Effects of feeding complexed zinc, manganese, copper, and cobalt to late gestation and lactating dairy cows and claw integrity, reproduction, and lactation performance

Professional Animal Scientist, Sep 2002 by Ballantine, H T, Socha, M T, Tomlinson, D J, Johnson, A B, Et al

Abstract

Three hundred multiparous Holstein cows (150 cows per treatment) were blocked according to calving date and randomly assigned to a study to determine the effect of trace mineral source on incidence and severity of claw lesions, reproduction, and lactation performance of dairy cattle. Treatments were 1) all trace minerals supplied by sulfates (ITM) or 2) 360 mg Zn from Zn amino acid complex, 200 mg Mn from Mn amino acid complex, 125 mg Cu from Cu amino acid complex, and 12 mg Co from Co glucoheptonate per day (CTM; Availa(R); Zinpro Corporation, Eden Prairie, MN) replacing an equivalent amount of Zn, Mn, Cu, and Co from sul fates. Cows

received assigned treatments from 21 d prior to calving through 250 d of lactation. Cows fed CTM produced 1.2 kg more (P

(Key Words: Availa(R)-4, Lactation, Reproduction, Claw, Trace Minerals.)

Introduction

Zinc, Mn, Cu, and Co have important roles in maintaining fertility and claw integrity of dairy cattle (11, 13, 18). They are involved in protein synthesis, vitamin metabolism, formation of connective tissue, and immune function. Availability of trace minerals is affected by factors such as dietary levels of Fe, S, Ca, and heavy metals (13). Research has demonstrated that Zn Met (ZM) is more bioavailable to young growing chicks than inorganic sources, and the difference in bioavailability between these sources increases as the level of antagonists in the diet increases (24). Research has also demonstrated that Cu Lys tended to be retained better by calves than Cu sulfate and that this difference in retention between sources increases following a period of induced stress (15).

Cattle fed ZM have demonstrated reduced somatic cell counts (SCC) (9), increased milk production (9, 19), and improved claw integrity (2, 12). Further improvements in milk production and claw integrity as well as improvements in reproduction have been observed when Co glucoheptonate and specific amino acid complexes of Mn and Cu were added to diets of cows already containing ZM (14, 22).

Recently, metal amino acid complexes have been introduced to the market. Similar to metal-specific amino acid complexes, metal amino acid complexes have one metal attached to one amino acid. In contrast to metal-specific amino acid complexes, the amino acid that is attached to the metal is not specified. The objective of this study is to determine the effects of replacing sulfate forms of Zn, Mn, Cu, and Co with amino acid complexes of Zn, Mn, and Cu and Co glucoheptonate on lactation, fertility, and claw integrity of late gestation and early lactation dairy cattle.

Materials and Methods

Three weeks prior to calving, 300 multiparous Holstein cows were randomly assigned to a study to determine the effects of trace mineral source on incidence and severity of claw lesions, reproduction, and lactation performance. Treatments were 1) a diet with all trace minerals supplied by sulfates (ITM) or 2) a diet in which 360 mg Zn from Zn amino acid complex, 200 mg Mn from Mn amino acid complex, 125 mg Cu from Cu amino acid complex, and 12 mg Co from Co glucoheptonate per day (CTM; Availa(R)-4) replaced an equivalent amount of Zn, Mn, Cu, and Co from sulfates. Cows received their treatment diets from 21 d prior to calving through 250 d of lactation. Treatments were blended into a supplement at a commercial feed mill and delivered to the dairy. Supplements were similar in ingredient and chemical composition, differing only in source of Zn, Cu, Mn, and Co (Table 1). Two supplement formulations were used: one fed during the prefresh period, and the other during the lactation period. Supplements were blended into a total mixed ration (TMR) (Table 2) and group-fed three times daily at a rate to achieve 5 to 10% orts.

Cows were housed in a naturally ventilated barn with sand-bedded free stalls in early lactation and then moved to outside lots in mid lactation. Cow movement was controlled to maintain an equal number of control and treatment cows in both the free-stall barn and the outside lots.

Cows were milked three times daily, and milk weights were recorded at each milking. Milk was sampled twice monthly and analyzed for milk components and SCC (Florida DHI, Gainesville, FL). Administration of recombinant bovine somatotropin (rbST) (Posilac(R); Protiva, Inc., St. Louis, MO) began during wk 9 of lactation with re-injection occurring every 14 d thereafter.

Trace mineral status of cows was assessed by collecting liver biopsies from 32 animals per treatment. Biopsies were collected prior to initiation of treatments and at approximately 18 wk postcalving. Samples were sent to the Michigan State Animal Health Diagnostic Laboratory (Lansing, MI) for mineral analysis.

Claws were trimmed prior to initiation of treatments and at approximately 75 and 250 d postcalving by two claw trimmers. The claw trimmers were graduates of the Master Hoof Program (University of Florida, Gainesville, FL) and were not informed of the cows' treatment assignment. Furthermore, each trimmer examined an equal number of control and treatment cows. Lesions were noted in the seven zones of the claw [adapted from (6)], and each lesion was scored for severity on a three-point scale (1 = no pain, 2 = moderate pain, and 3 severe pain). For cows exhibiting a noted claw disorder, a claw lesion index was calculated by taking the number of zones affected and multiplying it by the average severity score of the lesions. Data collected prior to treatment assignment were used as a covariate to adjust data collected postcalving.