The Immunological Benefits of Colostrum

Cows, sheep, and goats have an epitheliochorial type of placenta that does not allow passage of immunoglobulin, hence neonates are born virtually agammaglobulinemic, rendering them susceptible to infection.

Ingestion of colostrum provides maternal immunoglobulins that enterocytes selectively absorb by pinocytosis during the first 24 hours after birth. The ability of the enterocytes to absorb immunoglobulins decreases rapidly soon after birth, resulting in “closure” of the intestines by 24 to 36 hours postpartum. “Closure” of the intestines is thought to be mediated through growth factors, including IGF-1, transforming growth factor-beta 2 (TGF-β2), and growth hormone (GH), all of which are present in colostrum.¹² Ingestion of these growth factors through colostrum causes hyperplasia of intestinal epithelium and a decrease in crypt-to-villus ratio, indicating a shift toward differentiated mature enterocytes.¹² Passively derived immunoglobulins enhance neonatal immunity by functioning as neutralizers and opsonins.

The immune system of the neonate starts to develop from birth, with endogenous IgG reaching functional levels at 3 to 6 weeks of age.¹³ The uptake of maternal leukocytes by the calf also plays a significant role in the development of the neonatal immune system, by enhancing the antigenpresenting capacity of the calf and regulating the immune response.^14-16 Comparison of the immune response of calves fed

■ TABLE 19.1

Composition of Colostrum of Holstein Cows⁶⁹

Item	Mean	SE
Fat (%)	6.70	4.16
Protein (%)	14.92	3.32
Lactose (%)	2.49	0.65
Total solids (%)	27.64	5.84
Ash (%)	0.05	0.01
IgG1 (mg/mL)	34.96	12.23
IgG2 (mg/mL)	6.00	2.82
IgA (mg/mL)	1.66	0.99
IgM (mg/mL)	4.32	2.84
Lactoferrin (mg/mL)	0.82	0.54
Retinol (pg/g)	4.90	1.82
Tocopherol (pg/g)	2.92	3.65
Betacarotene (pg/g)	0.68	0.63
Vitamin E (pg/g of fat)	77.17	33.51
Thiamin (pg/mL)	0.90	0.28
Riboflavin (pg/mL)	4.55	0.31
Niacin (pg/mL)	0.34	1.57
Vitamin B₁₂ (pg/mL)	0.60	0.35
Pyridoxal (pg/mL)	0.15	0.07
Pyridoxamine (pg/mL)	0.21	0.07
Pyridoxine (pg/mL)	0.04	0.07
Calcium (mg/kg)	4716.10	1898.00
Phosphorus (mg/kg)	4452.10	1706.29
Magnesium (mg/kg)	733.24	286.07
Sodium (mg/kg)	1058.93	526.02
Potassium (mg/kg)	2845.89	1159.89
Zinc (mg/kg)	38.10	15.90
Iron (mg/kg)	5.33	3.09
Copper (mg/kg)	0.34	0.14
Sulfur (mg/kg)	2595.67	904.97
Manganese (mg/kg)	0.10	0.11

Ig, Immunoglobulin; SE, standard error.

leukocyte-replete or leukocyte-depleted colostrum indicates that colostral leukocytes enhance humoral immunity and phagocyte function.^17-21 Following experimental Eschericia coli infection, calves fed leukocyte-replete colostrum recovered more quickly and shed fewer bacteria than calves fed leukocyte-depleted colostrum.⁴ Transfer of cellular immunity via colostral leukocytes has also been demonstrated in sheep.²² Colostral leukocytes are destroyed when colostrum is frozen, pasteurized, or fermented.

Ingestion and absorption of colostral immunoglobulins is essential for neonatal ruminants to thrive, and inadequate colostrum consumption increases the risk of disease. The association between failure of passive transfer of immunoglobulins and neonatal infection has been well established in the calf.^23,24 Passive

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Source: Smith Bradford P., Van Metre David C., Pusterla Nicola (eds.). Large Animal Internal Medicine. Part 1. 6th edition. — Elsevier,2020. — 2279 p.. 2020

The Immunological Benefits of Colostrum

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