Animal Production Science最新文献

The increasing intensification of pasture-based systems has subjected the cows to different productive environments, which could affect physiological responses and, consequently, their productive performance.

The aim was to determine the effect of contrasting housing facilities (outdoor soil-bedded vs compost-bedded pack barn) used in partial confinement in pasture-based systems, on the metabolic adaptation during early lactation and its impact on productive and reproductive performance of autumn- and spring-calving dairy cows, having as a positive control a zero-grazing confined system in compost barn.

Multiparous Holstein dairy cows that calved in autumn (n = 36) and spring (n = 48) were distributed in the following three treatments from calving to 90 days in milk (DIM): outdoor soil-bedded–grazing (OD-GRZ), compost barn–grazing (CB-GRZ), compost barn–total mixed ration (CB-TMR). Milk production, total milksolids (TMS), body condition score, non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), cholesterol, insulin, insulin-like growth factor-1 (IGF-1), and the proportion of cows with corpus luteum were determined in repeated measurements.

In both calving seasons, milk production and TMS yields did not differ between OD-GRZ and CB-GRZ, but were greater in CB-TMR (P < 0.0001). In autumn, NEFA and BHB were not affected by treatments, but cholesterol increased faster in CB-TMR (P = 0.0500). In spring, NEFA and cholesterol concentrations were not affected by treatment, but BHB remained greater in OD-GRZ until 90 DIM than in the other treatments. IGF-1 and insulin did not differ between treatments in autumn, but in spring, IGF-1 was greater in CB-TMR (P < 0.0001). The proportion of cows with corpus luteum was not different between pasture-based treatments, but both were greater than CB-TMR up to 40 DIM in autumn (P = 0.0489) and during the entire study in spring CB-TMR (P = 0.0285).

Although no differences were found among housing facilities in partial confinement, except that in spring OD-GRZ cows had greater BHB concentrations, confined cows prioritised milk production instead of reproductive function, despite presenting better energy indicators than did pasture-based cows.

Outdoor housing combined with grazing can increase the risk of greater BHB concentrations, indicative of subclinical ketosis, under heat-stress conditions, when compared with indoor housing. Confined cows increased milk production but had a delay in the resumption of ovarian cyclicity, even having a better energy status than pasture-based cows.

There is some evidence that physiological stages such as breeding, pregnancy, parturition and lactation may trigger oxidative stress. It has also been observed in several species, including sheep, that age affects their vulnerability to oxidative stress.

This study investigated the effects of supplemental β-carotene and age on the oxidative status of grazing ewes around breeding, pregnancy, parturition and early lactation as well as on their production and reproduction performance.

Hundred and four ewes were divided into two broad age groups (young = 1–3 years, and old = 4–6 years). Within age groups, ewes of similar age were randomly assigned to four treatment groups (A1, A2, A3, C) by using a completely randomised block design. The young (n = 13) and old (n = 13) sheep in Groups A1, A2 and A3 were daily drenched with 100 mg, 75 mg and 50 mg β-carotene respectively. Group C was unsupplemented (Control). Supplementation lasted 28 days before oestrus synchronisation; 14 days during oestrus synchronisation (CIDR) and hand-mating; 18 days post-hand-mating; 30 days before lambing; and 15 days after lambing. All animals were grazed on Kikuyu grass (Pennisetum clandestinum). Six ewes from each group (total = 24) were sampled for blood to measure oxidative and hormonal status during the experiment.

Supplemental β-carotene at ≥75 mg/day may act as a pro-oxidant in ruminants under oxidatively stressed conditions such as parturition. Age did not affect the ewes’ oxidative status. The supplemental β-carotene did not affect bodyweight, oestrus parameters, corpus luteum size, conception rate and litter size. Except for a tendency of lambs from supplemented ewes to have heavier weight at 15 days old (P = 0.080), age group and supplemental β-carotene did not affect the lamb mortality rate or weight at birth or 15 days old. Older ewes showed earlier and longer duration of oestrus than did younger ewes.

Supplementation of grazing ewes with β-carotene should not be ≥75 mg/day, especially at parturition period, because it may work as a pro-oxidant. The older ewes seem to have earlier oestrus with a longer duration than do the younger ones.

Caution is urged when administering high doses of β-carotene to ewes during the peri-parturient period.

Selection for growth rate has received considerable attention in beef cattle but the evidence for an improvement in the efficiency of feed conversion is equivocal.

To examine whether feed efficiency by beef cattle finished in a feedlot had been changed in response to divergence selection for growth rate.

