Morris St

Agricultural Science in the Wild: A Social Network Analysis of Farmer Knowledge Exchange

Responding to demands for transformed farming practices requires new forms of knowledge. Given their scale and complexity, agricultural problems can no longer be solved by linear transfers in which technology developed by specialists passes to farmers by way of extension intermediaries. Recent research on alternative approaches has focused on the innovation systems formed by interactions between heterogeneous actors. Rather than linear transfer, systems theory highlights network facilitation as a specialized function. This paper contributes to our understanding of such facilitation by investigating the networks in which farmers discuss science. We report findings based on the study of a pastoral farming experiment collaboratively undertaken by a group of 17 farmers and five scientists. Analysis of prior contact and alter sharing between the group’s members indicates strongly tied and decentralized networks. Farmer knowledge exchanges about the experiment have been investigated using a mix of quantitative and qualitative methods. Network surveys identified who the farmers contacted for knowledge before the study began and who they had talked to about the experiment by 18 months later. Open-ended interviews collected farmer statements about their most valuable contacts and these statements have been thematically analysed. The network analysis shows that farmers talked about the experiment with 192 people, most of whom were fellow farmers. Farmers with densely tied and occupationally homogeneous contacts grew their networks more than did farmers with contacts that are loosely tied and diverse. Thematic analysis reveals three general principles: farmers value knowledge delivered by persons rather than roles, privilege farming experience, and develop knowledge with empiricist rather than rationalist techniques. Taken together, these findings suggest that farmers deliberate about science in intensive and durable networks that have significant implications for theorizing agricultural innovation. The paper thus concludes by considering the findings’ significance for current efforts to rethink agricultural extension.

The bone-muscle ratio of fetal lambs is affected more by maternal nutrition during pregnancy than by maternal size

Bone formation and loss are related to the strain imposed on bone by muscle forces. Bone mineral content (BMC) and lean mass (LM) of fetal lambs was determined at day 140 of pregnancy in 8 groups of ewes, which were of either large or small body size, on either high (ad libitum) or maintenance pasture intake from day 21 of pregnancy, or carrying either singletons or twins. BMC and LM (using DXA scanning) of fetal hindquarters/spine were corrected to leg length. BMC and LM were less in twin than singleton groups (P < 0.001). Large ewes on high intake produced single fetuses with a (group mean) BMC/LM ratio that was higher (P < 0.002) than that in fetuses of large ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. In single fetuses from small ewes on high intake, the BMC/LM ratio was higher than those from small ewes with singletons on maintenance intake or twins on either high or maintenance intakes, the ratios of which were not different. The ratio was not different in singleton fetuses of ewes on high intake, whether they were large or small. Different fetal environments resulted in a given amount of muscle being associated with a higher or lower bone mass. Dietary intake during pregnancy was more important than maternal size in affecting the ratio. We conclude that intrauterine environmental factors may be important in determining bone mass postnatally, and possibly later in life.

Does offering concentrate supplement during late pregnancy affect twin- and triplet-bearing ewe and lamb performance?

Abstract This study investigated the effect of offering concentrate supplement during late pregnancy on twin- and triplet-bearing ewe and lamb performance. Twin- (n=40) and triplet-bearing (n=20) ewes were grazed on a 6 cm herbage height from day 70 of pregnancy until parturition. From pregnancy day 102, half of the ewes from each litter size were offered 400 g/ewe per day of concentrate sheep pellets. From day 102 until day 145 of pregnancy, ewes offered concentrate gained 60 g more liveweight per day than ewes offered pasture only (P<0.01). Ewes offered concentrate were also under less metabolic stress in late pregnancy, as indicated by lower (P<0.05) plasma beta-hydroxybutyrate (BOH) and non-esterified fatty acid (NEFA) concentrations. Offering concentrate increased lamb birth weight from 3.9 to 4.2 kg (P<0.05) and tended to increase lamb plasma gamma-glutamyl-transferase (GGT) concentrations at age 24–36 h (P = 0.08). It had no effect, however, on lamb plasma glucose or immuno-globulin G (IgG) concentrations within 24–36 h of age, lamb growth from birth until day 52 of lactation or lamb survival. Ewes offered concentrate reared a greater total weight of lamb to day 52 of lactation than ewes offered pasture only. The economic viability of offering a concentrate to these ewes grazing a 6 cm sward could not be established.

