NZ521969A - Determining changes in milk production as a result of changes in milking frequency from a twice daily schedule to a once daily schedule - Google Patents

Abstract

A method for determining the extent of production change of animal prior to altering milking frequency comprises the steps of collecting milk from the animal, assaying the milk to determine the level of a given milk component present and comparing that level to reference levels indicative of production from animal milked at a particular frequencies. Preferably the method is used to determine the optimal daily milking frequency of an animal for any given production variable and the milk component is lactoferrin, serum amyloid protein or lipopolysaccharide binding protein.

Description

5219 69 InteHectual Property Office of NZ OCT 2003 received PATENTS FORM NO. 5 Fee No. 4: $250.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 521969 Dated: 15 October 2002 James & Wells Ref: 120626/28 DETERMINATION OF PRODUCTION We, AgResearch Limited, a New Zealand company duly incorporated pursuant to the Crown Research Institutes Act 1992 and having its Registered Office at 5th Floor Tower Block, Ruakura Research Centre, East Street, Hamilton, New Zealand hereby declare the invention for which we pray that a patent may be granted to me/us, and the method by which it is to be performed to be particularly described in and by the following statement: Our Ref: 120626/28 DETERMINATION OF PRODUCTION TECHNICAL FIELD This invention relates to a method of determining levels of production.

In particular, the present invention relates to the determination of production in 5 animals milked at a particular frequency, in terms of daily milk yield.

BACKGROUND ART In general, most dairy herds in New Zealand are milked twice daily, routinely early in the morning and again late in the afternoon.

Dairy animals in New Zealand are typically pasture grazed. Thus, to produce high 10 yields of milk, the animals require the maximum amount of time with which to graze and obtain food.

The breeds of dairy animals farmed in New Zealand also typically produce maximum milk yields when milked twice daily.

Twice daily milking is however both labour and resource intensive, not only in the total 15 number of hours worked, but also the time of day that animals must be milked.

In other countries such as Europe and the United States, it is common for animals to be milked three or more times daily.

This is due to some extent on the breeds of animal milked, but mostly due to differing farm practices and economic conditions.

Outside New Zealand, herds are typically smaller, with animals housed for large periods of time in barns during winter months. As such, animals do not need to be brought in from pasture to milking sheds, having feed supplied to them.

Our Ref: 120626/28 2 Such practices allow more frequent milking or automation such as robotic milking.

Further, higher payments for milk mean even small increases in milk yield from animals milked three or more times daily may be cost-effective.

However, these farm practices are not cost effective in New Zealand as the returns 5 from milk products are so low.

Many studies have been conducted into once daily milking, given the potential savings benefits in both labour and associated shed costs.

These studies have however shown that one characteristic of once-daily milking is a reduced milk yield. Another characteristic of once-daily milking is the accelerated 10 regression of the udder, leading to an increased rate of decline of milk yield as lactation progresses. As such, the declines in milk yields exhibited by once-daily milking means these practices are not commonly employed in New Zealand.

Despite these concerns, there is still scope for altering milking frequency in dairy animals, depending on the level of production loss.

All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior 20 art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.

It is acknowledged that the term 'comprise' may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this 25 specification, and unless otherwise noted, the term 'comprise' shall have an inclusive Our Ref: 120626/28 3 meaning - i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term 'comprised' or 'comprising' is used in relation to one or more steps in a method or process.

It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.

Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.

DISCLOSURE OF INVENTION According to one aspect of the present invention there is provided a method for determining the extent of production change in animals milked at a particular frequency, characterised by the steps of a) collecting milk from the animal, b) assaying the milk to determine the level of a given milk component present, and c) comparing the milk component levels to reference levels indicative of production from animals milked at particular frequencies.

The term "production" should be taken to mean daily milk yield, though it should be 20 appreciated this may refer to a number of milk variables such as milk volume, milk composition, fat content and so forth.

Daily milk yield may be determined based on the level of total milk solids in the milk; or alternatively by the total liquid volume of milk collected.

Our Ref: 120626/28 4 In preferred embodiments of the present invention, the method will be used to determine the extent of production change in animals prior to changing from a twice-daily milking schedule to a once daily milking schedule.

