Farming Systems: Beyond Production Technologies for Dairy RD&E

The challenge of Research, Development and Extension (R,D&E) is to apply agricultural science to serve the real needs of production systems. The ideal is to have community partnerships involving a variety of stakeholders with equal representation, and a sharing in the design of R, D&E actions. R,D&E policy in Australia is stressing the participation of industry in new projects. The Dairy Research and Development Corporation (DRDC) in Australia, and the Brazilian Agricultural Research Corporation for Dairy (Embrapa Dairy), have developed initiatives to identify priorities for R,D&E design with participation of the industry. However, weaknesses in the methods have been identified. The present study describes the results of a strategy to involve a broader range of stakeholders in the identification of regional dairy industry needs. The findings show that overall communication, finance and marketing as the three major priorities of three study regions, meaning that primary needs for the industry are not in production technologies. This is an apparent contradiction with what some stakeholders considered valuable for dairy farms, which are pasture, genetics and nutrition technologies. The results reflect the large amount of research activity into production technology, and the relative success of R,D&E. However, it is necessary to consider issues beyond production technologies before developing R,D&E projects or presenting technologies.

Growth hormone induces bone morphogenetic proteins and bone-related proteins in the developing rat periodontium

The hypothesis that growth hormone (GH) up-regulates the expression of enzymes, matrix proteins, and differentiation markers involved in mineralization of tooth and bone matrices was tested by the treatment of Lewis dwarf rats with GH over 5 days, The molar teeth and associated alveolar bone were processed for immunohistochemical demonstration of bone morphogenetic proteins 2 and 4 (BMP-2 and -4), bone morphogenetic protein type IA receptor (BMPR-IA), bone alkaline phosphatase (ALP), osteocalcin (OC), osteopontin (OPN), bone sialoprotein (BSP), and E11 protein (E11), The cementoblasts, osteoblasts, and periodontal ligament (PDL) cells responded to GH by expressing BMP-2 and -4, BMPR-IA, ALP, OC, and OPN and increasing the numbers of these cells. No changes were found in patterns of expression of the late differentiation markers BSP and E11 in response to GH, Thus, GH evokes expression of bone markers of early differentiation in cementoblasts, PDL cells, and osteoblasts of the periodontium. We propose that the induction of BMP-2 and -4 and their receptor by GH compliments the role of GH-induced insulin-like growth factor 1 (IGF-1) in promoting bone and tooth root formation.

Tissue-specific induction of SOCS gene expression by PRL

The mechanisms whereby tissue sensitivity to PRL is controlled are not well understood. Here we report that expression of mRNA and protein for members of the SOCS/CIS/JAB family of cytokine signaling inhibitors is increased by PRL administration in ovary and adrenal gland of the lactating rat deprived of circulating PRL and pups for 24 h but not in mammary gland. Moreover, suckling increases SOCS mRNA in the ovary but not in the mammary gland of pup-deprived rats. Deprivation of PRL and pups for 48 h allows the mammary gland to induce SOCS genes in response to PRL administration, and this is associated with a decrease in basal SOCS-3 mRNA and protein expression to the level seen in other tissues, suggesting that SOCS-3 induced refractoriness related to filling of the gland. In reporter assays, SOCS-1, SOCS-3, and CIS, but not SOCS-2, are able to inhibit transactivation of the STAT 5-responsive beta -lactoglobulin promoter in transient transfection assays. Moreover, suckling results in loss of ovarian and adrenal responsiveness to PRL administered 2 h after commencement of suckling, as determined by STAT 5 gel shift assay. Immunohistochemistry was used to localize the cellular sites of SOCS-3 and CIS protein expression in the ovary and adrenal gland. We propose that induced SOCS-1, SOCS-3, and CIS are actively involved in the cellular inhibitory feedback response to physiological PRL surges in the corpus luteum and adrenal cortex during lactation, but after pup withdrawal, the mammary gland is rendered unresponsive to PRL by increased levels of SOCS-3.

The effect of sodium chloride supplementation on the milk production of grazing Holstein Friesian cows during summer and autumn in a humid sub-tropical environment

Two studies were conducted to examine the effects of including NaCl at various rates in grain-based supplements for Friesian cows grazing established, dominant (>90%), rainfed kikuyu (Pennisetum clandestinum cv. Common) pastures during summer and autumn in a humid sub-tropical environment. In study 1 (19 January-27 March 1998), 48 cows (36 multiparous, 12 primiparous; 27-96 days postpartum) were allocated to one of four groups based on genetic merit, milk production, liveweight (LW) and days postpartum. They were fed (2.7 kg dry matter (DM) per cow, twice-a-day) one of four isoenergetic and isonitrogenous barley grain-based concentrates containing NaCl at concentrations (% as-fed) of either 0 (SC1), 1.1 (SC2), 2.2 (SC3) or 3.3 (SC4). Maximum temperature humidity index (THImax) was greater than or equal to78 during 50% of the experimental period. Concentrate NaCl content had no effect (P>0.05) on daily milk yield or LW change but daily yields of 4% fat corrected milk (FCM), fat and protein were higher (P0.05) among treatments at 7.6+/-1.24 kg DM per cow. In study 2 (18 January 1999-1 March 1999), 48 cows (32 pluriparous, 16 primiparous: 32-160 days postpartum) were fed (2.7 kg DM per cow twice-a-day) one of two isoenergetic and isonitrogenous barley grain-based concentrates containing NaCl at concentrations (% as-fed) of 0 (control) or 2.2 (HSC). THImax was greater than or equal to78 during 34% of days in the experimental period. Yields of milk, FCM, fat and protein were lower (P0.05) by concentrate NaCl content. These studies indicate that NaCl supplementation can be beneficial in terms of milk production during warm, humid conditions as opposed to milder conditions. (C) 2002 Elsevier Science B.V. All rights reserved.

Acute bovine laminitis: A new induction model using alimentary oligofructose overload

Twelve dairy heifers were used to examine the clinical response of an alimentary oligofructose overload. Six animals were divided into 3 subgroups, and each was given a bolus dose of 13, 17, or 21 g/kg of oligofructose orally. The control group (n = 6) was sham-treated with tap water. Signs of lameness, cardiovascular function, and gastrointestinal function were monitored every 6 h during development of rumen acidosis. The heifers were euthanized 48 and 72 h after administration of oligofructose. All animals given oligofructose developed depression, anorexia, and diarrhea 9 to 39 h after receiving oligofructose. By 33 to 45 h after treatment, the feces returned to normal consistency and the heifers began eating again. Animals given oligofructose developed transient fever, severe metabolic acidosis, and moderate dehydration, which were alleviated by supportive therapy. Four of 6 animals given oligofructose displayed clinical signs of laminitis starting 39 to 45 h after receiving oligofructose and lasting until euthanasia. The lameness was obvious, but could easily be overlooked by the untrained eye, because the heifers continued to stand and walk, and did not interrupt their eating behavior. No positive pain reactions or lameness were seen in control animals. Based on these results, we conclude that an alimentary oligofructose overload is able to induce signs of acute laminitis in cattle. This model offers a new method, which can be used in further investigation of the pathogenesis and pathophysiology of bovine laminitis.