THE IMPORTANCE OF COW PRODUCTIVITY IN BEEF CATTLE
Dr Vlok Ferreira, Technical Executive, Molatek
The Heritable traits that can influence cow productivity is:
1. Weaning weight of the calf
2. Feed requirements of the cow-calf combination (per LSU- Large Stock Unit)
3. The rate at which calves are born (indicated by means of inter-calving period – ICP)
How to Calculate Calving percentage and Cow Productivity:
Calf % = 100 – ((Inter-calf Period – 365 days)/365 X 100)
Example:
Inter-calf period: 420 days
Calf % = 100 – ((420 – 365)/365 X 100)
= 84.9%
Cow productivity = (Weaning % X weaning weight at 205 days)/LSU [we assume that the calving percentage is equal to the weaning percentage]
Example:
Weaning weight at 205 days: 210 kg
Cow productivity = 0.849 X 210/1.45 LSU
=123 kg
Easing the shock of weaning:
Removing the calf from its mother is a necessary procedure, but also one that unfortunately lowers the productivity of the calf. For the first 14 days after weaning, the calf will likely experience a drop in body weight due to stress and lack of eating, if the weaning process is not properly managed.
The use of a creep feed as a management tool, to ease the weaning shock helps. Creep feed is a way of introducing feed to the calf whilst it is still suckling. Getting used to eat out of a feed trough before being weaned is one way to ensure that body weight is maintained during the weaning process, as the calf will already be used to eating feed.
How improving cow productivity reduces environmental impact:
The differences in cow productivity of a South African beef breed were examined from 1980 to 2013 (Jordaan 2015). The aim of the evaluation was to investigate the effect of cow productivity and the different components that influence cow productivity (weaning weight, weight of the cow, and inter-calving period) have on the environment.
Definition of LSU (Large Stock Unit):
The equivalent of an ox with a weight of 450 kg, that has a daily gain of 0.5 kg/day whilst on grazing, and that has a digestible energy of 55% and 9 kg intake of grazing per day.
In South Africa the enteric methane emissions factor (MEFenteric) of one LSU is 94 kg methane/year.
The relative contribution of the 3 components (weaning weight, cow weight and inter-calving period) to cow productivity and the resulting environmental impact were investigated. This was managed by changing one of the three factors by 5% while keeping the other two factors constant.
Results:
The cow productivity of the beef breed measured in 1980 was 94 kg weaned calf per LSU mated, with the MEFenteric of a LSU measured at 94 kg methane per year.
The resultant conclusion: MEFenteric = 1 kg of methane produced per kg calf weaned/LSU mated. In other words, every kg of weight on a weaned calf per LSU mated, resulted in 1 kg of methane being produced.
The cow productivity for the same beef breed measured in 2013 was 107 kg weaned calf per LSU mated, with MEFenteric of 0.88 kg methane per kg calf weaned per LSU mated. In other words, every kg of weight on a weaned calf per LSU mated, resulted in 0.88 kg of methane being produced.
The genetic improvement of the beef cows in this investigation showed a decreased cow weight, a 20 day decrease in the intercalving period and a 20 kg increase in weaning weight. This improvement of the productivity of the cows decreased the carbon footprint by 12%, between 1980 and 2003.
This is comparable to another investigation conducted by Capper (2011), indicating that beef cattle in the USA had a decrease of 16% in their carbon footprint from 1977 to 2007.
The importance of improving the calving percentage of our national herd by about 62 – 65% is illustrated by the relatively large environmental impact that fertility has, when looking at intercalving-period as a measurement. The relatively large positive environmental impact of an increase in fertility (as reflected by ICP) illustrates how important it is to increase the relatively low calving percentage of the national beef herd (~ 62 – 65 %).
A higher weaning weight, a higher weaning percentage and a lower inter-calving period decreased negative effects on the environment, and this is what beef cattle producers should be aiming for, with optimal cow productivity in mind.
Notable result: When the inter-calving period was decreased by 5%, overall cow productivity improved with 7.3 percent.
What this means is that more calves are weaned, and that inter-calving period should be decreased as much as possible to experience the largest effect, resulting in highest productivity and highest output.
How the age of cows influences productivity:
Age, weight and breed all have an impact on the age at which a heifer will reach puberty.
Age: The goal of many producers is to have heifers calf for the first time at 2 years of age. For this to happen, the heifer should reach puberty at 12 – 15 months of age. This will also depend on the breed of the cow. European breeds reach puberty at the age of 12 months, where breeds in South Africa generally reach puberty at the age of 14 – 15 months.
Weight: Weight is the factor that most influences puberty, and a heifer will reach puberty when she weighs 65-70% of her potential mature body weight.
