Practical Cattle Farming

Kat Bazeley, Alastair Hayton

• Éditeur: Crowood
• Année: 2013
• ISBN:
  9781847975850
• Sujet: Tecnologia e ingegneria
• Sous-sujet: Allevamento di animali

Practical Cattle Farming is written by two experienced, practising veterinarians, and covers the essential elements of beef and dairy cattle farming and the latest cutting-edge scientific research, and is therefore of value both to the novice and to those with experience. The text is clearly written and includes helpful explanatory notes and detailed practical information. Examines the principles of beef and dairy production, and the husbandry of cattle from the newborn calf to adulthood. Explores the practical aspects of nutrition, housing, grazing and fertility management including the common problems, how these may be identified and corrected, and some of the economic factors that must be considered. Analyses the principles of disease prevention and control in order to maximize the success of the cattle unit. Outlines the factors that determine the welfare of the cattle and the relevant English laws. Essential reading for all beef and dairy cattle farmers, those working in industries associated with cattle farming, and agricultural and veterinary students. Provides practical guidance on all aspects of cattle farming. Fully illustrated with 150 colour photographs and 40 diagrams and drawings. Kat Bazeley and Alastair Hayton are two experienced, practising veterinarians.

CHAPTER 1

Dairy Farming Systems

There have been major changes in dairying in the last thirty years, with both average herd size and milk yield increasing significantly: there are now many herds of 500-plus cows producing 12,000–14,000 litres per lactation. These increases in milk production have occurred as a result of changes in the world markets and have been made possible by improved genetic merit as well as better understanding of dairy cow nutrition and computerized ration formulation.

There are a number of different designs of milking parlour. This rotary parlour is expensive to install but since it enables two operators to milk 150 cows per hour it is well suited to a large herd.

However, increased yield and larger herd size have been accompanied by a variety of problems that cause economic losses, and in some herds the losses are so high that they outweigh improved performance. For example, despite intensive research there has been no progress in reducing the incidence of mastitis or lameness in dairy herds, with average incidence for each disease running at over 20 per cent (and in some herds at more than 50 per cent). Despite technological advances that should improve fertility management, fertility results are deteriorating, and the number of forced culls is increasing, with many cows culled in their first or second lactation. This represents a great waste of potential and investment.

A typical cow’s lactation curve rises to a peak at six to eight weeks after calving; in the following months it gradually falls until weaning or drying off.

The challenge to every dairy producer is therefore to achieve the most cost-effective milk production for his or her own unit. This is not necessarily accomplished by producing the highest possible yield, but by making best use of the resources available: farm location, land quality and acreage, housing, skill and availability of labour, genetic potential of the herd, management and capital.

This chapter explores the principles of dairy production and the factors affecting its costs.

DAIRY SYSTEMS

A number of factors influence herd milk yields, and farmers may choose anything from a low-input–low-output system to a high-input–high-output system. Low-input–low-output herds are almost invariably based on spring-calving grazing systems: they rely on a low purchased-feed rate and try to produce the bulk of their milk from grazed grass. Average yields are around 4,500–6,000 litres per cow per year, so metabolic stress on cows tends to be low, with low incidence of disease and fertility problems, and a low culling rate. At the other extreme, high-input–high-output systems are based on housed cows that are fed high levels of concentrate. They require careful ration formulation and tight fertility management. Yields will be high, ranging from 8,000–12,000 litres per cow per year in the UK, and higher in the United States. Metabolic stress on the cows tends to be high. Either system can work to generate a profitable dairy enterprise, provided that management is good and targets are met. The key difference is that grazing-based systems are weather dependent, whereas high-yield systems can provide total control over feed supply, which reduces risk and variability.

The effect of calving interval on milk yield. A prolonged calving interval leads to a long period of low production and prolonged dry period. The cow that calves regularly produces significantly more milk per year.

MILK PRODUCTION

For the first days after calving the cow produces colostrum to provide her calf with antibodies that protect it from disease (see also Chapter 3). The colostrum changes to normal milk by the fourth day after calving. The calf is generally removed from the cow about twenty-four hours after birth (the calf should not be removed earlier because it will not have received as much colostral protection as it needs); in some herds calves remain with cows for longer.

Provided that everything is normal, the cow is ready to join the milking herd within one to four days after calving. Yield increases rapidly, with peak lactation of more than 60 litres daily for high-yielding cows. The transition from dry to peak yield therefore represents a very high metabolic challenge and, not surprisingly, is associated with the highest incidence of disease and weight loss.

Most milk is produced in early lactation, so it is essential that the cow calves regularly (see the graph on page 9). It is generally most cost efficient if s...