The best strategies to achieve the maximum weaning percentage
In Argentina, recurrently the conflict between the countryside and the government arises strongly over the price of meat. Generally, these moments of crisis are caused by a mismatch between the available supply and the instantaneous demand generated by consumption and exports.
Looking to the future, demand can only grow hand in hand with the increase in population and the growth of world trade, fueled by the demand of the countries of the East and Europe. Then, To prevent the recurrence of conflicts, the only thing left to do is to increase supply, a process that can be carried out in two ways: increasing the weaning percentage in breeding herds or increasing the slaughter weight of the steers. In this note we will refer to the first way, because there is a lot of room for progress and new low-cost technological tools that allow improving the physical and economic results of companies.
The percentage and weaning weight are the indicators that most impact the profitability of breeding herds. In Argentina, the stock has more than 52 million heads, of which 23 million are cows and 7 million heifers (Senasa, 2020). Therefore, Calf production is an activity of great importance for the country’s economy. But nevertheless, weaning percentages rarely reach 85% and the national average is closer to 65%.
To maximize the weaning percentage, it could be considered, in a situation of maximum efficiency, a pregnancy percentage of 95 in three months of service, 5% pregnancy loss and 5% weaning loss. Listed below are the various factors that must be taken into account to achieve these superior results.
During the service, the keys to achieving a high pregnancy rate are proper oestrus stimulation, rapid uterine involution after delivery, correct nutritional status, and proper health and fertility of the cows, added to one high fertility of bulls at the beginning of the breeding season.
The first step in carrying out the process is to record the events with a detailed procreation sheet, and where possible, with software that allows us to load the information. we must have a good identification of the animals and the corresponding daily parts.
It is necessary to specify how many cows enter the service and from there to weaning, record all events (pregnancies, abortions, sales and deaths) in order to assess where losses occur. Electronic caravans, reading sticks and monitors with automatic loads, added to scales, are available tools that will become increasingly necessary to streamline these processes.
Parking services for 75 to 90 days is key to being able to manage the forage resource according to the needs of the cow and to be able to control reproductive infectious diseases at the right time.
Without service parking it is almost impossible to determine where losses occur and select the most fertile cows. Already well-known techniques such as nutritional flushing, pharmacological induction of heat and early weaning are valuable tools to achieve more concentrated services and with a greater calving “head”.
Bulls must be checked prior to breeding with a fertility test. by the veterinary doctor and declared fit. This includes physical examination, genital examination, and tests that indicate the breeder is in good serviceability and disease free.
Venereal diseases (trichomoniasis and campylobacteriosis) and abortigenic diseases (brucellosis, DVB, IBR, leptospirosis, neosporosis, etc.) are the main responsible for losses during pregnancy.
However, genetic aspects, metabolic deficiencies and toxic causes cannot be ignored as partial culprits. The incorporation of PCR (polymerase chain reaction) has increased the diagnostic possibilities for venereal diseases and other reproductive conditions, and allows the identification and shelter of positive animals.
Nutritional aspects during the gestation period have also been the subject of studies in recent years. A common practice of our rodeos was to restrict the cows during the winter, a restriction that is sometimes forced by the conditions of the field and the lack of rain. But nevertheless, Recent studies have suggested that nutritional aspects during pregnancy could affect the offspring’s genome, altering its future reproductive physiology.
Although the objective to be achieved is a 10% loss between pregnancy and weaning, values of 20% in herds of first calving heifers and 15% in cows are common numbers to observe. Early pregnancy losses are the most important, since after natural service or artificial insemination, fertilization occurs in almost 95% of cases.
But nevertheless, only 50% of conception is detected 40 days after service. The possibility of measuring PSPB (pregnancy-specific protein) from 23 days after artificial insemination and performing ultrasound scans at 30 days have made it possible to determine the losses in these periods and seek strategies to reduce them. Without a doubt, balanced nutrition throughout the period and vaccination against reproductive diseases are some of these strategies.
In general, calving in breeding cows occurs in extensive conditions where monitoring is not possible. However, it is necessary for operators to be trained to correctly assist wombs with delivery problems. Late abortions, stillbirths and perinatal deaths are very difficult to differentiate and a plan monitored by a veterinarian is necessary, including a detailed survey of the information, with trained scouts to record the events and be able to determine where the losses occur.
On the other hand, The possibility of predicting parturition is a very important limitation in cattle farming. Australian researchers have reported that automatic weighing systems in restricted areas, where cows access water, managed to predict the time of calving in 63% of the cows. In turn, the possibility of measuring gestation length allows selecting bulls that reduce the calving interval and therefore improve the problem of postpartum anestrus.
The chances of calf losses from calving to weaning (discounting perinatal deaths) are lower; however, they should not be neglected. Neonatal calf diarrhea and bovine respiratory complex are diseases that can cause casualties in this period. For this, Vaccination of mothers with two separate doses three weeks prior to delivery is an effective prevention strategy. In addition, we must be attentive to diagnosis and treatment of patients, and ensure the conditions of food and general management to complement these measures.
Without a doubt, Genetic selection is the future in animal production systems, not only because it can give rise to more efficient animals from the productive point of view and better meat quality but because, as is being demonstrated in dairy cattle, could generate more fertile and disease-resistant animals. This marks a huge future for livestock in food production and places the artificial insemination (in addition to other techniques such as embryo transfer and in vitro fertilization) as fundamental tools in this process.
Advances in synchronization of estrus and ovulation in beef cattle allow cows to be synchronized 10 days before the start date of service, and on the same day a large number of animals can be inseminated with a bull of high genetic quality.
In addition to genetic improvement, this technique can contribute to inducing heat in animals in anestrus, on certain occasions. The application of this technology has shown that it produces improvements in weaning weight on two sides: due to genetic improvement and due to the earlier birth of calves.
Nowadays, there are synchronization protocols that use very safe drugs for the consumer and the environment, that allow synchronizing the animals to be able to apply artificial insemination in situations of extensive management. The combination of artificial insemination at a fixed time with revision with bulls or with resynchronization can improve reproductive efficiency and contribute widely to improve the percentage of weaning.
The author is responsible for Reproduction at Select Sires & Juan Debernardi