Importance of feed intake in commercial layer systems

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 By Herman Rossouw, technical advisor,  AFGRI Animal Feeds

The feed component of the average poultry production system makes up 70% of all expenses. Given the sharp increase in feed prices these past three years, there is renewed focus on the consumption and effectiveness of rations. In March this year, the average layer meal was 80% more expensive than in the corresponding month in 2020. In comparison, the price paid to producers for a dozen eggs rose by only around 30% in the same period. But what does optimal daily feed intake per hen in commercial egg production systems look like? The answer is somewhat complex.

Factors affecting feed intake
Excessive feed intake leads to financial losses because it adds to the feed bill and leads to health problems such as fatty liver; if the hen ingests too little feed, she will not be ingesting the nutrients she needs for optimal production and health.

A multitude of factors affect feed intake. These include temperature, humidity, water intake, housing density (competition for feeding space), diseases, stress, feed particle size, energy density of the feed, age and weight of the hen, as well as breed.

Each feed company has its own range of layer rations that differ in terms of nutrient density and energy composition – in other words, the optimal daily feed intake per hen will vary. Communication between the feed company and the producer regarding the theoretical and actual intake of a ration is therefore key.

Temperature and particle size
Hens tend to ingest less feed in the warm summer months, making it difficult to keep the actual intake in line with the theoretical intake. A more nutrient-dense feed will help to support hen production and bodyweight maintenance in summer. In this regard, management practices such as midnight feeding may assist in stimulating intake. Moreover, there are a number of supplements on the market that may help to alleviate heat stress.

Feed particle size – and more specifically changes in particle size – can quickly suppress or overstimulate hens’ feed intake. Not only will hens consume less feed if it is too fine, but such feed may also create dust in houses and lead to respiratory infections in hens and workers. Coarse particles, on the other hand, will stimulate feed ingestion, leading to selective feeding habits with hens selecting to eat the coarse particles (usually maize) first, leaving the finer particles (vitamins, minerals, enzymes and the like) behind.

With the latter in mind, it is important in especially older production systems, which still make use of manual feeding, that the hens clean out the feeders before new feed is added. To accomplish this, more daily feedings can be allowed rather than filling up the feeders in the mornings only.

Feed according to age
Although hens’ ration intake can be controlled to some extent, their physiology must be kept in mind. Young point-of-lay hens will not consume the same amount of feed than 60-week-old hens. Hence, rations and management practices need to be adjusted accordingly.

AFGRI’s Optilay Peak ration is specifically formulated for young point-of-lay hens that are physiologically unable to achieve intakes of 110 to 120g/hen/day. Once hens reach a physiological age at which they can comfortably ingest 110g/hen/day, the ration can be switched to Optilay 20.

‘To measure is to know’ is one of my favourite sayings and is very apt when it comes to feed levels and ultimately feed intakes. Daily feed intake per hen per day is the best way to identify problems early on, either with regard to the feed, hens or management practices.

Feeding the transition cow

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By SP Els, AFGRI Animal Feeds

Sound nutrition and management practices during the transition period will have a positive financial impact on dairy businesses.

Most farmers have specific, quantifiable goals regarding milk production, milk solids, feed and labour costs, and profitability in terms of profit per hectare or per cow. However, it seems that the opposite is true for reproduction and cow comfort.

Low dry matter intake (DMI), with subsequent negative energy balance (NEB) and metabolic disorders, as well as management and environmental factors occurring during the transition period, are responsible for reproductive failure and profit loss, and not high milk production as is commonly believed.

 

Pre- and postpartum feeding

 The transition period generally extends from three weeks before calving until three weeks after calving. During this phase, the cow undergoes dramatic physiological, immunological, metabolic and nutritional changes.

Formulating diets with a negative dietary cation-anion difference (DCAD) in the prepartum period in a bid to reduce subclinical and clinical hypocalcaemia and its associated diseases, is but one aspect of the nutritional strategy aimed at supporting metabolic adaption during the transition period.

Demand for amino acids, glucose and fatty acids at day 250 of gestation, increases approximately fivefold at day four postpartum for some of these nutrients. Furthermore, changes in the demand and supply of these nutrients, minerals and trace minerals postpartum directly impact immune function.

The question remains whether the feeding strategy is amended pre- and postpartum to help the liver function optimally and adapt the rumen, which is going through morphological, functional and microbiota changes, to achieve the   following:

  • Higher DMI.
  • Shortened duration of NEB.
  • Higher glucose concentrations.
  • Increased levels of circulating IGF-1.
  • Lower non-esterified fatty acid (NEFA) concentrations.

Higher levels of NEFA in the blood is associated with lower reproduction and reduced oocyte quality and may lower the survival rate of the embryo after fertilisation. If the cow produced a calf from an inferior embryo, the gene expression of the calf may be negatively impacted, a process known as epigenetics. Epigenetics is a change in the genes’ core functionality and is impacted by something other than DNA; in this case, ‘poor’ nutrition pre- and postpartum.

 

Carbohydrates, amino acids, minerals 

Further nutritional strategies to consider are to feed a mix of carbohydrates and to finetune the amount of carbohydrates based on the dry, fresh and/or early lactation diets, as well as the total fermentable carbohydrates fed. The digestibility of starch as well as neutral detergent fibre (NDF) must also be measured.

The fibre in diets affects intake and rumen function. The amount of physically effective NDF (peNDF) needed in the fresh diet depends on intake, total starch and rumen degradable starch, forage digestibility and particle size. In addition, supplementing amino acids (the building blocks of enzymes and hormones), which is important in several biological functions during the transition period, has been shown to:

  • Reduce oxidative stress.
  • Increase DMI.
  • Affect embryonic gene expression.
  • Improve immune-metabolic status.

One should be aware of contradictory statements regarding ‘fats’ in transition diets and that only specific fatty acids may have positive effects, for instance decreasing the NEFAs in the liver. Special attention must be given to improving trace mineral availability that will positively impact immune function, and ultimately reproductive performance.

 

Improving feeding behaviour

Feeding behaviour associated with calving, stocking density, grouping and pen movement, may have a negative impact on rumen health. Key factors to remember when wanting to improve feeding behaviour in fresh cows, are:

  • Reduction of heat stress.
  • Maximising opportunities for cows to eat during the day.
  • Keeping fresh cows separate.
  • Avoiding overcrowding in fresh cow pens with a stocking density below or at 85%.

Remember, all dairy cows may experience low DMI, NEB and metabolic disorders to some extent. How these factors are minimised during the transition period through nutrition and sound management, as well as how environmental factors are managed, will positively affect profits.