PBG06 Cattle grazing and cattle performance in the Patch-Burn Grazing experiment at Konza Prairie

Abstract:

PBG datasets are associated with a long-term, large-scale study that is addressing the effects of fire-grazing interactions in the context of a Patch-Burn Grazing management system designed to promote grassland heterogeneity. Effects of patch-burn grazing management on plant and animal diversity and the nature and variety of wildlife habitat are being assessed in two replicate management units, each consisting of three pastures (watersheds) designated C03A/C03B/C03C and C3SA/C3SB/C3SC. In each patch-burn grazing unit, one watershed is burned and two that are left unburned in a given year. The burning treatments are rotated annually so that each pasture is burned every third year. Each patch-burn grazing unit is paired with an annually-burned pasture for comparison with traditional grazing systems (C01A and C1SB). All grazing units are stocked with cow/calf pairs from approximately 1 May until 1 Oct at a stocking density equal to 3.2 ha per cow/calf. To examine the impact of patch burning and grazing in all 8 units, we monitor changes in plant species composition, residual biomass, grassland bird populations, insect populations, small mammal populations, soil nutrients, and stream water quality¹ (¹C3SA/C3SB/C3SC unit only). The KSU Department of Animal Science monitors cattle performance, including weight gain and body condition to assess the economic feasibility of using patch-burn management on a widespread basis.

This data set focuses on monitoring (1) the dynamics of cattle grazing on each of two sets of three pastures burned each year on a rotating basis and (2) cattle performance including cow weight gain, body condition, and reproductive performance and calf weight gains.

Data set ID:

120

Core Areas:

Short name:

PBG06

Purpose:

Long-term monitoring of dynamics of cattle grazing on each of two sets of three pastures burned each year on a rotating basis and cattle performance including cow weight gain, body condition, reproductive performance and calf weight gains.

Methods:

Location of Sampling Stations: The study is comprised of two units on Konza Prairie that line the west side of Kansas Highway 177. The south unit (watersheds C3A, C3B, and C3C) consists of 452 acres and is stocked with 56 cow calf pairs, with 27 pairs on the smaller adjacent control plot (watershed C1A). The replicating north unit (watersheds C3SA, C3SB and C3SC) is stocked with a comparable 103 pairs on 829 acres with 19 pairs on the adjacent control plot (watershed C1SB).

Each unit has been divided into three sections. Cattle will be allowed to roam the entire unit. But only one-third of the unit will be burned each year on a rotating basis. See 'Burn History' on the Konza LTER web site.

Frequency of Sampling: Cattle will be weighed and assigned a body condition score on or about May 1, July 15, and October 1 of each grazing season. Reproductive success will be assessed on or about July 15 and October 1 of each grazing season.

Variable Measured: Weights and condition of cows and calves. Reproductive performance of cows.

Methods: Cow body-weight (BW) and body-condition-score (BCS) measurements are obtained on the day individual cows calve, at the time of fixed-time artificial insemination (AI), and at weaning. At each time point, cow BCS is assigned (1 to 9 scale; 1 = emaciated, 9 = morbidly obese) by 3 trained observers that are blinded to treatment; the average of 3 scores is recorded. Calf BW 1s recorded at birth, at the time of fixed-time AI, and at weaning.

Ovulation is synchronized using a 5-day CO-Synch + controlled-intervaginal-drug-release (CIDR) protocol (Figure 1) and cows are inseminated 72 hours after CIDR removal. Cows are exposed to fertile bulls for natural-service breeding beginning 10 days after fixed-time AI for 50 days. Conception to fixed-time AI is determined via ultrasound 33 to 35 days after AI and final pregnancy rate was determined via rectal palpation approximately 120 days after AI. Subsequent calving dates are recorded in order to establish distribution over a 60-day calving season.