However, it should be appreciated this should not be seen as a limitation in any way. 5 It is anticipated that the present invention may be used to determine the optimal daily milking frequency of an animal for any given production variable.

The term "particular frequency" refers to the number of times an animal is milked per day, and may be once, twice, three or more times daily.

In preferred embodiments of the present invention, the animals of interest are cows. 10 However, this should not be seen as a limitation as it is anticipated that this method may also be applicable to other milk producing animals such as goats, sheep and so forth, including humans.

The term "assay" may be any experiment or diagnostic test conducted to determine the concentration or activity of a milk component. This can include tests such as 15 ELISA, Bradford or Lowry protein assays and so forth. Such assays are well known and it is anticipated that a skilled addressee would easily be able to match a given assay to the milk component of choice.

The term "milk component" should be taken to mean any component present in the milk, including enzymes, proteins, hormones, cells, ions, nucleic acids and so forth.

In preferred embodiments of the present invention the milk component assayed for is an indicator of lactoferrin content. More preferably, the milk component is lactoferrin protein. However, this should not be seen as a limitation as a wide range of milk components could conceivably be used for the present invention, including other indicators of lactoferrin, or other proteins such as serum amyloid, lipopolysaccharide 25 binding protein, and so forth.

Our Ref: 120626/28 The term "levels" can be any relevant measurement for the milk component of interest, but in preferred embodiments of the present invention the term "levels" shall refer to the concentration of lactoferrin in the milk.

Lactoferrin is a component of milk whey, valuable for its properties as an iron binding, 5 bacteriostatic and anti-bacterial protein. Lactoferrin concentrations commonly vary throughout lactation, being high in colostrum and in late-lactation milk, but low through mid-lactation.

Lactoferrin concentrations in milk have been found to be markedly increased during mammary involution when expression of the lactoferrin gene is initiated in milk-10 engorged, secretory alveoli of the udder.

A feature of once-daily milking is the accelerated regression of the udder as lactation progresses, leading to an increased rate of decline of milk yield.

These changes in milk composition are commensurate with changes that occur at drying-off.

In this regard, the inventors have previously shown that changing animals to a once daily milking regime was a useful means of differentially increasing the yield of lactoferrin from milk (Farr et al, Proceedings of the New Zealand Society of Animal Production 62. pp 225-236). The increase in milk lactoferrin concentration triggered by once daily milking is thought to be due to the induction and expression of the 20 lactoferrin gene.

The inventors have now discovered that milk lactoferrin concentration may be used as a pre-indicator of production change when altering the milking frequency of animals.

The inventors have found that animals with lower levels of lactoferrin in milk during standard twice-daily milking were shown to lose less milk yield per day when changed 25 to once daily milking than cows with higher levels of milk lactoferrin.

Our Ref: 120626/28 6 The relationship between milk lactoferrin concentration and daily milk yield can be used as a reference to determine the amount of production change likely when altering the milking frequency of animals.

Cows can be ranked according to comparative levels of milk lactoferrin present at the 5 same stage of lactation. It is anticipated that a skilled addressee could easily gather absolute values of lactoferrin concentration in milk for a given period of lactation by conducting a series of tests on milk samples.

This relationship can be used to determine the optimal milking strategies for different animals. For instance, cows with lower levels of milk lactoferrin during standard twice 10 daily milking could be milked once daily with minimal losses in daily milk yield. Animals with medium levels of lactoferrin could remain on a twice daily milking regime.

The relationship between lactoferrin and daily milk yield also indicates that cows with higher levels of lactoferrin in their milk during standard twice daily milkings could 15 potentially produce higher milk yields when milked three or more times daily. Whilst farm strategies in New Zealand are not presently ideal for milking three or more times daily, this is commonplace in Europe and the United States.

Lactoferrin levels in milk are known to vary with the stage of lactation of the cow, being high in early lactation, low through mid lactation and again increasing to 20 relatively high levels during late lactation.

However, the relative ranking of cows will likely remain substantially unchanged through lactation. Cows with comparatively high milk lactoferrin in early lactation would be expected to have comparatively high milk lactoferrin levels in late lactation, and vice versa.

