The effect of phase-feeding on the growth performance, carcass characteristics and nitrogen balance of growing and finishing pigs.

peer-reviewedA completely randomised design experiment was conducted to determine if grouphoused grower-finisher pigs (43.9 to 95 kg) show differences in performance and nitrogen utilisation when provided with a single high lysine diet (11 g/kg) or with a mean lysine concentration of 9.5 g/kg, either as a single diet or as a series of two or four diets. Four hundred and forty pigs were assigned to four dietary treatments. The experimental treatments were (total lysine) (1) 11 g lysine/kg from day 0 to slaughter (SHD) (2) 10.5 g/kg lysine from day 0 to day 28 and 8.5 g/kg lysine from day 29 to slaughter (DFD) (3) 9.5 g/kg lysine from day 0 to slaughter (RFD) and (4) 11 g/kg lysine from day 0 to day 14, 10 g/kg lysine from day 14 to day 28, 9.0 g/kg lysine from day 28 to day 42 and 8.0 g/kg lysine from day 42 to slaughter (PFD). The estimated lysine concentration required for treatments RFD, DFD and PFD was 9.5 g/kg for group-housed pigs. All diets were pelleted and formulated to have a net energy concentration of 9.8 MJ/kg. The pigs were group fed in mixed-sex pens using single space feeders (11 pigs/feeder, 6 boars and 5 gilts). Daily feed intake was lower (P < 0.05) in treatment SHD in comparison to RFD and DFD during the overall grower-finisher period (2.08 vs 2.18 and 2.23 kg/day, respectively). Lysine conversion ratio was poorer for pigs on treatment SHD compared with DFD (P < 0.01), RFD (P < 0.01) or PFD (P < 0.001), while food conversion ratio was better for pigs on treatment SHD compared with treatments DFD (P < 0.01) and PFD (P < 0.001) during the grower-finisher period (2.31 vs 2.43 and 2.48 kg/kg, respectively). N intake and excretion were higher (P < 0.001) for pigs offered SHD compared to all other treatments (3.93 vs 3.51, 3.42, 3.40 kg and 2.56 vs 2.14, 2.03, 2.10 kg for SHD vs DFD RFD and PFD for intake and excretion, respectively). N utilisation coefficient was lower for pigs on treatment SHD than pigs on treatments DFD (P < 0.01), RFD (P < 0.001) or PFD (P < 0.01). In conclusion, phase feeding did not result in any benefit to pig performance, N excretion, N utilisation or carcass characteristics when compared with a single diet that was formulated to match the animal’s requirement for lysine (treatment RFD)

Multi-year evaluation of stocking rate and animal genotype on milk production per hectare within intensive pasture-based production systems

peer-reviewedThe objective of this experiment was to evaluate the effect of stocking rate (SR) and animal genotype (BR) on milk production, body weight (BW), and body condition score (BCS) within intensive pasture-based systems. A total of 533 lactation records, from 246 elite genetic merit dairy cows were available for analysis; 68 Holstein-Friesian (HF) and 71 Jersey × Holstein-Friesian (JxHF) crossbred cows in each of 4 consecutive years (2013–2016, inclusive). Cows from each BR were randomly allocated to 1 of 3 whole-farm comparative SR treatments, low (LSR; 1,200 kg of BW/ha), medium (MSR; 1,400 kg of BW/ha), and high (HSR; 1,600 kg of BW/ha), and remained in the same SR treatments for the duration of the experiment. The effects of SR, BR, and their interaction on milk production/cow and per hectare, BW, BCS, and grazing characteristics were analyzed. Total pasture utilization per hectare consumed in the form of grazed pasture increased linearly as SR increased: least in LSR (10,237 kg of dry matter/ha), intermediate in MSR (11,016 kg of dry matter/ha), and greatest in HSR (11,809 kg of dry matter/ha). Milk and milk solids (MS) yield per hectare was greatest for HSR (15,942 and 1,354 kg, respectively), intermediate for MSR (14,191 and 1,220 kg, respectively), and least for LSR (13,186 and 1,139 kg, respectively) with similar trends evident for fat, protein, and lactose yield/ha. At higher SR (MSR and HSR), MS yield per kg of BW per ha was reduced (0.85 and 0.82 kg of MS/kg of BW, respectively) compared with LSR (0.93 kg of MS/kg of BW/ha). Holstein-Friesian cows achieved fewer grazing days per hectare (−37 d), and produced more milk (+561 kg/ha) but less fat plus protein (−57 kg/ha) compared with JxHF cows; the JxHF cows were lighter. At similar BW per hectare, JxHF cows produced more fat plus protein/ha during the grazing season at low (1,164 vs. 1,113 kg), medium (1,254 vs. 1,185 kg), and high (1,327 vs. 1,380 kg) SR. In addition, JxHF cows produced more fat plus protein per kg of BW/ha (0.90 kg) compared with HF cows (0.84 kg). The results highlight the superior productive efficiency of high genetic potential crossbred dairy cows within intensive pasture-based production systems

