20 20 skin, bristles Head, neck 5 5 Shoulders, withers, chest 10 10 Back, loin, sides 15 15 Sacrum, hams 20 20 Front legs 7 7 Hind legs 8 8 Teats, sow udder 5 15 Boar reproductive organs 10 – Total: 100 100

Table 4 – Correction factors for recalculating litter live weight days days days

21 1.47 35 0.86 49 0.54

22 1.40 36 0.82 50 0.52

23 1.32 37 0.79 51 0.51

24 1.26 38 0.76 52 0.50

25 1.20 39 0.73 53 0.48

26 1.15 40 0.70 54 0.47

27 1.11 41 0.68 55 0.46

28 1.07 42 0.66 56 0.45

29 1.04 43 0.64 57 0.44

30 1.00 44 0.62 58 0.42

31 0.97 45 0.60 59 0.41

32 0.94 46 0.58 60 0.40

33 0.91 47 0.57 61 0.39

34 0.88 48 0.55 62 0.38

The adjusted litter weight at 30 days is determined by multiplying the litter weight at actual weaning between 21 and 62 days by the corresponding factor.

Assessment of productivity of test and main boars

Test and main boars are evaluated for their own productivity using data from their assessment at 100 kg live weight – by age at reaching weight, feed costs per 1 kg of live weight gain, backfat thickness above the 6th–7th thoracic vertebrae, body length, and conformation.

Reproductive qualities of test and main boars are evaluated based on the average prolificacy of 5 or more sows inseminated by them.

Fattening and meat qualities of main boars are evaluated on average based on the indicators of all offspring available on the date of assessment:

– age of reaching 100 kg live weight (days);

– backfat thickness (in vivo) above the 6th–7th thoracic vertebrae (mm);

– feed costs per 1 kg of live weight gain (kg);

Table 5 – Scale for the assessment of test and main sows heads at 30 days**, heads at 30 days, kg***

Elite 11.0 or more 9.9 or more 70 or more

I class 9.2–10.9 8.1–9.8 64–69

Out of class 9.1 or less 8 or less 63 or less

Elite 9.0 or more 8.6 or more 65 or more

I class 8.2–8.9 7.2–8.5 62–64

Out of class 8.1 or less 7.1 or less 61 or less

* – taking into account all farrowings in sows and at least 5 farrowings in boars

*** – including those recalculated at actual weaning

Table 6 – Scale for evaluating performance-tested and primary boars and sows based on the fattening and meat qualities of their offspring per 1 kg of gain. Breed group Classes over 6–7 vertebrae

Elite 190 or less 3.7 or less 24 or less

1st Class I 191–200 3.71–3.80 25–28

Out of class 201 or more 3.81 or more 29 or more

Elite 180 or less 3.6 or less 20 or less

2nd Class I 181–190 3.61–3.70 21–24

Out of class 191 or more 3.71 or more 25 or more

Actual productivity indicators for replacement young stock are recalculated to a live weight of 100 kg as follows:

The age at which 100 kg weight is reached is calculated using the formula:

where X is the age at which 100 kg weight is reached (days);

B is the actual age on the day of the last weighing (days);

M is the actual live weight of the livestock animal on the day of the last weighing (kg);

P is the average daily live weight gain during rearing (kg).

Backfat thickness is calculated taking into account a correction of 0.3 mm per 1 kg of live weight, reducing or increasing the actual backfat thickness depending on the increase or decrease in live weight from the standard value.

Body length is calculated taking into account a correction of 0.2 cm per each kilogram of live weight, reducing or increasing the actual length depending on the increase or decrease in live weight from the standard value of 100 kg.

The obtained indicators are rounded: age at reaching 100 kg live weight – to 1 day; average daily gain – to 1 g; backfat thickness – to 1 mm; body length – to 1 cm.

Based on the indicators for evaluating development and conformation of replacement young stock, and the productivity of performance-tested and primary boars, an average score value is established, which is used to determine the total class of pigs: elite and I (first) class. Animals below the first class are subject to culling.

Table 7 – Scale for determining the total class by average score

Elite 4 3.6–4.0

Class I 3 2.6–3.5

The class of replacement gilts and young boars based on fattening and meat qualities is determined taking into account the results of their evaluation for individual productivity, age at reaching 100 kg live weight, feed cost per 1 kg of live weight gain, backfat thickness over the 6–7 thoracic vertebrae, body length, and conformation.

The total class of replacement young stock is determined by summing the scores for the recorded traits and dividing the resulting total by the number of the specified indicators (for development and conformation, fattening, and meat qualities).

Determination of the total class of performance-tested and primary sows

For fattening and meat qualities, it is determined taking into account the results of their evaluation for individual productivity – age at reaching 100 kg live weight, feed cost per 1 kg of live weight gain, backfat thickness over the 6–7 thoracic vertebrae, body length, and conformation.