In preferred embodiments, the level of milk lactoferrin from a previous year's lactation Our Ref: 120626/28 7 can be used to determine the optional daily milking strategy of animals for the following milking season.

Such farm management practices would allow dairy herds to be optimised for the desired milking frequency.

The inventors have identified lactoferrin as one milk component that can be used as indicators for determining the ideal daily milking frequency for maximum milk yield.

It has previously been shown that lactoferrin gene expression increases within 24 hours of involution, wherein changes in milk composition are similar to that observed during once-daily milking.

As such, it is likely that a number of other genes involved in mammary involution could also be used as pre-indicators for milking efficiencies and be used in the present invention.

In this regard, Serum Amyloid protein and Lipopolysaccharide Binding Protein are also milk components which could also likely be used.

The ability to predict the optimal daily milking frequency for maximal milk yield using cost-effective farming practices has a number of advantages.

The major advantage of once daily milking is the considerable time and labour saving for the farmer by not having to milk animals twice daily. There is also a considerable saving in associated shed costs, equipment and so forth.

Further, herds do not need to be brought in from the pasture as frequently, allowing more grazing time for the animals.

Previously, once daily milking has been characterised by reductions in daily milk yield and the accelerated regression of the udder, leading to further declines in daily milk yield as lactation progressed. The ability to predict which animals are likely to remain Our Ref: 120626/28 8 relatively unaffected by a change to once daily milking means daily milk yields throughout lactation can be substantially maintained whilst saving on both labour and resources.

Herds milked once daily may also be able to out produce herds milked twice daily by 5 increasing the animal stocking rate to compensate for any production loss. The increased stocking rate and savings in both time and labour would thus offset any small loss in daily milk yield from switching to once daily milking.

As countries have differing economic conditions and farm management practices, different levels of production loss may be cost effective, being varyingly offset by 10 savings in labour costs or commodity subsidies.

The present invention will also have important implications for genetic selection of animals, allowing the selection of bulls and/or dams whose daughters have been shown to produce milk of a certain lactoferrin content.

BRIEF DESCRIPTION OF DRAWINGS Further aspects of the present invention will become apparent from the following description which is given by way of example only and with reference to the accompanying drawings in which: Figure 1 shows the correlation between milk lactoferrin concentration and daily milk yield loss in cows changed from twice daily to once daily milking; 20 and Figure 2 shows the correlation between milk lactoferrin concentration and daily milk yield loss in cows changed from twice daily to once daily milking according to a second embodiment of the present invention; Our Ref: 120626/28 9 BEST MODES FOR CARRYING OUT THE INVENTION With reference to the Figures, there is described two studies showing the correlation between milk lactoferrin concentration and daily milk yield.

Example 1.

Eight cows (mixed breeds) in mid-lactation, grazing rye-grass/white clover pasture at Ruakura were used in this study. Animals were milked twice daily (TAD) from parturition and underwent a period of three days of once daily milking (OAD) beginning at day 123+4 of lactation, on average. Mean milk somatic cell count (SCC) before treatment was 178+53 x 103 cells/ml.

Milk samples were taken before, during and after OAD and assayed for lactoferrin using an ELISA method (Bethyl Laboratories, Montgomery, Texas, USA.) Daily milk yield and composition were also recorded.

Lactoferrin levels during twice daily milking and the extent of production loss in cows changed to once a day milking is shown in Table 1.

TAD Lactoferrin (ng/mi) Decrease in daily milk yield (kg) 243 0.6 129 1.7 164 1.4 306 2.4 110 0.7 137 -0.2 342 3.9 65 1.0 Table 1: Correlation between TAD milk lactoferrin concentration and decrease in daily milk yield on OAD milking.

The correlation between milk lactoferrin concentration prior to OAD milking and the losses in daily milk yield noted after three days of OAD milking is shown in Figure 1.

Our Ref: 120626/28 Cows with low levels of milk lactoferrin during twice-daily milking were shown to exhibit less daily production loss when changed to OAD milking than those animals with high pre-levels of milk lactoferrin.

