Fundamentals of ontogeny and methodology for assessing the growth of livestock animals

Ontogenesis is a continuous process of qualitative and quantitative changes occurring in the organism of a livestock animal from conception to death (throughout its life).

Each species of livestock animals is characterized by: periodization of prenatal and postnatal development, patterns of growth and development processes of individual body parts, organs, tissues, and indicators of their economic and biological characteristics.

Task 1. Note and study the name and duration of the main periods of prenatal and postnatal ontogenesis of livestock animals. Enter the data into Table 1. Table 1 – Name and duration of ontogenesis periods for cattle Name: Pregnancy and calving Prenatal ontogenesis periods, days: total incl.: embryonic pre-fetal fetal Postnatal ontogenesis periods: neonatal, days milk, months sexual maturity, months economic maturity, months old age, years

Task 2. Using the data in the table below, determine the increase in measurements and live weight of Holstein cattle from birth to 5 years of age and their growth in percentage during prenatal and postnatal ontogenesis. Table 2 – Measurements (cm) and live weight (kg) of Holstein cattle in prenatal and postnatal ontogenesis

76.2–81.6 137 at withers Height

80.9–86.4 143 at sacrum Chest depth 27.2–29.6 72.8

Chest width 15.5–16.2 45.5

15.8–16.5 56.4 at hook bones

Metacarpus girth 10.2–11.1 19.3

Live weight 33.5–38.5 565

Task 3. Using the data in the table below, establish the features of weight growth of internal organs of Holstein cattle in prenatal and postnatal ontogenesis. Table 3 – Weight of internal organs of Holstein cattle in prenatal and postnatal ontogenesis (g)

5 years birth to 5 years prenatal ontogenesis Heart 218 2500 Lungs 343 3600 Liver 632 7800 Spleen 58 908 Kidneys 95 1443 Rumen 88 8700

Continuation of Table 3 Reticulum 21 1800 Omasum 42 4700

Task 4. Master the methodology for studying animal growth.

Methodology. Indicators of animal growth are calculated using the following formulas:

a) Absolute gain (mass, dimensions, volume) for the period:

where A – absolute gain; kg (cm, cm3)

Wk – value of the trait at the end of the period; kg (cm, cm3)

Wn – value of the trait at the beginning of the period; kg (cm, cm3) where ADG – absolute average daily gain; g

A – absolute gain for the period; kg

tk – age of the animal at the end of the period; days

tn – age of the animal at the beginning of the period; days

T – interval between the initial and final period; days c) Relative growth rate (for a certain period of time) in % of the growing mass:

Wk – indicator at the end of the period; kg

Wn – indicator at the beginning of the period; kg

Task 5. Using the data from Appendix No. 1 to Topic 2, determine the absolute and relative gain in live weight of livestock animals of various species. Enter the results in the table below.

Table 4 – Absolute and relative gains of animals of various species from birth to the period of economic maturity

Species Age of animals in months at birth Gain

Indicators at birth 1 2 3 6 9 12 18 24 36

Live weight, (kg) at age, months No. of animal at birth 1 2 3 6 9 12 18 24 36

Horse 45 75 102 135 184 221 272 347 368 402 cattle 34 55 76 98 171 191 272 360 – – 1, 10, 20

Sheep 3 7 12 19 24 29 36 45 – –

Pig 1.4 6 15 25 67 120 – – – –

Goat 2.8 7.0 13.2 17.7 25 26 27 33 40 45

Rabbit 0.04 0.36 1.2 2.3 2.6 3.0 3.3 3.5 3.7 4

Horse 42 67 38 127 200 267 344 390 422 450 cattle 28 49 66 88 156 190 269 355 – – 2, 11,

Sheep 4 8 13 20 28 33 38 42 – –

Pig 1.3 6 14 25 69 118 – – – –

Goat 2.9 7.4 13.5 18.5 26 27 28 34 41 47

Rabbit 0.05 0.39 1.3 2.4 2.7 3.1 3.4 3.6 3.8 4.5

Horse 48 83 103 134 204 279 351 397 426 464 cattle 32 53 72 94 165 192 273 371 – – 3, 12,

Sheep 5 9 14 21 28 33 39 43 – –

Pig 1.2 5.5 15 23 71 118 – – – –

Goat 3.0 8.4 14.2 18.9 27 28 30 35 43 48

Rabbit 0.07 0.4 1.4 2.5 2.8 3.2 3.5 3.8 4.0 5.0

Horse 46 71 101 121 207 282 354 399 429 460 cattle 35 53 73 95 167 198 226 384 – – 4, 13,

Sheep 3 8 13 20 28 32 37 44 – –

Pig 1.6 8.0 18 31 75 122 – – – –

Goat 3.0 8.9 14.2 19.2 29 31 32 39 48 52

Rabbit 0.08 0.72 1.5 2.7 2.8 3.2 3.5 3.8 4.0 5

Horse 43 68 100 138 204 275 348 393 432 464 cattle 31 51 72 97 168 200 270 370 – – 5, 14,

Sheep 3.5 7.5 12 20 25 30 36 46 – –

Pig 1.2 6.0 16 26 67 116 – – – –

Goat 2.8 7.5 14.2 17.9 25 26 27 33 40 45

Rabbit 0.04 0.45 1.4 2.6 2.7 3.2 3.4 3.7 4 5

Horse 49 73 103 139 230 309 359 428 485 550 6, 15, Cattle

25 23 39 62 83 156 203 268 358 – –

Continuation of Appendix 1 to Topic 1

Sheep 4.5 8.5 14 19 26 31 36 48 – –

Pig 1.3 6.0 14 23 60 117 – – – –

Goat 3.0 8.5 14.9 20.1 28 31 32 38 49 52

Rabbit 0.07 0.57 1.4 2.6 2.7 3.2 3.5 3.7 4 5

47 71 100 136 236 306 356 426 486 546

37 56 74 95 165 200 280 392 – – 7, 16, cattle

Sheep 3 8 12 20 24 33 35 44 – –

Pig 1.1 6.0 16 27 66 110 – – – –

Goat 3.1 9.5 15.8 22.4 29 31 32 39 50 54

Rabbit 0.08 0.7 1.4 2.6 2.8 3.2 3.5 3.8 4.0 5

50 74 104 140 260 310 360 430 490 550

28 45 65 86 156 197 280 380 – – 8, 17, cattle

Sheep 3.7 7.7 14 18 23 32 35 49 – –

Pig 1.1 6.0 16 26 68 115 – – – –

Goat 2.9 8.7 14.6 21.5 27 30 31 38 48 54

Rabbit 0.05 0.65 1.3 2.5 2.7 3.0 3.3 3.5 3.9 4

40 64 94 130 230 300 350 420 480 540

36 56 75 96 170 189 288 440 – – 9, 18, cattle

Sheep 4 9 16 23 31 36 41 44 – –

Pig 1.4 9.0 17 30 72 120 – – – –

Goat 2.9 8.7 14.4 22.0 28 30 31 37 48 50

Rabbit 0.06 0.6 1.3 2.5 2.7 3.0 3.3 3.6 4.0 5