Bos Taurus Dairy Research Articles

Effects of amount of milk, milk flow and access to a rubber teat on cross-sucking and non-nutritive sucking in dairy calves

The aim of this study was to test the effects of different amounts of milk, flow rate of milk, and access to a teat after milk intake on non-nutritive sucking on an empty teat and on cross-sucking on other calves in Bos taurus dairy calves. An additional aim was to test if calves prefer to perform non-nutritive sucking on a teat with the taste of milk or on a clean teat. First experiment involved 11 groups of three calves during gradual decrease from 5 to 2.5 and 1 to 0 l of whole milk per meal twice daily. Milk flow was either 0.5 or 1 l/min, and the teat buckets were either left or removed after milk intake. When the calves were fed with 5 l of milk, non-nutritive sucking and cross-sucking decreased ( P<0.001), compared to 1 and 2.5 l. Removing the empty teat after milk intake increased cross-sucking ( P<0.001). Slow milk flow reduced non-nutritive sucking after milk intake ( P<0.05), but did not influence cross-sucking. Duration of recorded milk intake was similar with fast flow and 5 l of milk, compared to slow flow and 2.5 l of milk. The latter combination increased non-nutritive sucking and cross-sucking, suggesting that amount of milk is more important than duration of milk intake. Second experiment was carried out on 12 individually kept calves. The calves received 2.5 l of milk either in an open bucket, in a rubber teat bucket, or half/half in both buckets. When not used for feeding, the open bucket and the teat bucket were filled and emptied again to make them ‘tasty’ with some drops of milk. The tasty teat bucket was either removed or present after milk intake. The calves had always access to a second clean teat bucket. Source of milk had no influence on recorded behaviour after milk intake. The tasty teat was sucked for twice as long as the clean one when both teats were present ( P<0.001). When the tasty teat was removed, the calves increased sucking on the clean teat ( P<0.001), but decreased total time spent sucking ( P<0.001). We conclude that a high amount of milk and the presence of the teat bucket after milk intake reduces cross-sucking, and that a clean teat is less effective in encouraging calves to suck than a teat with taste of milk.

Large Scale Crossbreeding of Bos Indicus with Bos Taurus in the Tropical Rain Forest Climate of Kerala in South India

The state of Kerala in India has predominantly an agrarian economy, with crop production providing the major income for farmers. The economy is also supported by animal husbandry in many of the farm households. Geographically Kerala lies in the tropical rain forest belt with a two season pattern and two monsoons spread over eight months. The main food crops are paddy and tapioca, while the cash crops grown are coconut, rubber, pepper, cashews, tea, coffee and spices. The population density is one of the highest in the world with 654 people per km2, therefore placing extraordinary pressure on land availability for crops and cattle. The native non-descript zebu-type cattle of Kerala, evolved over long periods, are poor in milk and reproductive performance but have adapted very well to the tropical environment with regards to heat and disease resistance. The local zebu are small in stature with an average body weight of 150-250 kg standing 1.1-1.2 meters high. The average age at first calving is 51 months and the average lactation yield is estimated at 500-700 kg/200 days.1,2 The average calving interval is long at 21 months2. The number of AI per conception is 2. 4 for field animals2.These non-descript zebu type cattle could not satisfy the milk needs of the state. To improve the milk production to 1500 L per lactation by genetic improvement alone would have taken 150-200 years. Replacement of local stock with exotic dairy breeds was not practical. Past experience has shown that transplantation of such temperate breeds into the tropical rain forest climate is not economical because of poor adaptability, susceptibility to tropical diseases and non-availability of suitable management. Therefore, a programme of limited crossbreeding of local zebu cattle with Bos taurus dairy breeds was implemented as a practical means enhancing the milk yield. Crossbreeding offered the most promising approach to evolve a type of cow which could be maintained economically under prevailing village conditions. The purpose of this paper is to present data supporting crossbreeding between local nondescript milk breeds with top genetic material of temperate Bos taurus milk breeds, as the best currently available means to converse local poor producing cattle into crossbreds of high productivity.

The genetic improvement of cattle in developing countries

A summary of published results from crossbreeding local Bos indicus breeds with improved Bos taurus dairy breeds in the tropics is presented. This shows consistent improvement in age at first calving, first lactation milk production, and calving interval, up to 50% Bos taurus. Higher percentages of Bos taurus, in general, were not much better, and for calving interval, tended to be poorer than the F 1. A model involving additive genetic differences between breeds, and heterosis effects, adequately describes the results and provides a basis for planning further generations. In most cases, it suggests that a composite or synthetic population should be the ultimate aim. The potential of a range of new technologies for improving animal production, and particularly for enhancing genetic change, is reviewed. Embryo transfer in nucleus herd breeding schemes seems to offer special promise in developing countries. If low cost embryo production becomes possible, through in vitro fertilisation or embryonic cloning, widespread use of the technique might be justified to provide a continuous supply of taurus - indicus F 1 animals. Routine sexing of semen or embryos would further enhance the prospects for this development.

Some skin characters in five breeds of European (Bos taurus) dairy cattle

Observations were made of a number of skin characters in five breeds of European (Bos taurus L.) dairy cattle. Skin samples were taken from the cattle in January and July. There were differences between breeds in sweat gland volume and length! diameter ratio, in skin and papillary layer thickness, in the ratio skin thickness/papillary layer thickness, and in the degree of shrinkage in transverse sections cut from the papillary layer. There were no differences between breeds in density of follicle population (and hence sweat glands) per unit area of skin. Sweat gland volume, skin thickness, and papillary layer thickness were larger in winter than in summer, but there were no such differences for sweat gland length/ diameter ratio, the ratio skin thickness/papillary layer thickness, and follicle population density. The only significant overall correlations between characters were those between sweat gland volume and sweat gland length/diameter ratio, and sweat gland volume and papillary layer depth.