The Angus cattle used came from three lines of cattle selected for over five generations for fast growth rate to yearling age (High-line), slow growth (Low-line), or from an unselected Control-line. Over sequential years, a cohort of steers, then of heifers and then of steers, representative of the lines, were measured for feedlot performance, and carcase- and meat-quality traits. The animals were fed a high-energy feedlot ration and after an adjustment period they underwent a performance test of at least 70 days of duration. After slaughter, muscle samples were taken for subsequent measurement of the components of the endogenous calpain proteolytic enzyme system. Their carcasses underwent a standard chiller assessment and meat samples were taken after 1 day and 14 days (steers) or 17 days (heifers) for objective measurement of tenderness.

Cattle from the High-line grew 48% faster (P < 0.05), and ate 48% more feed (P < 0.05) than did those from the Low-line, but had similar (P > 0.05) feed conversion ratio and residual feed intake. There were no differences between the High-line and Low-line in the visual meat-quality attributes of meat colour, fat colour and marbling, and no differences in the objective measurements of tenderness and connective-tissue toughness. There was no evidence of a selection response in the circulating concentrations of the metabolites and hormones measured, nor in the endogenous calpain proteolytic enzyme system in muscle.

The superior growth demonstrated by the High-line cattle over the feedlot test was accompanied by a higher feed intake, with no evidence for an improvement in feed efficiency.

Selection for growth rate is a powerful tool to alter animal performance but the beef industry needs to be cognisant of the proportional increase in feed requirement from breeding bigger animals.

The ensiling process presents losses that are associated with the fermentative profile, resulting in lower nutritional value, and lower aerobic stability of silages.

This study aimed to evaluate the effects of chitosan and microbial inoculants addition in Mombasa grass (Megathyrsus maximus) silage (MGS) fermentation profile and losses, chemical composition, in situ degradation, and aerobic stability.

Forty experimental silos (PVC tubing with 28-cm inner diameter and 25-cm height) were used in a randomised block (n = 5) design to evaluate the following treatments: (1) MGS without additives (control, CON); (2) MGS treated with 5.0 × 10⁴ colony-forming units (CFU) of Lactobacillus buchneri (NCIM 40788) per gram of fresh matter (LBB); (3) MGS treated with 1.6 × 10⁵ CFU of L. plantarum and 1.6 × 10⁵ CFU of Pediococcus acidilactici per gram of fresh matter (LPP); and (4) MGS treated with 6 g/kg DM of chitosan (CHI).

The treatments did not alter the pH, ammonia-N, butyric, and lactic acid concentrations in the silage. The use of LPP reduced the ethanol content, while CHI increased propionic and branched-chain fatty acids compared with other treatments. Fermentation losses and dry-matter recovery were not affected by treatments. Chitosan reduced the organic matter of the MGS in relation to the other treatments, without having an impact on the other variables of chemical composition. The treatments did not influence the in vitro degradation, nor the pH and temperature after aerobic exposure of the silage.

Chitosan increases ethanol compared with homofermentative lactic acid bacteria inoculation and does not affect ammonia-N of Mombasa grass silage. In addition, chitosan and microbial inoculants have limited effects on Mombasa grass silage fermentation losses, nutritional value, and aerobic stability.

Chitosan does not reduce fermentation losses or improve the nutritional value of grass silage.

For an ensiling to succeed, the knowledge about the factors that might influence the fermentation dynamics and nutrient loss is mandatory. One of the strategies is the use of additives such as tannins, as they can decrease proteolysis and increase the total organic acids.

The aim was to investigate the effects of tannins on fermentation patterns and nutritional value of sorghum silage.

Silages containing 0.0, 7.5, 15.0, 22.5, and 30.0 g/kg of tannin on fresh matter were studied. To produce the silage, the tannin was added to the forage and manually homogenised before ensiling. The study was conducted in three experiments. In the first experiment, five replications of each level of inclusion were produced and assigned in a completely randomised design. The chemical composition and fermentation patterns of all experimental units were evaluated. The second experiment consisted of analysing the aerobic deterioration by using a PET bottles system. This experiment was conducted in a completely randomised split plot, with five replications and five treatments with the inclusion of different levels of tannin (main plots) and the hours of exposure of silage to air (subplot). In the third experiment, five levels of tannin (main plots) and incubation times (subplots) were evaluated as for in situ digestibility (ruminal degradability) in a randomised blocks design with three replications (animals).

The inclusion of tannins in sorghum silage caused quadratic effects on pH, acetic acid, lactic acid, total organic acids, ammonia nitrogen, dry matter content, crude protein content and in situ digestibility, when the level varied from 10.5 to 22.7 g tannin/kg fresh matter. There was a decreasing linear effect for aerobic deterioration as increasing levels of tannin in sorghum silage.

