Chelated minerals help lameness, infertility in cows

Chelated minerals help lameness, infertility in cows

Supplying dairy cows with sufficient trace minerals like copper, manganese and zinc can help reduce lameness and improve reproduction.

By HEATHER TUCKER*

*Dr. Heather Tucker is a research scientist, ruminant nutrition, with Novus International.

INFERTILITY and lameness are critical challenges that dairy producers and veterinarians must deal with on a daily basis.

Both issues can result in serious economic losses for producers due to decreased milk yield, reduced fertility and increased treatment costs and culling rates. Proper management — of both the facility and nutrition — plays a role in reducing the incidence of infertility and lameness.

Supplying sufficient trace minerals like copper, manganese and zinc can be part of the solution to reducing lameness and improving reproduction.

Even though trace minerals are fed to dairy cows at low level, they are essential for the cow's health and performance, including hoof integrity, fertility, milk production and immune function. Trace minerals such as copper, manganese and zinc play important roles in protein synthesis, vitamin metabolism, formation of connective tissue and immune function. They have typically been offered to cattle as inorganic compounds in the form of salts, such as oxides, chlorides, sulfates and carbonates.

With these inorganic salts, the trace mineral dissociates in the digestive tract, allowing the free minerals to interact with feed to form insoluble or indigestible compounds.

As milk production per cow has progressively increased, there has been a heightened interest in the use of organic trace minerals in rations for dairy cows. Organic forms of copper, manganese and zinc — including metal amino acid chelates, metal complexes, metal methionine hydroxyl analog chelates, metal proteinates and metal propionates — have been shown to increase intestinal absorption and mineral bioavailability.

Thus, organic forms of trace minerals could be supplied at a lower inclusion rate but still provide the same amount of available mineral as inorganic forms; alternatively, feeding similar levels of organic supplements in place of inorganic forms may result in an increased bioavailable supply of trace minerals to the animal.

 

Chelated trace mineral study

In a recent study, dairy cows were fed a ration in which inorganic trace minerals (ITMs) were partially replaced with chelated trace minerals (CTMs) — with zinc, copper and manganese supplied as MINTREX chelated trace minerals — or a ration containing only ITMs — supplied as sulfates, carbonates and oxides at a commercial level. The objective of the study was to evaluate how the rations affected the locomotion score, milk production and reproductive performance of dairy cows in different herds.

Twenty-seven dairy herds belonging to a dairy cooperative in central Spain that fed the same total mixed ration (TMR) were enrolled in the six-month study. Over the duration of the trial, the total number of lactating cows enrolled in the study was 2,880.

Fifteen herds continued to receive the same TMR containing ITMs, and the remaining 12 herds were fed a similar TMR, with the only difference being a partial replacement of ITMs with CTMs.

The ITM premix provided 57 parts per million of inorganic zinc, 9 ppm of inorganic copper and 27 ppm of inorganic manganese, whereas the CTM premix contained 32 ppm of inorganic zinc plus 25 ppm of chelated zinc, 3 ppm of inorganic copper plus 6 ppm of chelated copper and 17 ppm of inorganic manganese plus 10 ppm of chelated manganese. The first month of the study was used as a covariate period, and in the following five months, herds were exposed to the dietary treatments.

The results showed that there were no differences in feed offered or milk production due to treatment. Although the overall proportion of cows with a lameness score greater than three (considered to be lame) did not differ between ITM and CTM herds, there was a significant interaction between treatment and the month of the study. This was due to a numerically greater prevalence of lameness in CTM herds than in ITM herds during the first two months of the study and a lesser prevalence in the last three months of the study (Figure).

Cows in ITM herds had more than two times greater risk of being culled due to lameness. A partial replacement of inorganic for chelated forms of copper, manganese and zinc improved the overall lameness incidence.

Cows that had received the CTMs for at least 30 days prior to the first artificial insemination had a 30% improvement in conception rate and were 1.5 times more likely to become pregnant than those receiving only ITMs (Table). At second insemination, there was a trend for greater odds of conception for cows fed the CTM diet.

In conclusion, replacing ITMs with CTMs can help reduce lameness and improve conception rates in dairy cows compared to feeding only ITMs.

Chelated minerals help lameness, infertility in cows

Reproductive performance, as affected by treatments and time of exposure to treatments

 

-Treatment-

Std.

-P-value-

Item

ITM

CTM

error

Treatment

Month

TxtM*

Conception rate at first service, %

 

 

 

 

 

 

All cows

29.4

36.6

Odds ratio (95% CI**)

 

1.20 (0.16-1.49)

 

0.14

<0.001

<0.001

Cows >30 days on treatment

26.8

35.9

Odds ratio (95% CI)

 

1.53 (1.08-3.11)

 

0.003

0.47

<0.001

*Interaction between treatment and month.

**Confidence interval.

 

Volume:88 Issue:12

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