PRODUCTION CHALLENGES WITH KIKUYU PASTURES

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SP Els, AFGRI Animal Feeds

 

When the grazing platform changes from ryegrass to kikuyu and/or the neutral detergent fibre (NDF) increases and the protein content decreases – historically the first nutrient nutritionist would increase is the crude protein (CP) concentration in the dairy meal. Making decisions based on CP concentrations as well as energy expressed as mega joules metabolizable energy per kg feed (MJME/kg) are based on old ideologies.

 

Formulating rations on CP, soluble protein (SP), rumen degraded protein (RDP), rumen undegraded protein (RUP) and non-protein nitrogen (NPN) which is the amount of nitrogen (N) analysed times 6.25 to give the CP value. This calculation assumes that all proteins in animals and plants have a 16% N content, which is not accurate. Furthermore, the CP value of a feed does not give any indication what the nutritional value of a protein source is, making it invaluable to use as a nutrient. Instead the profile of the amino acids (A/A) of the specific protein source and digestibility will determine the nutritional value. What is further important is that the total NPN and total or individual A/A available in the rumen and lower intestine are met for specific production targets. Frequently advise is given to increase the concentrations of CP in the diet before the profile of the A/A or limiting A/As has been looked at or are known. The profile of the A/A or limiting A/As cannot be overlooked or brushed aside when given advise to increase the concentrations of CP in the diet.

 

Lowering the CP of the cow’s diet offers an opportunity to improve the profitability as well as nitrogen utilization. Some dairy nutrition software has a dynamic rumen model wherein the passage rate of feeds determines the outflow of nutrients from the rumen. This passage rate of feeds is largely determined by feed intake but also adjusted by ration forage content and particle size. Nutrients that are not constant will vary according to feed consumption and ration ingredient such nutrients are metabolizable protein (MP), metabolizable energy (ME), amino acid content of MP, and rumen available protein (peptides and ammonia). Thus, linear programming can no longer be used and dynamic digestion models – nonlinear programming is required.

 

While the ryegrass pasture quality deteriorate and/or kikuyu comes in play consultants will more likely increase the CP content of the dairy meal, without considering that although CP of the pasture decreased, the higher lignin and NDF content and consequently lower NDF digestibility negatively impact dry matter intake (DMI). Generally, cows grazing on 24-hour rye or kikuyu pasture RDP is oversupplied in contrast with the energy especially fermentable carbohydrates which are deficient. On pasture farms energy is still the first limiting nutrient whereas rumen ammonia exceeds 200% of requirements and even on low quality pastures the rumen ammonia requirements are still above 150% – feeding a 10% CP meal. It is important to feed the correct energy and protein “package” instead of CP and ME content.

 

Non-protein nitrogen (NPN) consumed or ammonia derived from the degradation of true protein in the rumen is either used by rumen microbes – the amount used will be determined by the number of and how rapidly they are growing, in other words it will depend on the amount of energy available to the microbes. The rest of the ammonia is either recycled to the rumen via saliva or will be excreted in the urine or as milk urea nitrogen (MUN). The ammonia derived from NPN and from degraded true protein and not used by the microbes will not be of any value. The amount of A/A that is not supplied by the microbes needs to be supplied from bypass feed sources that is digestible in the lower intestine. Research showed from Figure 1 that diets with different CP percentage in lactating cows had no effect on milk nitrogen output – which is milk protein and should not be confused with MUN. Furthermore, as the CP percentage increased in the diets the oversupply of N was excreted as manure (faecal & urine).

Urea is then produced in the liver from the excess ammonia and this process uses energy, energy which could instead be used for other requirements. Dairy cows are particularly efficient in recycling urea when fed low-protein diets. It has been proven by some feed systems in the UK that the efficiency of using protein for milk protein synthesis is better for diets which are deficient or marginal in protein than those which are adequate.

 

When looking from a nutritional point of view, the standpoint would be not to apply CP any longer, but still CP are being used by nutritionist and/or consultants probably due to fear of the unknown. Ipharraguerre and Clark, 2005 found a significant curvilinear relationship between milk yield and the concentration of CP of the diet on 112 research trials. As indicated in figure 2 diets on the same CP concentration varied in 20kg milk yield per day. Which means that if there is a decline in milk production it’s less expected to be from a CP concentration and more probably a decrease in DMI and/or diet digestibility.

 

Nutritional flushing of Sheep

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In recent times the economic pressure that sheep farmers have experienced has been detrimental. To relieve the pressure that farmers experience, flush feeding could be used as a management tool to maximize the economic viability of their sheep enterprise. The proper nutrition during the breeding season is key.

