Inclusion Of Pasture Research Articles

Case study of the market situation of calves from Alpine dairy farms and the effect of dams’ grazing during the last three months of gestation on auction parameters

The main aim of the study was to assess the recent evolution of cattle breeding in Alpine areas based on the number, quality and price of calves sold at local auctions in the South Tyrol region over the last decade, as case study. In addition, the effect of grazing during dam’s late gestation on calves’ auction quality was investigated to assess whether the inclusion of pasture in Alpine production system has an impact on auction parameters of calves beside its well-known positive effects on cattle welfare and the environment. Similarly, to other geographical areas, the study revealed that the numbers of crossbred calves (especially from specialised dairy breeds) has increased over the last years also in the Alpine area, because of more targeted breeding plans with an intensive use of beef bulls’ semen. Further, purebred calves from dual-purpose breeds (Simmental, Alpine Grey, Pinzgauer) received a higher remuneration in terms of price and market value at auction than purebred calves from specialised Holstein Friesian and Brown Swiss cows. A part of these animals could be available to support an innovative alpine meat supply chain which, if grass-fed, could further strengthen the current landscape maintenance service provided by the mountain livestock husbandry. Dams grazing during the last 90 days of gestation had a limited negative effect on calves’ liveweight and quality traits at auctions. All these results provide useful technical insights to support the switch from dairy to suckler herd system as future productive alternative for some small-scale mountain cattle farms whose viability is essential for the provision of several ecosystem services in the fragile Alpine environment.

Edaphic forms of phosphorus in no-tillage cropping sequences in the Argentine southern central Pampas

Agriculture significantly affects phosphorus (P) availability, thereby modifying P equilibrium. The objective of this study was to evaluate the effect of different crop sequences on the dynamics of soil P forms under no tillage. Soil samples were collected from a system of five sequences initiated in 1998. The agricultural sequences followed the scheme crop diversity (CD), crop-pasture (CP, without grasses), traditional crops 1 (TC1, for limited soils), traditional crops 2 (TC2), and traditional crops 3. TC3). The available P (Pe) was determined and soil P was fractionated. Organic P extracted with NaOH (PoNa) was analyzed by spectrometry UV–visible and IR. Under CP, the available P decreased in both organic and inorganic labile forms, whereas PoNa values increased. Higher Pe was observed in TC1and TC3. The E4/E6 rates showed that the systems with the lowest degree of aromaticity were CP, TC1 and TC3. These three management sequences presented high PoNa values and, from these values, CP showed lower values for Pe, indicating differences in the chemical quality of the molecule. The 1050/1260 spectra, which relates an aliphatic ester to an aromatic ester, indicated that the CP and TC3 ratios were 1.3 and 0.94, respectively. In other words, the predominant type of ester in CP is aliphatic and in TC3 predominant esters would be of the aromatic type. Crop rotations can produce changes in organic P forms, which will modify the predominant functional group and the way this nutrient interacts with the soil matrix. Inclusion of pastures in a rotation maintains plant-available P at lower levels. However, this is the sequence that keeps moderately labile P (PoNa) at higher levels.

Effects of Partial Mixed Rations on Production, Composition and Nutritional Value of Milk in Lactating Dairy Cows in Temperate Region of Argentina