The performance of single-rearing ewes and their lambs offered ryegrass pasture or herb–clover mix during lactation

ABSTRACT Lamb growth to weaning has important implications for the profitability of farms producing lambs for meat. Alternative forage crops such as chicory, plantain, red clover and white clover have the potential to increase lamb growth rates to weaning percentage sold to slaughter at weaning. A study was conducted over two years to examine the growth of single-born lambs offered either pasture or herb-mix (chicory, plantain, white clover and red clover) from birth to weaning. Each year, 80 single-bearing ewes were allocated to either a pasture or herb-clover mix. In 2014, ewes and lambs that were offered the herb-clover mix had greater live weights at weaning than those grazed on ryegrass pasture. In 2015, however, no differences in lamb weaning weight was observed. In both years of the study, lambs reared on the herb clover mix had growth rates in excess of 400 g/day, from birth to weaning.

The potential interaction between ewe body condition score and nutrition during very late pregnancy and lactation on the performance of twin-bearing ewes and their lambs

Objective The present study aimed to determine the impact of ewe body condition score (BCS) (over a range of 2.0 to 3.0) and nutritional treatments (consisting of differing herbage masses) during very late pregnancy and lactation and their potential interaction on the performance of twin-bearing ewes and their lambs to weaning. Methods On day 142 of pregnancy, twin-bearing ewes with a BCS of 2.0, 2.5, or 3.0 were allocated to a “Moderate’ or ‘Unrestricted’ nutritional treatment until day 95 of lactation (weaning). The nutritional treatments aimed to achieve average herbage masses of 1,200 to 1,300 kg dry matter (DM)/ha (Moderate) and 1,500 to 1,800 kg DM/ha (Unrestricted). Results There were no three-way interactions between ewe BCS group, nutritional treatment and time for any ewe or lamb parameter. The nutritional treatments had no effect (p>0.05) on lamb birth or weaning weight. Lambs born to Moderate ewes had greater survival and total litter weight at weaning (p<0.05). Regardless of BCS group, Unrestricted treatment ewes had greater body condition and back-fat depth at weaning than Moderate treatment ewes (p<0.05). Ewes of BCS 2.0 group reared lighter lambs to weaning (p<0.05) and tended to have a lower total litter weight (p = 0.06) than BCS 3.0 group ewes. Conclusion This study suggests farmers should aim to have all ewes with a BCS of 2.5 or 3 in late pregnancy for optimal lamb weaning performance. Furthermore, there is no benefit to lamb production of offering ewes pasture masses >1,200 kg DM/ha during very late pregnancy and lactation.

Estimation of herbage intake of Angus heifers from growth rate and milk production selection lines

Abstract Herbage intake was measured using n-alkanes (at age 10 and 13 months) and the pre- and post-grazing technique (at age 12 and 14 months) in 80 Angus heifers selected for high (Hi-Gr) or low (Lo-Gr) growth rate or high (Hi-Milk) or low (Lo-Milk) milk production. Average liveweight and estimated herbage intake at 10 months were 240.2±0.4 kg and 3.47±0.1 kg dry matter (DM)/head per day respectively. The respective values at 13 months of age were 287.2±1.9 kg and 6.50±0.36 kg DM/head per day. No differences in estimated herbage intake among the genetic lines were detected using n-alkanes at 10 or 13 months of age. Average liveweight at 12 months of age was 247.1±0.7 kg and mean estimated intakes were 4.86±0.26, 4.17±0.26, 4.37±0.26 and 3.00±0.26 kg DM/head per day for the Hi-Gr, Lo-Gr, Hi-Milk and Lo-Milk lines, respectively. The Lo-Milk line had lower (P<0.05) estimated intake than the other three lines. At 14 months of age, average liveweight was 272.5±0.6 kg and estimated intakes were 6.99±0.18, 6.52 kg±0.18, 6.71±0.18 and 7.28±0.19 kg DM/head per day for the Hi-Gr, Lo-Gr, Hi-Milk or Lo-Milk lines, respectively. Lo-Milk heifers had higher (P<0.05) intakes than heifers from the Lo-Gr and Hi-Milk lines. No statistical difference in intake between the Lo-Milk and the Hi-Gr lines was detected. In general, the Hi-Gr heifers outperformed the heifers from other lines.