Effects of Lutrell® Combi in a large-scale trial of transit cows to test milk output, fertility and general health
 

Conjugated linoleic acid (CLA) is a form of linoleic acid that occurs naturally in the milk and meat (or fat) of ruminants. Numerous tests have confirmed that CLA, when administered to cows in rumen-protected form, is a very effective way of reducing the milk fat content. When there are low pH values in the rumen, the rumen’s microorganisms also make CLA from multiply unsaturated fatty acids. This explains the low milk fat content in cases of rumen acidosis. The reduction of the milk fat content takes the strain off the lipid metabolism and is generally associated with an improved energy level, which can probably be assumed to have positive effects on the animal’s fertility. It has only been possible to demonstrate these effects in studies involving large numbers of animals, or alternatively by using special statistical methods based on the results of numerous smaller studies. Both approaches have now been tried, with a large-scale trial using 450 animals in three groups, and a statistical analysis (or meta-analysis) of 5 published smaller studies (De Veth et al., 2009).

Material and methods
450 freshly lactating cows were divided into three groups shortly before reaching the calving date. A control group was given a standard TMR diet; one of the test groups was given Lutrell Combi from 15 days before calving up to 25 days after calving; the third group continued to receive Lutrell Combi for a further period up to the 65th day after calving. The TMR feed included rumen-protected fat. The daily dosage of Lutrell Combi was 150 g per animal. The quantity of milk was measured daily. The main fertility parameters were also registered: inseminations per animal, days open and the mortality rate. The period over which the daily milk output was measured came to over 200 days.

1. Results: milk output and fertility
The Lutrell Combi cows achieved a milk output level that was significantly higher (a difference of ca. 4 kg) than that of the control group (see Diagram 1).

Diagram 1: Milk output in the first 200 days with Lutrell Combi

 
Positive results were also reported in relation to fertility (see Diagram 2). 50% of the animals of the control group were pregnant only after 171 days had elapsed, whereas in the Lutrell groups this quota was achieved after just 140 days and 115 days respectively. This means that Lutrell Combi succeeded in reducing the days open by 57 or 31 days. On conclusion of the fertility observations (ca. 350 days), almost 90% of the cows were pregnant in the Lutrell groups as against only 74% of the control groups.

Diagram 2: When had 50% of the cows become pregnant?

 
2. Results: wellbeing
Poor fertility is associated with numerous symptoms of sickness, above all in the time around calving. These not infrequently lead to the early death of the animal. Subclinical ketosis, fatty liver, prostration, dislocation of the abomasum, lameness, afterbirth retention, cysts on the corpus luteum and ovaries and immunodepression are among the conditions deserving mention in this connection. The latter makes it more likely that the cows will succumb to mastitis, metritis and other serious infections. In particular, unspecific cases of death and mastitis immediately following calving are common causes of premature death. Infertility on the other hand only becomes a reason for eliminating the animal from the herd after an extended period. Naturally attempts will be made first, with the help of modern gynaecological methods, to enable the cows to become pregnant once more.

Diagram 3: Time of elimination of dairy cows with reasons

 
2200 herds were studied.
Unspecific cases of death increase between 3 weeks before and 10 weeks after calving.
In the same period injuries also occur more frequently.
Mastits occurs with greater frequency in the first half of the lactation period.
The trial described above also followed up whether and when animals had to be eliminated (i.e. culled) from the herd. The reasons for this were essentially in agreement with those reported from the USA above and illustrated in the Dechow and Goodling diagram. Diagram 7 not only shows that twice as many animals in the control group dropped out as in the two Lutrell Combi groups, it also reveals that in the first 60 days none of the Lutrell groups lost any animals at all.

Diagram 4: Losses during lactation

 
Conclusion
Lutrell Combi, administered during the transit phase (2 to 3 weeks ante partum up to 4 to 7 weeks post partum) helps dairy cows to overcome the stress associated with a negative energy balance and the mobilisation of body fat. Lutrell Combi results in a higher milk output, together with improved fertility and a better general state of wellbeing. These factors together result in an economic potential which in the large-scale trial for example increased the net profit by as much as € 300 per cow per annum.

Dechow, C.D. and R.C. Goodling. 2008. Mortality, culling by sixty days in milk and production profiles in high- and low- survival Pennsylvania herds. J. Dairy Sci. 91:4630-4639.

De Veth, M.J., D.E. Bauman, W. Koch, G.E. Mann, A.M. Pfeiffer, and W.R. Butler 2009: Efficacy of conjugated linoleic acid for improving reproduction: A multi-study analysis in early-lactation dairy cows. J. Dairy Sci. 92:2662-2669