Phosphorus is the most significant nutrient in short supply on green summer grazing. However, according to the latest research results and general problems experienced by farmers, trace mineral shortages are becoming more prevalent.
Zinc shortages are quite common in the summer crop areas. A zinc shortage can lead to embryonic deaths (poor conception), abnormal sperm formation, delayed testis development, poor immunity and a higher incidence of foot rot, especially in wet conditions. Copper shortages are relatively common and symptoms include anaemia, poor growth, low fertility, loss of wool crimp and black cattle exhibit a rust-brown coat, especially on the rump.
Manganese and selenium shortages also occur, but are less common than zinc and copper shortages. Selenium shortages are mostly found in heavier red soils. The four trace elements, zinc, copper, manganese and selenium, all play an important role in the fertility of farm animals. High producing animals such as a beef cow that calves every year and an ewe that weans at least one lamb per year, have greater mineral and trace mineral requirements.
The most popular method of supplementing these shortages, is by feeding Voermol Rumevite 6P (V11995) or a mixture of 50 kg salt with 50 kg Voermol Rumevite 12P (V11994). In cases where intake of these licks is insufficient, one can use the molasses-based, ready-mixed Voermol Superfos (V17422) or a mixture of 50 kg Voermol Rumevite 12P, 50 kg Voermol Super 18 (V355) and 50 kg salt. Due to the fact that molasses promotes palatability, higher intakes are achieved with these licks.
During the rainy season a loose lick in open troughs usually poses problems and lick losses are experienced. The Voermol Phosphate Block (V10264) is exceptionally well suited as a supplement under these conditions. It is easy to handle, lick intake is controlled and few losses are experienced. For example, a cow with a calf requires 200 g of Phosphate Block per day – put out enough blocks for a period of, for example, fourteen days, in order to control lick intake. It is not a problem if Phosphate Blocks are depleted before the period is over, as the body stores minerals and an animal can get along without the lick for a few days, provided that sufficient amounts were put out.
A basic mineral and trace mineral supplement is also applicable to green cultivated pastures. High levels of nitrogen fertiliser on cultivated pastures can lead to metabolic disturbances in animals, such as ammonia and nitrate poisoning. The mineral and vitamin metabolism is disturbed and leads to poor milk production, growth and reproduction. Although the crude protein content of fertilised pastures is high, it is also highly soluble and degradable, and relatively small amounts of protein reach the abomasum and small intestine. The energy value of these pastures is relatively low and animals don’t finish in the required time.
Voermol Molovite (V7266) is specially developed to supplement nutritional shortages on fertilised cultivated pastures. It is recommended for the finishing of weaner calves or animals with a high nutritional requirement such as first-calf heifers or phase D bulls in a semi-extensive grazing test. Molovite is an energy supplement with 10% crude protein and is NPN-free. It is ready-mixed and can be used as is. It contains very little salt, is molasses-based which ensures good intake, and contains medicaments which improve the utilisation of energy on pastures.
During development trials Molovite outperformed a standard phosphate supplement and improved the growth of weaner calves by 62%. The recommended intake of Molovite is approximately 1 kg per animal per day and 200 g per sheep per day. In order to finish animals (put on fat) quicker, Molovite can be mixed in equal parts with grain meal. Feed 2 kg of the mixture per animal per day and 400 g per sheep per day.
A characteristic of summer grazing is that production and quality are incidental to rainfall. The summer rainfall areas are characterised by intermittent, shorter drought periods during which the quality of the veld deteriorates quickly and growth in weaner calves, for example, slows down. In order to counter the effects of variation and deterioration in summer veld quality, Voermol Supermol (V7267) is recommended as a a production lick.
Supermol is a protein, energy, mineral supplement containing 20 % crude protein. It is recommended for the finishing of weaner calves on summer grazing or for animals with a higher nutritional requirement, such as cows in the breeding season. Supermol is effective as a flush lick 21 days prior to the breeding season and a further 21 or 42 days during the breeding season. The recommended intake of Supermol is 1.2 kg per animal per day. It can also be mixed in equal parts with grain meal to finish calves quicker. Feed a maximum of 2.5 kg of the mixture per animal per day and ensure that there is enough feeding space so that all animals can feed at the same time.
To summarise: The basic supplements on green summer grazing are phosphate and trace minerals. For animals with higher nutritional requirements, such as weaner calves or first-calf heifers before and during the breeding season, use Molovite on fertilised cultivated pastures and Supermol on veld grazing.