The aim of the study was to determine the effect of supplementing an oat winter pasture with a total mixed ration (TMR) on lactation performance of dairy cows. Nine multiparous Holstein cows were used in a 3 × 3 Latin square design with three TMR: pasture ratios at 79:21 (T1), 58:42 (T2) and 33:67 (T3) on a dry matter (DM) basis. The response to the 100% TMR diet (TMR-100) was tested using an extra period of 14 days inmediately after finishing the Latin square schedule using the nine experimental cows. Total DM intake resulted higher in TMR-100 (28.2 (kg/cow·day) and decreased by 2.64 kg/cow·day in T1, 5.02 kg in T2 and 6.68 kg in T3. Yields of milk (31.2 kg/cow·day) and fat corrected milk (26.8 kg/cow·day) was similar between T1, T2 and T3. Milk yield resulted higher in TMR-100 (32.1 kg/cow·day) compared to T2 (30.7 kg/cow·day). Milk fat concentration (g/100 g) was higher in T2 (3.13) and T3 (3.20) compared to T1 (2.96) and TMR-100 (2.85) and milk fat yield did not differ. Milk protein content resulted higher in TMR-100 and T2 averaging 3.37 g/100 g compared to T1 (3.32 g/100 g). The lowest milk protein concentration was observed in T3 (3.29 g/100 g) that resulted only different to T2. Milk protein yield did not differ between T1, T2 and T3 averaging 1.03 kg/cow·day. A lower protein yield was detected in T2 (1.03) and T3 (1.00) when compared to TMR-100 (1.07). Efficiency of milk production (kg milk/kg DM intake) resulted higher in T3 (1.42) compared to T1 (1.25). Treatments that included pasture yielded a higher efficiency of milk production when compared to TMR-100 (1.13). Plasma urea concentration resulted lower in TMR-100 (33.8 mg/dl) with no significant differences for this parameter between the other treatments. Glucose plasma levels did not differ between T1, T2 and T3 but plasma non-esterified fatty acids (NEFA) gradually increased as the proportion of pasture was enhanced according to the lower energy intake. Plasma insulin levels were higher in TMR-100 and T2 whereas concentration of somatomedins (IGF-1) remained unaffected. Grouth hormone (GH) levels and the GH/insulin ratio were highly variable and not affected by treatments. Concentration of vaccenic and conjugated linoleic acids gradually increased with the inclusion of pasture in the diet. Supplementing a winter oat pasture with TMR may be a suitable strategy to maintain milk production with a high conversion efficiency but part of the produced milk could be sustained at the expense of endogenous energy mobilization. The conditions of replacing pasture for TMR in high yielding dairy cows should be defined taking into account the depressing effect of pasture on total DM and energy intake when fresh forage is included in high proportion in the diet.

Distribution of soil organic carbon in different size fractions, under pasture and crop rotations with conventional tillage and no-till systems

Soil organic carbon (SOC) is one of the principal indicators of soil quality. Its size fractions have been proposed as high sensitivity indicators in order to detect changes generated by different soil use and management intensities. The objective was to compare the impact of different soil management practices after 10 years on SOC distribution and its size fractions. Treatments consisted in two rotation systems (rotations of continuous annual crops and rotations of 3 years of crops and 3 years of pastures), performed with conventional tillage (CT) and no-till (NT). In 2000, NT treatments were additionally split into C 3 or C 4 summer crops. In 2003, soil was sampled at 0–3, 3–6, 6–12, 12–18, 18–40, 40–60 and 60–80 cm depths and SOC was determined. At the first four depths, SOC associated with particulate organic matter (POM-C) and with the soil mineral fraction (MAOM-C) were determined. Changes in carbon indicators (SOC and its size fractions) occurred mainly in the first 3 cm of soil, and with the exception of POM-C, were diluted when considering the 0–18 cm depth. Inclusion of pastures in the rotation was a better alternative to continuous cropping in CT systems, since it had better C indicator values. However, NT improved indicator values compared with LC, especially when C 4 species were included in the rotation; no differences were found between continuous cropping or crop-pasture rotations. These results allowed discriminate different combinations of crops and tillage systems that contribute to maintain or increase SOC, suggesting a sustainable management of the soil resource.

Sensitivity of early indicators for evaluating quality changes in soil organic matter

Labile soil carbon fractions and enzymatic activity are typically more sensitive to changes in soil management practices or environmental conditions than total soil organic matter, and consequently they are well-established as early indicators of change due to crop residue incorporation, soil use or pollution. However, less information has been reported for volcanic soils under different cropping systems where there are unique C stabilization mechanisms that promote faster accumulation of soil organic matter. The aim of our study was to compare the influence of three types of crop rotations (annual, arable crop and crop-pastures rotation) on total soil C and N as well as on several early indicators (mineralizable C and N, soil microbial biomass ( C mic), particulate organic matter (POM) and dehydrogenase activity), using a long-established experiment in volcanic soil (medial, amorphic, thermic Humic Haploxerands) of the central valley of Chile. The results found that the sensitivity to management changes varied between treatments for microbial biomass C and N, mineralized C and N, and dehydrogenase activity, and that in general these responses were proportionately greater than those found for total C. However, differences in POM-C content were less consistent. Our results confirm the value of these labile fractions and this enzyme as sensitive indicators for detecting changes in SOM in the short term both for annual arable crop and crop-pasture rotations. In conclusion, microbial biomass and dehydrogenase activity were the indicators most sensitive to changes in soil-crop management, increasing in 1–2 times their sensitivity in comparison with other indicators. However, increases in microbial biomass C in all treatments were proportionally lower than increases in organic C that resulted in low values for the microbial quotient ( C mic to C org) (although there were different between treatments) suggesting that the stabilizing mechanisms acting in volcanic soils can result in proportionally larger amounts of stabilized organic matter that are contained in the total organic C of the soil. POM was not an appropriate indicator of changes in soil organic matter (SOM) for this volcanic soil under distinct crop rotations. The inclusion of pastures (5 years of alfalfa or white clover) in the annual crop rotation promotes the increase of both total and labile fractions of soil organic matter in comparison with annual arable crop rotations, while the inclusion of short rotation pastures (2 years of red clover) had a minimum effect on biological parameters.