Effect of stocking rate on milk and pasture productivity and supplementary feed use for spring calving pasture fed dairy systems

peer-reviewedThe productivity of grazing systems is primarily limited by the scale and efficiency of systems applied to the grazable land platform adjacent to the milking parlor. The objective of this study was to compare forage production, utilization and quality, milk production, and requirement for supplementary feeds for 2 different grazing platform stocking rate (GPSR) treatments over 4 yr. Animals were randomly allocated to 1 of 2 GPSR treatments: high-closed (HC; 3.1 cows/ha) and high-open (HO; 4.5 cows/ha), which were designed to represent alternative GPSR in a post-European Union milk quota, spring calving, pasture-based milk production system. Animal production data were analyzed using Proc MIXED of SAS with GPSR, year, and parity included as fixed effects in the final model. Within a seasonal spring calving grazing system, at high GPSR and offering moderate amounts of additional supplements based on pasture supply deficits, both systems produced more milk and fat plus protein per hectare in comparison with Irish commercial dairy farms. Although requiring additional supplementation, increased GPSR resulted in increased milk production per hectare but also in an increased requirement for concentrate and forage supplementation during lactation. No significant influence of GPSR was found on body weight and body condition score or reproductive performance during the 4-yr study period. In addition, GPSR also had no effect on pasture production, utilization, or quality during the study period. The strategic use of additional supplements with restricted pasture availability at higher GPSR maintained milk production per cow and significantly increased milk production per hectare

Effect of stocking rate and animal genotype on dry matter intake, milk production, body weight, and body condition score in spring-calving, grass-fed dairy cows

peer-reviewedThe objective of the experiment was to quantify the effect of stocking rate (SR) and animal genotype on milk production, dry matter intake (DMI), energy balance, and production efficiency across 2 consecutive grazing seasons (2014 and 2015). A total of 753 records from 177 dairy cows were available for analysis: 68 Holstein-Friesian and 71 Jersey × Holstein-Friesian (JxHF) cows each year of the experiment under a pasture-based seasonal production system. Animals within each breed group were randomly allocated to 1 of 3 whole-farm SR treatments defined in terms of body weight per hectare (kg of body weight/ha): low (1,200 kg of body weight/ha), medium (1,400 kg of body weight/ha), and high (1,600 kg of body weight/ha), and animals remained in the same SR treatments for the duration of the experiment. Individual animal DMI was estimated 3 times per year at grass using the n-alkane technique: March (spring), June (summer), and September (autumn), corresponding to 45, 111, and 209 d in milk, respectively. The effects of SR, animal genotype, season, and their interactions were analyzed using mixed models. Milk production, body weight, and production efficiency per cow decreased significantly as SR increased due to reduced herbage availability per cow and increased grazing severity. As a percentage of body weight, JxHF cows had higher feed conversion efficiency, higher DMI and milk solids (i.e., kg of fat + kg of protein) production, and also required less energy intake to produce 1 kg of milk solids. The increased production efficiency of JxHF cows at a similar body weight per hectare in the current analysis suggests that factors other than individual cow body weight contribute to the improved efficiency within intensive grazing systems. The results highlight the superior productive efficiency of high genetic potential crossbred dairy cows within intensive pasture-based milk production systems at higher SR where feed availability is restricted

