Estimated reading time: 7 minutes
The value of testing for feed efficiency, how to build a ruminant from birth to slaughter, the wonder of conception and re-conception, and possible alternative feed sources in difficult times. These were the topics discussed during the morning sessions on the second day of the LRF Stockman School held at Aldam in the Free State. The sessions were sponsored by Vytelle and Vleissentraal.
‘Building’ a ruminant
First up was Erin Graham, technical manager at Molatek, who spoke about building a ruminant. Rearing a ruminant from birth to slaughter, she said, is a lot like building a house. It demands planning, precision, and the right ‘materials’ at every stage. From the moment of conception to the final finishing touches before market, each phase contributes to the overall integrity of the ‘structure’.
This happens in steps, and skipping one or using poor-quality inputs early on can lead to costly catastrophes later. To ‘build’ a ruminant brick by brick, there are several critical stages of feeding and development, and foundational elements that determine its success.
Every builder needs a blueprint. In livestock production, these blueprints are the non-negotiables and include genetics, nutrition, health management, and environment. They shape the potential of the animal long before feed enters the picture.
The construction phases
Phase 1 entails laying the foundation which begins before birth with the dam’s nutrition and care during pregnancy. Colostrum intake in the first hours of life is like pouring concrete – it sets the immune system and establishes early health.
Phase 2 entails framing the structure – in the early weeks, the calf or lamb transitions from a monogastric-like milk stomach to a fully functional rumen. A high-quality diet acts as scaffolding, supporting microbial colonisation and rumen papillae development. Without proper framing, the digestive system remains inefficient.
Phase 3 is the roofing and insulation stage which entails weaning, while protecting the young animal from external stressors. Phase 4 is the interior design stage or the finishing phase, whether in a feedlot or on veld. Energy-dense feed adds polish and market value, while carcass quality becomes the curb appeal. Finishing is where the animal’s potential is realised.
But there’s the twist, she stressed: A fancy finish cannot fix a cracked foundation. A calf or lamb that began life with weak genetics, poor maternal nutrition, or inadequate colostrum will always carry those limitations. That is why successful producers invest in the early stages, knowing it pays dividends at slaughter.
The value of testing for feed efficiency
Dr Nina Casagrande, global partner manager at the precision livestock company, Vytelle, explained the value of testing for feed efficiency. The global beef industry, she said, faces a triple challenge. Not only is protein demand increasing, but the demand for environmental sustainability is also rising.
The third challenge is profitability. The answer lies largely in genetic progress, she said. This means more milk and meat with less resources. The key performance indicators are feed conversion ratio, residual feed intake (or net feed intake), average daily gain, dry matter intake and maintenance energy.
The difference between feed conversion ratio (FCR) and net feed intake (NFI) is important, she explained. FCR is a ratio of intake to bodyweight gain, often also calculated on a group rather than on an individual animal basis. Animals with low FCRs consume less feed per pound of bodyweight gain, while animals with higher FCRs consume more feed per unit of weight gain.
The greatest limitation of FCR is that it represents a gross measure of feed intake, meaning it does not distinguish between growth and maintenance requirements. It is therefore difficult to select for low maintenance requirements because it is related to both growth rate and body size. Selecting for improved FCR and increased growth is likely to result in increased maintenance requirements and increased animal body size.
NFI, on the other hand, separates feed intake into two different components: feed intake for a given level of production, and the residual portion of feed. NFI is defined as the difference between an animal’s actual feed intake and its expected feed requirements for maintenance and growth. Actual feed intake vs expected feed intake is then expressed in an NFI figure, either positive or negative. Negative is good, for it implies that for the same level of growth and production, one animal ate less than another.
“In terms of long-term feasibility and the ability for the producer to stay on the farm, being more efficient is very important, especially when we think about emerging farmers with less resources. Whether it’s an intensive or extensive system does not really matter – we all need efficient animals.
NFI is considered to be independent of production, growth and body size, making it an ideal trait to select for feed efficiency as it does not compromise other economically viable traits. It has a moderate heritability of between 30 and 35%.
There are several operational benefits, such as lower feed costs without sacrificing performance, the ability to run more cows on the same area, and being able to produce cattle that convert feed more efficiently and produce less methane. Furthermore, she stressed, selecting for efficiency is a principled decision, grounded in the belief of better resource use.
The miracle of life
Conception and re-conception as the pivot of livestock farming – that was the topic addressed by Dr Douglas Bruce, a veterinarian with the Bargrove Veterinary Group in Zimbabwe. Livestock farming, he said, is all about the miracle of conception. This miracle is a microscopic event.
He went on to describe the role of the various parts of the reproductive system, starting with the ovaries that are filled with oocytes and driven by the hormones progesterone and oestrogen. Body condition score, he emphasised, critically affects the entire sequence of events right through the process, from conception to birth. This means that nutrition management is key.
He used the example of a specific cow that had an intercalving period (ICP) of 306 days, or ten months. That is six calves in five years or 12 in ten years and if she calved first at two years, that is 12 calves in 12 years. Put differently, for every five cows with an ICP of ten months you get one extra calf, or two for every ten cows. This translates into a calving percentage of 120%.
The ideal cow, he stressed, is the type of animal that calves every year and is pregnant again at weaning. Identify her and select for her!
Watch this video in which Dr Bruce demonstrated how the cow’s reproductive organs work.
Alternative feed sources for difficult times
Prof Cletos Mapiye, associate professor in Meat Science at Stellenbosch University, ended the session by looking at possible alternative feed sources in difficult times.
He discussed 15 different classes of alternative feed sources, together with their key climate-smart attributes, nutritional attributes, and key phytochemicals as well as their contribution to the environment, cattle, and their effect on meat quality. Finally, he looked at their key anti-nutritional factors (ANFs) and how these effects could be minimised.
The 15 classes were improved forage grasses, such as Napier grass and signal grass; alternative cereal grains and byproducts such as sorghum, finger millet and amaranth; root and tuber crops and their byproducts such as cassava, sweet potato, yams and potatoes; alternative grain and herbaceous legumes such as lablab, lespedeza and silverleaf; alternative oilseeds and byproducts such as oilseed meal/cake from camelina and chia; trees, shrubs and herbs such as acacia, Vachellia, rosemary and oregano; woody byproducts such as bark meal, sawdust and shavings; fibre crop byproducts for oils and oilseeds such as hempseeds, flaxseed and cottonseeds; fruit byproducts such as pomace, peels and skins; halophytes such as saltbush and sea spinach; xerophytes and byproducts such spineless cactus and aloe vera waste; aquatic plants and their byproducts such as seaweeds; aquatic animal byproducts; terrestrial animal byproducts; insects and former food products.
A future research strategy for alternative feeds, he concluded, should be to assess nutritional composition, phytochemical profile and bioactivity of alternative feeds and ascertain mechanisms of action, determine safety limits, standardize and optimise application conditions.
In conclusion, a holistic evaluation is necessary of the effects of alternative feeds on GHG emissions, safety, animal health and welfare, meat production and quality and economic viability. – Izak Hofmeyr, Plaas Media