Supplementing total mixed rations with pasture increase the content of conjugated linoleic acid in milk

Forty-five Holsteins cows in early to mid-lactation were used to evaluate the milk fatty acid composition of three feeding systems that combined pasture and total mixed ration (TMR) in a 19-week experiment. The three treatments were: (1) pasture plus concentrate (PC), (2) pasture plus TMR (PTMR), and (3) TMR. The content of short- and medium-chain fatty acids (FA) decreased from 11.3 to 9.0 g/100 g of FA and from 40.5 to 36.5 g/100 g, respectively, from the TMR to the PC treatment. The content of long-chain FA increased from 47.7 to 53.8 g/100 g as the amount of pasture dry matter (DM) intake increased from the TMR to the PC treatment. The content of saturated FA was lower (55.5 g/100 g versus 60.1 g/100 g) and the content of unsaturated FA was higher (43.9 g/100 g versus 38.6 g/100 g) in the PC treatment versus the PTMR and TMR treatments. As the amount of pasture DM intake increased from the TMR to the PC treatment, the content of conjugated linoleic acid (CLA) increased from 0.59 to 1.21 g/100 g, resulting in a 42 and 105% increase for the PC treatment compared to the PTMR and TMR treatments, respectively. The increase in CLA content in milk with inclusion of pasture was primarily associated with a higher intake of C18:3 and a higher delivery of trans11 C18:1 to the mammary gland.

Economic evaluation of strategies for management of herbicide resistance

Abstract Resistance of weeds to chemical herbicides is a problem of rapidly growing importance in agriculture. In Australia there has been a very rapid growth in the occurrence of resistance in populations of annual ryegrass ( Lolium rigidum ) growing as a weed in continuous cropping rotations. in this paper a dynamic model of herbicide resistance development in ryegrass is used to examine various aspects of weed management. The model is used to identify optimal combinations of chemical and non-chemical weed control for a range of scenarios. It is found that the period for which herbicide use can profitably be continued prior to onset of resistance is highly sensitive to the effectiveness of the non-chemical control. It is shown that under plausible conditions, the inclusion of pasture in the rotation to delay the onset of herbicide resistance (with weed seed reductions through grazing) can be a profitable strategy.

Development of herbicide resistance in annual ryegrass populations (Lolium rigidum Gaud.) in the cropping belt of Western Australia

Annual ryegrass (Lolium rigidum) samples from the cropping belt of Western Australia were screened for herbicide resistance in 1992 and 1993. There was a strong relationship between the number of applications of a herbicide group and development of resistance in ryegrass populations. Resistance was detected in all populations that received >7 applications of aryloxyphenoxypropionate (AOPP) and cyclohexanedione (CHD) herbicides or >4 applications of sulfonylurea (SU) herbicides. Some AOPP-resistant populations had also developed crossresistance to SU herbicides, a group with a different mode of action. Inclusion of pasture in the rotation had little effect on the relationship between the number of applications of the AOPP and SU herbicides and development of resistance. A subset of 33 populations was chosen to determine the response of triasulfuron-resistant populations to sulfometuron, a nonselective SU herbicide which has been shown to be effective against metabolic-type resistance. All triasulfuron-resistant populations were found to be resistant to sulfometuron, possibly due to insensitive acetolactate synthase (ALS) in these ryegrass populations. Some of these SU-resistant populations were also resistant to the imidazolinone herbicide imazethapyr, another ALS inhibitor. However, there were several populations with a high level of SU resistance that were still susceptible to imazethapyr.