Intake, efficiency, and feeding behavior characteristics of Holstein-Friesian cows of divergent Economic Breeding Index evaluated under contrasting pasture-based feeding treatments

peer-reviewedThe objective of the current study was to explore differences in dry matter intake, intake capacity, production efficiency, energy balance, and grazing behavior, of 2 divergent genetic groups (GG) of lactating Holstein-Friesian, selected using the Irish Economic Breeding Index (EBI). The GG were evaluated across 3 spring calving pasture-based feeding treatments (FT) over 3 yr. The 2 divergent GG were (1) high EBI, representative of the top 5% nationally (elite), and (2) EBI representative of the national average (NA). In each year 90 elite and 45 NA cows were randomly allocated to 1 of 3 FT: control, lower grass allowance, and high concentrate. Although FT did affect animal performance, there were few notable incidences of GG × FT interaction. The elite cows expressed lower daily milk yield (−1 kg) compared with NA. Elite cows did, however, express higher daily concentrations of milk fat (+3.7 g/kg) and protein (+2.1 g/kg) compared with NA. Daily yield of milk solids and net energy of lactation (NEL) was similar for both GG. Body weight (BW) was greater for NA (+13 kg) compared with elite, whereas mean body condition score was greater (+0.14) for elite compared with NA. Intake did not differ significantly between GG. Intake capacity, expressed as total dry matter intake/100 kg of BW, was greater with elite compared with NA. Production efficiency expressed as yield of milk solids per 100 kg of BW was greater with elite compared with NA, although milk solids/total dry matter intake did not differ between GG. Expressed as NEL as a proportion of net energy intake minus net energy of maintenance (NEL/NEI – NEM) and NEI/milk solids kg, indicated a slight reduction in the utilization of ingested energy for milk production with elite compared with NA. This is, however, suggested as favorable as it manifested as a more positive energy balance with elite compared with NA and so is likely to enhance robustness, increase longevity, and increase overall lifetime efficiency. Noteworthy was a consistent numerical trend toward more intense grazing activity with elite compared with NA cows, exhibited in the numerically greater grazing time (+19 min) and total number of bites per day (+2,591)

Economic assessment of Holstein-Friesian dairy cows of divergent Economic Breeding Index evaluated under seasonal calving pasture-based management

peer-reviewedThe objective of this study was to investigate the economic performance of 2 genetic groups (GG) of Holstein-Friesian dairy cows of divergent Economic Breeding Index (EBI), evaluated within 3 contrasting spring-calving pasture-based feeding treatments (FT). The study was a simulated economic appraisal, using the Moorepark Dairy Systems Model, a stochastic budgetary simulation model integrating biological data obtained from a 4-yr experiment conducted from 2013 to 2016. The 2 divergent GG were (1) high EBI representative of the top 5% nationally (elite) and (2) EBI representative of the national average (NA). The 3 FT were reflective of slight restriction to generous feeding. The elite GG had the lowest replacement rate, and therefore had lower replacement costs and an older and more productive parity structure. The elite GG consistently had higher sales of milk (on average +3% or +18,370 kg of milk) and milk solids (milk fat plus protein yield; +8.7% or +4,520 kg) compared with the NA GG across the 3 FT scenarios. Milk income was consequently greater for elite versus NA (on average +9.5% or +€21,489) cows. Livestock sales were greater (on average +13.2% or +€4,715) for NA compared with elite cows. Baseline net farm profit and net profit/ha at a base milk price of 29.5 cents per liter (3.3% protein and 3.6% fat) were on average €31,156, and €772 greater for elite compared with NA cows across the 3 FT. Greater profitability achieved with elite cows in each of the FT investigated demonstrated the adaptability of high-EBI cows across different levels of feeding intensities in seasonal pasture-based feeding systems. Sensitivity analysis of varying milk price and concentrate cost did not result in a reranking of GG for farm profit. This study clearly demonstrates the power of a suitably constructed genetic-selection index together with a well-considered breeding program to deliver genetics capable of favorable change to farm physical performance and profit over a relatively short duration

