The use of organic Zn sources has been claimed to reduce the environmental impact of poultry production and improve broiler performance and the quality of products. This study investigated the effects of three organic Zn supplementation strategies (i.e., TRE, total replacement; PRE, partial replacement; OTS, on-top supplementation) on tibia and blood biochemistry characteristics of broilers at high altitudes. Male Cobb 500 chicks were distributed in 54 floor pens (22 birds each) and assigned to nine experimental treatments. Birds were fed mash diets under three feeding phases until 42 days and following the standard Ecuadorian high-altitude production standard practices. The treatments were a basal diet supplemented with three inclusion rates of ZnSO4 and the same diets including or not Zn from one of two organic Zn sources (i.e., ZPR, Zn proteinate; ZAC, Zn amino acid complex). Basal diets were analyzed for Zn concentration. Tibia ash and Zn concentrations and serum biochemistry variables were determined at 21 and 42 days. The strategies to supplement organic Zn were compared with the reference treatment containing 100 ppm Zn as ZnSO4 (the standard practice; STD) using mixed models, being the block (i.e., the replication) as a random factor. The interaction of the strategy with the organic Zn source was assessed with the ANOVA and multiple comparisons. The organic Zn sources were compared considering the feed intake a random factor, and their interaction with the dietary Zn level was assessed using multiple regression. No overall effect of the Zn supplementation strategy was observed other than the reduced Zn concentration at 21 days in TRE birds. At 21 days, PRE and TRE increased the serum protein and phosphorus concentrations, respectively. At that age, TRE also increased insulin concentration, but only in the ZAC-fed birds. However, TRE produced the opposite effect on serum protein at 42 days. At the same age, ZAC-fed birds showed lower serum phosphorus concentration than ZPR-fed ones regardless of the dietary Zn supplementation level or the Zn intake. Also, ZAC under TRE produced no effect on tibia Zn concentration compared to STD, but ZPR increased it. The ZPR increased the tibia Zn concentration when fed under PRE or TRE, but not under OTS. In conclusion, the results showed no adverse effect of PRE or TRE strategies on tibia characteristics. The data indicate likely different effects of PRE and TRE on protein metabolism and a possible negative interaction of the organic Zn with a high Zn content as ZnSO4.
High-energy diets increase the risk of subacute ruminal acidosis (SARA) in ruminants. Ruminants with SARA show behavioural modifications. However, behavioural changes due to high-energy diet are often confounded with the behavioural changes due to SARA per se. Here, we aimed to disentangle diet-induced effects from SARA-induced effects on cow behaviour. We fed Holstein cows with either a low-starch diet (10.5% starch) or a high-starch diet (31.5% starch) while monitoring their SARA status. Control cows (n = 14) received the low-starch diet for 60 days. Challenge cows (n = 14) received the same low-starch diet except for 10 days when they were gradually switched from the low- to the high-starch diet and the next 14 days when they were fed the high-starch diet only. The eCow rumen bolus and the CowView activity-collar sensors were used to track the rumen pH and cows’ activities. DM intake (DMI) and milk yield of each cow were assessed on a daily basis. SARA status was defined based on a relative decrease in ruminal pH and pH variability. The high-starch diet induced SARA more often than the low-starch diet (SARA on 81% of days when receiving high-starch diet vs 8% of days when receiving low-starch diet). Cows on the high-starch diet also showed decreased milk yield and spent less time eating but ate more quickly (Challenge vs Control cows during the challenge period: milk yield 20.0 vs 18.2 L/d; % time spent eating, 22.5 vs 27.6; eating rate, 77.1 vs 69.6 g DMI/min; P (diet × period) <0.001 in all cases). Cows experiencing SARA during transition or challenge periods also tended to show lower milk yield, less time spent eating, and an increase in eating rate regardless of diet (Challenge vs Control cows: milk yield, −0.5 and −0.3 L/d, P (SARA) = 0.03; % time spent eating, −1.4 and −0.84, P(SARA) = 0.02; eating rate, +4.9 and +3.2 g DMI/min, P(SARA) = 0.06; P (diet × SARA) > 0.50). Based on these findings, an increase in eating rate, especially when combined with a decrease in milk yield, should alert farmers to the risk of ruminal acidosis.
Family succession is one of the most challenging problems of governance in agricultural systems in Brazil and worldwide. Dairy systems require particular attention in this regard, given their economic and social importance. Family succession necessitates a transfer plan for passing leadership over the dairy farm, usually from parents to their children. In this study, we sought to identify the influence of sociopsychological constructs of the theory of planned behavior on dairy farmers' intention to adopt succession planning. Questionnaires were administered to 160 dairy farmers in Paraná State, Brazil. Data were analyzed using correlation analysis and structural equation modeling. The results showed that social pressure – subjective norms was the construct that most influenced farmers' intention to adopt succession planning, followed by attitude toward the adoption of succession planning. Farmers' perceptions of their ability to carry out succession planning – perceived behavioral control did not influence their intention to adopt this strategy. There was a significant positive correlation of farm size and number of lactating cows with intention to adopt succession planning, indicating that large-scale farmers have a higher probability of practicing succession planning.
The objective of the current trial was to evaluate the effect of feeding four different forage species on milk yield and composition, including protein and fatty acid profiles, in dairy goats. Two grasses (Timothy; mown at early heading, and Italian ryegrass; mown at 25 cm height) and two legumes (Alfalfa and White clover; both mown at 10% bloom) were harvested and conserved as silage. Twelve dairy goats of three different breeds (4 Alpine, 4 Toggenburg, and 4 Saanen) in late lactation were used in a replicated 4 × 4 Latin square design. Goats were offered ad libitum access to the tested forages supplemented with 180 g/d of concentrates based on rolled barley and heat-treated soybean meal. DM intake was lower with timothy, intermediate with ryegrass and white clover, and greater with alfalfa. Milk yield was lower with timothy as compared with the other three silages. Milk fat yield was similar among treatments. Milk CP yield was lower with timothy as compared with the other three silages. Milk N efficiency (N secreted/N intake) was greater with timothy, intermediate with ryegrass, and lower with the two legume silages. The proportion of true protein as a percentage of CP was lower in milk from goats fed legume as compared with grass silages. Proportions of casein and whey protein expressed as percentages of true protein were greater with timothy, intermediate with ryegrass and white clover, and lower with alfalfa. Among grass silages, intake and milk secretion of cis-9, cis-12 cis-15 18:3 was greater with ryegrass than with timothy. As a result, the transfer efficiency from dietary intake to secretion in milk was not different between these two treatments. Fewer differences were observed regarding legume forages, as cis-9, cis-12, cis-15 18:3 intake and milk secretion were similar with alfalfa and white clover. However, the transfer of cis-9, cis-12, cis-15 18:3 from diet to milk was highest when feeding alfalfa. In conclusion, forage species fed to dairy goats influence milk composition in terms of fatty acids and protein fractions, which can potentially impact the nutritive value and technological properties of milk.