The inclusion of tannin as an additive in sorghum silage is recommended for the production of good quality silage. The use of condensed tannins optimise fermentation patterns (especially increasing lactic acid and decreasing ammoniacal nitrogen), chemical composition, providing less aerobic deterioration and improve digestibility.

This study revealed that condensed tannins can improve fermentation patterns and the nutritive value of sorghum silage.

Managing people outside the farm family unit is a new issue for many Irish dairy farmers. In the context of rapid growth, the demand for employees has increased, creating the need for Irish dairy farmers to have human resource management (HRM) skills.

This paper explores the extent and type of HRM practices adopted by Irish dairy farmers and the factors that influence their adoption.

A questionnaire was developed, piloted, and issued to farmers on the basis of herd size and location. Data from 203 dairy farmers who employ people were analysed to examine the adoption of different HRM practices and the influence of farm characteristics, farmer demographics and farmer attitudes on their adoption. HRM practices included compliance with employment legislation, health and safety, different approaches to recruitment, workforce management and retention. The questionnaire included one or more variables for each of these HRM practices. Where more than one variable was included, an aggregate variable was developed for that practice.

Whereas, overall, there was a low level of adoption of best HRM practices, farm characteristics such as herd size and number of employees had a significant influence on farmers’ adoption of compliance with employment legislation, health and safety, recruitment, workforce management and retention practices. Demographic factors such as age, level of education, and average hours worked influenced farmers compliance with employment law legislation, workforce management practices and retention practices.

The study highlighted an overall low compliance with employment legislation and low adoption of best practices in managing staff among dairy farmers in Ireland.

This study highlighted that improvement is needed in all areas of HRM on Irish dairy farms. The findings of this study would be useful to farm advisors who support dairy farmers in improving their management of their businesses. Overall, this study has contributed to a greater understanding of the challenges in managing people in agriculture and how certain factors influences the adoption of HRM practices on dairy farms.

The energy availability for cow–calf systems is related to climate disturbances, and energy use is influenced by the age of the cows. Both factors determine the productivity and resilience of herds after climate disruption.

Identify the time needed for the herds composed of cows of a varying age to achieve resilience after energy restriction in the pre- and postpartum.

The resilience of systems was compared by deterministic dynamic simulation and herds were considered initially stable but different in (1) energy availability for all herd in the first year of production, namely at 50% (low, L), 75% (medium, M) of 100% (high, H) of the requirements according to the NRC (2000, 2016), with these energy levels being restricted to 60 days before and 60 days after the birth, and (2) the maximum age of the cull cow (lifetime, LT), namely 4 (LT4L, LT4M, LT4H), 6 (LT6L, LT6M, LT6H) of 11 (LT11L, LT11M, LT11H) years. From the second year, availability returned to meet the energy requirements of all animals. The availability of energy for the herd was simulated in natural and cultivated pasture. The productivity was determined as the relation between the kilograms of animals sold and the area used for production over a productive cycle. The system model was considered resilient when 95% of the standard productivity was reached (prior to energy restriction).

The time required to return to stability was 2 years in the LT6 and LT11, whereas LT4 required 3 years. Furthermore, LT6 had a higher productivity than did the other herds. The older the culled cow was, the greater was the change in the composition of the product commercialised.

Cows with an intermediate culling age allowed a sustainable intensification of the system, because they showed better productivity than did older cull cows. Furthermore, after climate disturbance, they presented more resilience than did younger cull cows. The level of energy restriction did not directly influence the time to resilience within each evaluated discard-age group.

Herds that culled females before reaching adult age are less resilient after disturbances, such as changes in climate or changes of any nature that interfere with reproductive rates.

In most pasture-based herds in Australia, supplementation with concentrates is normally a flat rate, with quantities determined by average cow requirements, rather than individual-cow requirements. Comparisons between flat rate and individual feeding rarely show advantages such as milk yield benefits for either. However, in pasture-based systems little is understood regarding milk production responses or levels of pasture substitution, when different groups of cows within the herd are fed concentrates at higher supplementation levels.

To investigate the effect on milk yield, feeding time, and ruminating time, of two flat-rate supplementation levels of concentrate, fed over 8 months to 180 cows selected for one of three different parameters.

Cohorts of cows were selected on contrasting differences for either milk production at the start of lactation, bodyweight, or genotype. Each cohort was divided into two balanced groups receiving either 2 or 6 kg DM/cow.day of concentrate, from approximately 12 days in milk onward. All cows remained part of the main milking herd (total herd size 320 spring-calving cows), with a similar opportunity for all cows to graze pasture or feed on supplemented grass silage during periods of pasture shortage. Milk yield was recorded at each milking and feeding behaviour continuously recorded by MooMonitor+ collars. Results were analysed for three seasonal periods of 10, 12 and 10 weeks (P1, P2 and P3 respectively) commencing in spring.