Breed: Larger, late maturing breeds will reach puberty at a later stage than early maturing breeds and will generally have a calving age of 27 months rather than 24 months. The average weight will differ for each breed.
Age at first heat:
Heifers need to have an average daily gain of 800g/day from weaning to first service or have a total gain of 115-160 kg during the first winter — approximately 200 days.
For most breeds this means that the crossbreed heifers need to weigh between 295 and 385 kg. Crossbreeds normally will reach maturity at an earlier age than either of the parent breeds. Heifers who have a greater daily gain will reach maturity at a younger age than heifers who do not have a sufficient daily gain.
Age at 1st calving:
Heifers that calve at the age of 2 years and then calve every following year, will produce +-330 kg more weaned calf weight than if they calved for the first time at 3 years of age over a lifetime basis.
Therefore, cows should reach an optimal weight to reach puberty in a timely manner, but that breed effects will have a large influence in what this weight should be. A cow that calves for the first time at the age of 2 years will have an increased productivity.
Proper nutrition is not to be underestimated when it comes to the conception rate of heifers:
In a herd of 98 heifers, the average weight of the herd was 341 kg. It was found that 63 out of the 98 cows (64%) conceived when they had a weight of 350 kg at service. Those animals that did not conceive (36% of the herd) had an average weight of 327 kg at service.
As we can see, the weight at mating has a direct impact on whether the heifer conceives or not and the health and body condition of the cow is highly important when it comes to mating.
The effect of body condition score (BCS) on conception rate:
It was found that for a cow to conceive during the next cycle, it is optimal for the cow to have a body condition score of 3.5 at calving on a scale of 1 is thin and 5 is fat. This had a resulting conception rate of 80%.
Similarly, body condition score during mating had an influence on the conception rate, with a BCS of 3.5 resulting in a conception rate of 100%.
This proves that the optimal BCS for a cow to conceive, both at calving and at mating, is a score of 3.5. It is of utmost importance that the body condition score (BCS) not be too low, as it will prevent the cow from conceiving.
Heifer Nutritional Requirements:
A heifer’s nutritional requirements are going to depend on the size of her body frame and her weight. Logically, it makes sense that an animal with a larger frame is going to have slightly higher requirements than animals that have a smaller frame.
Supplementing heifer diets:
Working on the assumption that the heifer weighs 400 kg and is grazing on winter veld (4.17% protein), she will have a daily intake of 7.2 kg of grazing, of which 300 g is protein and 3 kg is TDN (Total Digestible Nutrients) and 6.3 MJ ME/kg pasture.
Since the heifer’s protein requirements need to be met, the protein content of the grazing needs to be calculated. Crop residues in winter are low in protein, and a protein supplement will be needed to ensure that no nutritional deficiencies develop.
Suggested supplementation includes:
• 250 – 300 g Protein/day
• 1 – 1.5 kg TDN/day
• 12 – 18 MJ ME/day
• 3 – 5 g Phosphorous/day
First calf feed requirements:
A first calf heifer will be smaller than a mature cow but will have nutritional requirements very similar to that of a mature cow because she is still growing, carrying a growing foetus and producing milk. In fact, the protein and calcium requirements of a first calf heifer will be higher than that of a mature cow.
Many supplementation practices are ineffective for heifers:
The intake of standard winter protein licks for maintenance by heifers is too low, and very often the importance of trace minerals is overlooked, and supplementation is inadequate. A USDA study found that only 8% of beef farmers that sent in feed samples for analysis indicated that the poor performance of their animals could possibly be linked to insufficient trace minerals in the diet.
The effect of phosphate supplementation on heifer performance:
The proper supplementation of phosphate is undeniably important in ensuring a proper calving percentage. Not only has phosphate been linked to weight gain, but also to an improved calving rate. If no phosphate is supplemented, the calving percentage of the herd in a trial was 52.9%, with cows calving every second year only. The lack of phosphate means that cows spend the year not in calf building up their phosphate reserves again. If cows are properly supplemented with phosphate, the calving percentage increased to 75.6%. Not only does their dry matter increase by 25%, but their body weight at calving increased with 15% as well. The average daily gain of cows with proper phosphate supplementation has been shown to increase with 130 – 320 g/day.
Cattle grazing on pasture, specifically young, green pasture, should be supplemented with a source of phosphate, like a Molatek Foslick (V16059) or Fosblock (V22502). Veldt pasture is phosphate-deficient, resulting in a deficiency in the diet of the cow.
Conclusion:
1. The environmental impact of producing beef cattle can be decreased
2. The results emphasise the importance of focusing on
a. Fertility
b. Identifying the reasons for low calving percentage, such as age at first calving; body condition score (BCS) and lick supplementation practices
Should you have any questions or concerns regarding how to properly feed your bull herd during the winter months or preparing them for an auction, contact your Molatek Technical Advisor.