Flush feeding

Flush feeding is a well-known term used to describe the purposeful elevation in the level of nutrition of a ewe just before breeding. The aim is to increase the ewe’s weight with the objective of ensuring that the number of ewes that come into oestrus is maximized as well as boosting ovulation, conception, and embryo survival. Increasing these rates increases the lambing percentage by 10% – 20% which in turn is a primary factor that influences a sheep enterprise’s profitability. Ovulation rate and live weight are correlated traits when it comes to sheep but only until a threshold is reached. Research shows that the lambing percentage increases with 1.5% and the ovulation rate by 2% for every kilogram that the ewes in the herd are heavier during mating until of course the threshold point has been reached. Ewes that gain weight during the breeding season are more prone to produce twins than ewes that maintain or lose weight.

Body Condition

The focus for success with flush feeding should shift towards reaching an optimal body condition (BC) before and during the breeding season. The optimal BC falls between 3 – 3.5 on a scoring system of 1 – 5. The effectiveness of flushing is much higher on thin ewes because of their quicker response in body condition. Ewes with above average body condition usually do not respond as well to flushing as thin ewes. Managing the ewes by sorting them into different groups according to body condition could help save a lot of money on feed costs as ewes with above average body condition will need less feed to reach the optimal body condition than thin ewes.

Flushing – When and How

The period of flushing before breeding depends greatly on the body condition of the current herd. A group of ewes with a BCS of more than 2.5 will need about 3 weeks of flushing before mating while thinner ewes will need a longer period. Flushing should continue for another 3-4 weeks into the breeding season. This is to ensure that early embryonic deaths are minimized. Research has shown that continuing flush feeding into the breeding season causes embryo implantation and attachment to the uterus to be more successful, this is due to the increased amounts of energy received through flush feeding. It is of great importance not to continue with flush feeding for too long as it is not economically viable to feed the ewe above her maintenance needs for the rest of her gestation period until a month before lambing. Feeding the ewe to her maintenance needs will be more than enough.

 

Diet and nutritional changes

During the flush feeding period ewes should be allocated the highest quality grazing to stimulate weight gain and allow ewes to reach their optimal body condition. Ewes need a higher dry matter intake and require an increase in energy which should be the focus point when it comes to the ewe’s diet. As important as increasing the energy in the diet is, it is just as important to have high quality bypass protein in the diet. The next important concept is to have enough feed bunk space to allow all animals to consume the correct intakes when supplementing additional feed. It is important to remember that not one farm or supplemented diet is the same and one should consult with your nutritionist so that the correct recommendations and advice regarding your setup can be given.

 

Flushing rams

Rams should be flush fed 2 months prior to the breeding season to increase sperm production and testes size.  It takes 2 months for sperm to develop and mature. A bypass protein based flush feed is ideal to start rams on 2 months prior to mating. Rams play a critical role in ensuring a high lambing percentage and for that it is best to keep rams in an optimal body condition (3.5) so that their performance is maximized. Rams should not be allowed to get to thin or to fat. This has a definite negative impact on their performance and on the lambing percentage in the end

 

(By Andries Kruger, Technical Advisor, AFGRI Animal Feeds)

 

 

 

 

 

 

 

 

Nicci Oosthuizen: Proudly AFGRI, born and bred

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With the Covid-19 pandemic still in full swing and 2021 still in its baby shoes, many of us feel uncertain about the future. With so many dreams and goals for ourselves and our children, how do one navigate this year?

“A pessimist sees the difficulty in every opportunity,” Winston Churchill once said, “but an optimist sees the opportunity in every difficulty.”

The AFGRI Animal Feeds family has therefore made a promise to ourselves and our customers that despite these chaotic and uncertain times, we will live to the fullest and not give up on our dreams nor those of the next generation.

Celebrating success

In anticipation of a bright future ahead, we’re celebrating and sharing some of our AFGRI family’s achievements to motivate and inspire us all to continue chasing our dreams.

Nicci Oosthuizen, a grade 11 scholar at Afrikaanse Hoër Meisieskool, is the youngest netball player in history to have been selected for the South African under-21 team. The SA U/21 team is currently preparing for the Netball World Cup Junior League 2021, which will take place in Fiji this year.

Nicci’s achievement comes after a lot of dedication and practice. She enjoys her position as centre and has been playing netball since the age of nine years. Nicci is known by her team for her quick hands and ability to balance and control the game expertly. Nicci’s coach, Amanda Mynhardt, told News24 that what really sets Nicci apart is her brilliant mind.

AFGRI has also been the proud head sponsor of Meisies Hoër for the past few years. And Nicci, herself a family member from the AFGRI stable, wears the AFGRI logo on her netball dress with so much pride since it holds personal meaning for her.

 

Nicci Oosthuizen, our AFGRI baby achieving big dreams.

On behalf of the business and the AFGRI brand, I would like to again congratulate Nicci on her phenomenal achievement. Our prayer is that God will protect you from injury and fill you with strength and courage to use your talents and your full potential.

We’re proud of you Nicci!

Anina Hunter