As such, the inventors are able to use lactoferrin as a pre-indicator of daily production 5 loss when altering the milking frequency of animals.

Example 2.

To confirm the correlation shown by Example 1, a larger trial was undertaken by the inventors.

Milk lactoferrin and daily milk yield were measured in 32 cows of mixed age and breed 10 for 10 consecutive days on twice daily milking (TDM). The cows were then milked once daily (ODM) for 7 days and the daily milk yield loss determined.

The full regression model of this data using log TDM lactoferrin, % Friesian, log TDM SCC, log ODM SCC and age group accounts for 58% of the variation in daily milk yield loss with a residual standard deviation of 0.035. These parameters were 15 included in the model to account for their influence on lactoferrin concentration and daily milk yield loss.

The model estimates that a ten fold difference in TDM lactoferrin (e.g. 30 to 300 Mg/ml, or log TDM lactoferrin increasing by 1) is associated with a 4.6% ± 2.2% drop in daily milk yield on ODM as a percentage of TDM.

Figure 2 shows the relationship between the actual daily milk yield loss against that predicted using the model.

Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.

Our Ref: 120626/28 11

Claims (19)

CLAIMS:

1. A method for determining the extent of production change of an animal prior to altering milking frequency, characterised by the steps of a) collecting milk from the animal, b) assaying the milk to determine the level of a given milk component present, and c) comparing the milk component levels to reference levels indicative of production from animals milked at particular frequencies.

2. A method as claimed in claim 1 wherein the method is used to determine the optimal daily milking frequency of an animal for any given production variable.

3. A method as claimed in claim 1 or claim 2 wherein the method is used to determine the extent of production change in animals prior to changing from a twice daily milking schedule to a once daily milking schedule.

4. A method as claimed in any one of claims 1 to 3 wherein the production change is daily milk yield.

5. A method as claimed in any one of claims 1 to 4 wherein the animal is a cow.

6. A method as claimed in any one of claims 1 to 5 wherein the milk component is selected from the list of enzymes, proteins, hormones, cells, ions and nucleic acids.

7. A method as claimed in any one of claims 1 to 6 wherein the milk component is an indicator of the level of lactoferrin present. Our Ref: 120626/28 12 Intellectual Property Office of N.Z. 2 1 DEC 2004 d c r. c i \/ p n

8. A method as claimed in any one of claims 1 to 6 wherein the milk component is lactoferrin protein.

9. A method as claimed in any one of claims 1 to 6 wherein the milk component is serum amyloid protein.

10. A method as claimed in any one of claims 1 to 6 wherein the milk component is lipopolysaccharide binding protein.

11. A method as claimed in any one of claims 1 to 8 wherein the assay determines the concentration of lactoferrin in milk.

12. A method as claimed in any one of claims 1 to 11 wherein the level of milk component present is used a pre-indicator of production change prior to altering the milking frequency of an animal.

13. A method as claimed in claim 12 wherein animals are grouped according to comparative levels of milk component present at the same stage of lactation.

14 A method as claimed in claim 13 wherein the relative grouping of cows remains substantially unchanged through lactation.

15. A method as claimed in any one of claims 1 to 14 wherein the level of milk component present from a previous year's lactation can be used to determine the optional daily milking strategy of an animal for the following milking season.

16. A method as claimed in any one of claims 1 to 15 for the selection of bulls and/or dams whose daughters have been shown to produce milk with a given level of milk component.

17. The use of a commercially available assay selected for a given milk component and reference data of milk component levels indicative of Our Ref: 120626/28 13 production from animals milked at particular frequencies in the manufacture of a kit for determining the extent of production change of an animal prior to altering milking frequency via the method of any one of claims 1-16.

18. A method substantially as described herein, with reference to and as illustrated by the accompanying description and drawings.

19. A kit when used for determining the extent of production change of an animal milked at a particular frequency substantially as described herein, with reference to and as illustrated by the accompanying description and drawings. AgResearch Limited by its Attorneys JAMES & WELLS Our Ref: 120626/28 14 Intellectual Property Office of N.Z. 2 t DEC 2004 RECEIVED