Blog 3 Dairy cow Louise1946: heredity and genetic predisposition
Dairy Campus in Leeuwarden is the innovation center for dairy farming and the dairy chain. The 500 dairy cows are indispensable to realize our mission. In addition to milk, they mainly produce data. Louise1946 is one of these cows. We follow her in this blog.
Louise1946 was born on March 10, 2018 and named after Prof.dr.ir. Louise O. Fresco, chairman of the board of Wageningen University & Research. The number 1946 is her work number and is part of her life number as stated in her passport. In this bi-monthly blog we give an insight into the state of affairs at our center and what happens to our animals on the basis of her activities. The first blog stated that Lousie1946 gave birth for the second time to a healthy calf, Ymkje Louise, on December 19, 2020. In the following blog [blog 2] we described this gestation and birth. In this new edition we will discuss the heredity and genetic predisposition of Louise1946 and her descendants.
Cow of the future
A livestock farmer wants healthy cows that produce sufficient milk with good components. The DNA of the cow is very decisive in this. Are the genes dominant or recessive? And is the cow homozygous or heterozygous for a hereditary trait?
The aim of breeding is to develop a dairy cow that gives a lot of milk with a high fat and protein percentage, that lasts for a long time, is animal-friendly to manage, is fertile and efficient and goes through life in good health. In short, a long productive life. The aim is that the daughters are an improvement compared to the mother.
In addition to the genes a cow has, the environment is important: the feed she is given, the barn she is housed in; all this is of great importance. Her living environment has a major impact on performance and how much of her genetic potential she can achieve.
In this blog we focus on the genes of Louise1946 and her descendants.
This report by Louise shows that her claw health and fertility are better than average, because her breeding values are above 100. The breeding values for CRV health and efficiency also show that she performs better than the average dairy population in the Netherlands: for Health 5% better and for Efficiency 2% better. The report also shows that her protein percentage is lower. This is a characteristic to take into account when choosing a bull for her offspring, because ultimately we want cows in the barn that give a lot of milk with a high fat and protein percentage.
Louise1946 has a good breeding value for fertility (104, so >100, so better than average). This is also reflected in practice, because within 60 days of calving her second calf, she was successfully inseminated again with semen from CRV bull Gladiator. Her third offspring is expected around November 17, 2021.
In the meantime Louise1946 has produced two cowcalves, both born in the year 2020; 3022 in February and 3498 in December. The bull selected for this gives higher percentages (positive numbers) on the fronts where Louise scores less than average. The goal and the expectation is that her offspring will have higher breeding values, because in the end half of the genes come from the mother and the other half from the father. Before we genotyped the animals, we didn't know exactly what DNA an animal had. In other words, what half of the genes she had inherited from the mother and from the father. So if Louise were to be mated twice with the same bull, both offspring would have the same breeding values at birth. But through genotyping, we know exactly which DNA the animal has, and with that we can also make a better estimate of its genetic predisposition.
Based on this, we expect the offspring to have higher levels than Louise1946. In theory, they could have 'bad luck' with unfavorable genes she gets from her father and mother, and so she will also have negative values on her breeding list.
|Louise1946||Daughter 1 (3022)||Daughter 2 (3498)|
The numbers in the table above show that by inseminating Louise with a selected proven bull from CRV (Bouncer) a progeny (3022) is born that, because it is now of course still a heifer, will have a higher protein percentage in her milk than the average dairy population. So Louise's lesser performance (lower protein percentage than average) has been improved in her offspring through the right bull choice. Other important attributes such as health and efficiency will also outperform Louise's performance. So far, milk production has lagged far behind, which is a big difference.
By inseminating Louise1946 with the same father (Bouncer), another offspring (3498) was born. Her protein percentage is also expected to be higher than average and thus an improvement over her mother's performance. Her efficiency will also be better, but she will be slightly more susceptible to mastitis than her dam, but still less sensitive than the average dairy population (because the breeding value is still >100). Milk production is just like the mother, but unlike the first daughter, high.
Reducing methane emissions
The goal of breeding is to make the next generation better than the current generation. Wageningen Livestock Research, led by breeding expert Yvette de Haas, is currently investigating the possibility of gradually reducing methane emissions from cows through breeding. In the project 'Genetic possibilities to reduce enteric methane emissions from dairy cattle', the differences in methane emissions between animals and their heredity in cattle are mapped out.