A recent webinar with Dr. Robert Van Saun, professor and Extension veterinarian with Penn State, dove into the impact of colostrum on the lamb’s ability to not only survive but to thrive long-term.

He began by referencing a study on sheep death loss from USDA. Upward trends were noted in financial loss and in herd inventory percentage loss. A third data set evaluated neonatal mortality. While there are occasional spikes and low points, “when you look at the averages across the board, it appears that we haven’t made a lot of meaningful improvements in neonatal lamb mortality over the last 40 years,” Van Saun said.

He quoted Coach John Wooden: “Failing to prepare is preparing to fail.” Farmers have to set up their dams for success in the lambing process – and a lot of that begins and ends with proper nutritional inputs. Improper feeding, especially late in gestation, can lead to metabolic disease, poor colostrum supply, poor milk yield (and possibly lamb growth), high postnatal losses and more.

Colostrum is the first milk secretion of the mammary gland prior to the time of lambing. Many antibodies, vitamins and other necessary compounds are unable to cross through the placental barrier – particularly later in gestation. Colostrum administers immunoglobulin (IgG, or maternal antibodies) to lambs. Lambs are intrinsically born with no natural immunity; their immune systems are kick-started when they are exposed to various environmental factors or pathogens outside of the birth canal (or a dose of maternal white blood cells, which they will also receive via colostrum and which help facilitate immunity). The IgG bodies provide a much-needed barrier to disease.

Though it’s not a direct comparison, Van Saun shared a study of IgG concentrations in dairy and beef calves as an example. The higher the concentrations of passive IgG transfer available to the calf, their risk of disease (diarrhea and respiratory infections especially) dropped exponentially. However, observing a tight feeding window is key: milk production begins at delivery and will dilute any remaining colostrum levels in the mammary gland. The concentrations of protective IgG levels drop precipitously with each milking.

Colostrum provides energy and fat to support the lamb’s metabolism and supports healthy body temperature. Although some small amounts of vitamins and minerals can transfer during pregnancy, they don’t cross over in “appreciable amounts,” according to Van Saun. It’s important to supplement the ewe with fat soluble vitamins A, D and E as well as various crucial minerals (sodium, calcium, selenium, etc.) throughout the pregnancy. These compounds will then be present in the colostrum and will carry over to lambs.

These minerals can contribute to skeletal growth and immunological effects for the lamb. Colostrum can contribute to various growth factors, stimulating intestinal growth and facilitating proper gut health.

What makes good colostrum, Van Saun said, in addition to proper mineral and vitamin supplementation for the ewe during gestation, is feeding a properly balanced diet. Energy and protein requirements should be factored in based on what she might be carrying (accounting for singles, twins, etc.). Over- or underfeeding can result in deficits to the colostrum, reduced birth weights and other issues. Vaccination of the ewe prior to lambing is also helpful. Vaccination can stimulate the production of protective antibodies which can enter the colostrum.

How do we evaluate the IgG and other levels of the colostrum? The data are still evolving – while there are dependable data for goats and calves, producers are lacking in an equivalent for sheep. Still, there are tools on the market to help the farmer evaluate. A colostrometer utilizes specific gravity and displacement to show results; however, it is limited by the need for a large sample – often not accessible with small ruminants.

An optical and a digital readout Brix refractometer are available, with the digital model being one of the best available options for sheep. A 2023 Penn State Extension article by Jud Heinrichs and Coleen M. Jones noted, “The scale in a Brix refractometer is designed to measure the amount of sucrose in a solution, but Brix values can be related to IgG in colostrum.” A small dot from a colostrum sample is placed on the refractometer’s sensor area and then the information is readily accessible on the screen.

Van Saun closed the session by reiterating, “Colostrum management has the potential for improving lamb survival with proper feeding practices.”

He referenced the principles of proper management as his “3 Qs”:

  • Quality – the solution should be more than 80 mg/mL (greater than 34% Brix)
  • Quantity – the lamb should be receiving 50 ml/kg of body weight (which also translates to 1 oz./lb.)
  • Quickly – the first feeding should be within two hours of delivery

The next feedings (3 oz./lb. spread over three or more feedings) should occur within 24 hours of delivery. While raw colostrum from the dam is preferred, substitutions are available. Farmers can use pooled ewe colostrum from the same flock, pooled colostrum from a different flock with the same disease profile, artificial colostrum replacer, etc.

There is a lot of variation in the study and assessment of passive IgG transfer and colostrum components across different breeds, but the current data are a starting point. There is potential for even greater progress and breakthrough with additional research and study.

by Andy Haman