The class for reproductive qualities is assigned based on indicators – prolificacy, number of piglets, and litter weight calculated at 30 days. Scores for the specified traits are summed up, and an average score for reproductive qualities is established.

The class of primary sows for fattening and meat qualities is determined based on the performance indicators of all offspring evaluated in vivo for their individual productivity:

– age at reaching 100 kg live weight;

– feed cost per 1 kg of live weight gain;

– backfat thickness over the 6–7 thoracic vertebrae.

The total class of performance-tested and primary sows is determined by summing the scores for the recorded traits and dividing the resulting total by the number of the specified indicators (for development and conformation, reproductive, fattening, and meat qualities).

Determination of the total class of performance-tested and primary boars

For fattening and meat qualities, it is determined taking into account the results of their evaluation for individual productivity – age at reaching 100 kg live weight, feed cost per 1 kg of live weight gain, backfat thickness over the 6–7 thoracic vertebrae, body length, and conformation.

The boar's class for reproductive qualities is assigned based on the prolificacy of 5 or more sows they have inseminated.

The class of primary boars for fattening and meat qualities is determined based on the performance indicators of all offspring evaluated in vivo for their individual productivity:

– age at reaching 100 kg live weight;

– feed cost per 1 kg of live weight gain;

– backfat thickness over the 6–7 thoracic vertebrae.

The total class of performance-tested and primary boars is determined by summing the scores for the recorded traits and dividing the resulting total by the number of the specified indicators (for development and conformation, reproductive, fattening, and meat qualities).

Task 4. Master the methodology of control fattening of pigs.

Methodology. For a comprehensive characterization of the breeding and productive qualities of pigs, along with the evaluation of individual productivity, they are evaluated by the quality of their offspring using the control fattening method.

Control fattening of pigs is carried out at control fattening stations. For evaluation, sows are selected from among the performance-tested ones, designated for selection into the primary breeding herd based on farrowing results.

At least three sows are assigned to each boar being tested. From the litter of each assigned sow, 4 gilts and 3 barrows (castrated males) are selected, or 3 gilts and 2 barrows, or 2 weaners (gilts or barrows) from six litters with a live weight of at least 18 kg (class 1 standard).

Young animals intended for performance testing are castrated (the males) at 20–30 days of age.

Before being sent to the performance testing station, the animals are placed in a 20-day preventive quarantine, during which the piglets are vaccinated against erysipelas no later than 14 days before shipment. Vaccinations against "Swine Fever" and "Aujeszky's Disease" are carried out as indicated. Preventive veterinary treatments are not permitted during the recording period. In case of illness, animals are removed from performance testing.

Feeding is carried out using special compound feed. During the feeding period, 1.5 l of skimmed milk is given per head. Feeding is performed twice a day, ad libitum, to a "dry trough" state.

Performance testing is divided into 2 periods: 1 – preparatory and 2 – recording. The recording period begins when the animals reach a live weight of 30 kg and ends when they reach an average live weight of 100 kg at an age no later than 211 days.

Task 5. According to the variant in Appendix 1 to Topic 3, evaluate the individual productivity of the sows.

Methodology. Sow productivity is evaluated based on individual productivity (age at reaching 100 kg live weight, backfat thickness, body length, conformation, and reproductive qualities (fecundity, number of piglets, and litter weight at 30 days of age); scores and classes are assigned based on these indicators. The data are entered into Table 8.

Table 8 – Evaluation of productive and reproductive qualities of sows

Task 6. According to the variant in Appendix 2 to Topic 3, evaluate sows and boars based on the fattening and meat qualities of their offspring.

Methodology. The primary evaluation of boars is considered to be the evaluation of the fattening and meat qualities of their offspring via the performance testing method, taking into account:

– age at reaching 100 kg live weight (days)

– feed costs per 1 kg of live weight gain, kg

– backfat thickness above the 6th–7th thoracic vertebrae, mm.

Table 9 – Evaluation of sows and boars by fattening and meat qualities

Productive and reproductive qualities of evaluated sows

Length 1 2 3 4 5 6 7 8 9 10

1 11 10 70.5 124 193 26

Large White – 1 1916 2 12 11 69 122 197 24

3 13 13 78 119 200 25 1, 1 12 11 77 119 196 26 10, North Caucasian – 1 Soya 2410 2 11 11 78 120 199 27 20 3 11 10 71 121 212 28

Early-maturing 1 9 8 62 123 187 19

Slava 7210 2 10 9 70 122 180 18

3 9 9 65 124 188 20

1 12 11 79 116 200 24

Large Black – 1 2 13 12 89 118 203 26

2112 3 12 12 85 120 196 27 2, 1 11 11 79 121 211 25 11, Breitovo – 1 Linda 090 2 10 10 73 119 200 26 21 3 12 11 77 115 190 27

1 9 9 68 125 180 19