Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: physiological and productive response of cows and their offspring until weaning

Abstract

One hundred and ninety non-lactating, pregnant beef cows (¾ Bos taurus and ¼ Bos indicus; 138 multiparous and 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (d 0). Cows were ranked by parity, pregnancy type (artificial insemination = 102, natural service = 88), body weight (BW) and body condition score (BCS), and assigned to receive a supplement containing: 1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 95) or 2) an organic complexed source of Cu, Mn, Co, and Zn (AAC; Availa®4; Zinpro Corporation, Eden Prairie, MN; n = 95). The INR and AAC provided the same daily amount of Cu, Co, Mn, and Zn, based on 7 g of the AAC source. From d 0 to calving, cows were maintained in a single pasture and were segregated three times weekly into 1 of 24 individual feeding pens to receive treatments. Cow BW and BCS were recorded on d -30, d 97, upon calving, and at weaning (d 367). Milk production was estimated at 42 ± 0.5 d postpartum via weigh-suckle-weigh (WSW). Liver biopsies were performed in 30 cows/treatment on d -30, 97, upon calving, and the day after WSW. Calf BW was recorded at birth and weaning. Liver and longissimus muscle (LM) biopsies were performed in 30 calves/treatment upon calving and 24 h later, the day after WSW, and at weaning. No treatment effects were detected (P ≥ 0.49) for cow BCS during gestation, despite AAC cows having greater (P = 0.04) BW on d 97. Liver Co concentrations were greater (P < 0.01) for AAC compared to INR cows, and liver concentrations of Cu were greater (P = 0.02) for INR compared to AAC cows on d 97. Upon calving, INR cows had greater (P ≤ 0.01) liver Cu and Zn concentrations compared to AAC cows. No other treatment differences were noted (P ≥ 0.17) for cow and calf liver trace mineral concentrations. Cows receiving AAC had greater (P = 0.04) hepatic mRNA expression of metallothionein 1A at calving, and their calves had greater (P = 0.04) hepatic mRNA expression of superoxide dismutase at weaning. Milk production did not differ between AAC and INR cows (P = 0.70). No treatment effects were detected (P ≥ 0.29) for mRNA expression of LM genes associated with adipogenic or muscle development activities in calves at birth and weaning. Calf birth and weaning BW also did not differ (P ≥ 0.19) between treatments. In summary, supplementing Co, Cu, Zn, and Mn as organic complexed or sulfate sources to beef cows during the last 5 mo of gestation yielded similar cow-calf productive responses until weaning.

Supplementing organic-complexed or inorganic Co, Cu, Mn, and Zn to beef cows during gestation: postweaning responses of offspring reared as replacement heifers or feeder cattle

“…This manuscript describes the postweaning responses of the female and male offspring reared, respectively, as replacement heifers and feeder steers for slaughter. A companion manuscript ( Harvey et al, 2021 ) describes pre- and postpartum responses of cows, as well as offspring responses from birth through weaning.…”

“…A full description of dietary treatments and management scheme applied to beef cows are described in the companion manuscript ( Harvey et al, 2021 ). Briefly, 190 nonlactating, pregnant beef cows (average ¾ Bos taurus and ¼ Bos indicus ; 138 multiparous, 52 primiparous) were assigned to this experiment at 117 ± 2.2 d of gestation (day 0 of the experiment).…”

“…Growth rate of each heifer was also modeled by linear regression of BW against sampling days (days 437 to 619), and each regression coefficient was used as individual response. On day 584, 15 heifers from each treatment were randomly selected for liver and longissimus muscle ( LM ) biopsy as described in the companion manuscript ( Harvey et al, 2021 ). Heifers were observed daily for BRD signs from days 437 to 620 according to Berry et al (2004) .…”

“…Steers were observed daily for BRD signs from days 437 to 493 according to Berry et al (2004) , and according to the DART system (Zoetis) from day 493 until slaughter based on the management criteria of the feedyard. On day 586, 15 steers from each treatment were randomly selected for liver and LM biopsies ( Harvey et al, 2021 ). At the commercial packing plant, hot carcass weight ( HCW ) was collected upon slaughter.…”

“…All feed samples were analyzed for concentrations of crude protein, acid detergent fiber, neutral detergent fiber, macro-, and trace minerals as described in the companion manuscript ( Harvey et al, 2021 ). Calculations for total digestible nutrients used the equation proposed by Weiss et al (1992) , and calculations for net energy for maintenance and gain used the equations proposed by NRC (2000) .…”