Mean marginal milk response (L milk per 1 kg DM extra of concentrate) over the trial period was 0.88 L, increasing from 0.71 L in P1, to 0.92 L in P2 and 1.03 L in P3. The high-concentrate cohorts recorded reduced feeding time per day of 37 min overall (46, 35 and 29 min for P1, P2 and P3 respectively). Significant differences were found for milk yield and feeding time between several contrasting cohorts. The lowest marginal milk response was for cross-breed cows in P1 with 0.18 L and feeding reduced by 65 min/cow.day, with the contrasting cohort of Friesian cows at a larger marginal response of 0.94 L and smaller feeding time reduction of 32 min/cow.day.

The differences among cohorts demonstrated potential for targeted concentrate feeding to specific groups of cows that respond differently in marginal milk yield and grazing behaviour.

When a significant change is made in strategic amounts of concentrate feeding, the impact not only on marginal milk response should be considered, but also on pasture intake.

Adding organic and inorganic acids to the drinking water is a potential alternative to improve production results in nursery piglets, and a strategy for reducing the use of antimicrobials.

To assess the effects of adding a blend of organic and inorganic acids to drinking water on the oxireduction potential (ORP) of water, and growth performance, biochemical, antioxidant and blood gas profiles, intestinal morphometry, biometry of organs, and intestinal microbiome of nursery piglets.

Experiment involved 1080 female piglets assessed over 30 days (Landrace × Large White, weaned at 26 days of age, weighing 6.8 ± 0.29 kg), randomly assigned to the following three treatments: (1) piglets received drinking water of natural pH of 7.39 (pH_7.39), (2) piglets received drinking water of pH of 5.31 (pH_5.31), and (3) piglets received drinking water of pH of 3.40 (pH_3.40), with eight replicates and 45 piglets/stall. Piglets had ad libitum access to diet and water throughout the experiment, and received different diets in each phase.

Receiving drinking water of pH_3.40 promoted a higher ORP, and a lower total water consumption was observed in Starter II piglets with pH_5.31. There was no treatment effect on the performance, but mortality was lower in starter piglets in the pH_3.40 treatment. Animals in the pH_3.40 treatment had lower blood alanine aminotransferase and aspartate aminotransferase activities, differing from the result obtained for total cholesterol concentrations. Animals in the pH_3.40 treatment showed a lower concentration of total protein than did piglets in the pH_7.39 treatment. Piglets in the pH_3.40 treatment had higher weights of empty stomach, spleen, and liver with gallbladder than did those in the pH_7.39 treatment. Animals in the pH_3.40 treatment showed a lower relative abundance of the Escherichia–Shigella genus and bacteria of Enterobacteriaceae family than did those in the pH_5.31 treatment.

Acidification of drinking water to pH_3.40 for nursery piglets can be used to partially increase the ORP of the water, and promote a greater weight of organs with metabolic and immune functions, while decreasing mortality. In addition, acidification of drinking water does not compromise performance or intestinal histology, but improves the profile of the intestinal microbiome in piglets.

This research has provided new information on the effects of acidifiers in the drinking water for nursery piglets and has shown their potential use for bolstering general health.

Australia is renowned for its climate variation, featuring years with drought and years with floods, which result in significant production and profit variability. Accordingly, to maximise profitability, dryland farming systems need to be dynamically managed in response to unfolding weather conditions.

The aim of this study is to identify and quantify optimal tactical livestock management for different weather-years.

This study employed a whole-farm optimisation model to analyse a representative mixed enterprise farm located in the Great Southern region of Western Australia. Using this model, we investigated the economic significance of five key livestock management tactics. These included timing of sheep sales, pasture-area adjustments, rotational grazing, crop grazing and sheep nutrition adjustments.

The results showed that, on the modelled dryland mixed-enterprise farm in the Great Southern region of Western Australia, short-term adjustments to the overall farm strategy in response to unfolding weather conditions increased expected profit by approximately 16%. Each tactic boosted profit by between A$7704 and A$53,171. However, we outline several complexities that farmers must consider when implementing tactics.

The financial gains from short-term tactical management highlighted their importance and farmers’ need to develop and apply those skills. The tactical skills promote business resilience and adaptability in the face of climate uncertainties.

The study highlighted the economic value of dynamic livestock management in response to climate variations, offering farmers in the Great Southern region the means to underpin profitable and sustainable farm practices.