Analysis of milk solids production and mid-lactation bodyweight to evaluate cow production efficiency on commercial dairy farms

peer-reviewedThe efficient production of milk is an important determinant of both, farm productivity and the environmental impact of intensive dairy systems. The objective of the present study was to use a large dataset of commercial dairy cows to determine the relationship among animal breed, Irish total merit index (Economic Breeding Index; EBI), parity, and production efficiency parameters, which included milk solids (MS) production per kg of mid-lactation bodyweight (MSperBW) and the estimated net energy requirement per kg of MS produced (ENperMS). Data from 80 different spring-calving commercial dairy herds located in southern Ireland comprising 20,051 cows across 34,002 lactations from Holstein-Friesian (HF) and Jersey × Holstein-Friesian crossbred (JFX) cows were accessible for the study across 4 years. The data available included individual cow EBI, 305-day MS production, which is kg fat yield plus kg protein yield, calving and dry-off dates, and a mid-lactation bodyweight (BW) at 143 ± 26 days in milk. To evaluate the productive efficiency in this study, firstly, individual cow MSperBW was calculated by dividing 305-day MS production by mid-lactation BW, with higher values being desirable (Prendiville et al., 2009; O'Sullivan et al., 2019a). Secondly, ENperMS was established by dividing the total net energy requirement (in Unité Fourragère Lait; UFL) for an animal for maintenance (from BW), milk production, and growth (for animals up to lactation 3) by the 305-day MS production (INRA, 2010; Faverdin et al., 2011), where lower values indicate increased efficiency due to lower energy requirement per unit output. Statistical analyses were undertaken using mixed models. Overall, average MSperBW was 0.94 ±0.16 kg MS/ kg BW with large variation between animals within herds (0.42 to 1.47 kg MS/ kg BW) and between herds (0.73 to 1.14 kg MS/ kg BW). Similarly, ENperMS on farm averaged 9.8 total UFL/ kg MS ranging from 9.0 to 10.9 total UFL/ kg MS between farms. The MSperBW was significantly greater for JFX (1.01 kg MS/ kg BW) compared to HF animals (0.92 kg MS/ kg BW), resulting in a reduction in total energy requirements per kg of MS produced (ENperMS) (9.5 vs. 9.8 total UFL/ kg MS for JFX and HF, respectively). Animals with increased MSperBW produced 140 kg/cow more MS per 305-day lactation and were 58 kg lighter than lower MSperBW contemporaries. These results corroborate the benefits of both, selection on EBI and crossbreeding to increase aforementioned production efficiency parameters within intensive grazing systems. The results also provide a further compelling basis for dairy farmers to routinely weigh and milk record their herds to identify more efficient animals on which to increase animal performance and profitability in future generations

Environmental DNA (eDNA) for monitoring marine mammals: Challenges and opportunities

Monitoring marine mammal populations is essential to permit assessment of population status as required by both national and international legislation. Traditional monitoring methods often rely on visual and/or acoustic detections from vessels and aircraft, but limitations including cost, errors in the detection of some species and dependence on taxonomic expertise, as well as good weather and visibility conditions often limit the temporal and spatial scale of effective, long-term monitoring programs. In recent years, environmental DNA (eDNA) has emerged as a revolutionary tool for cost-effective, sensitive, noninvasive species monitoring in both terrestrial and aquatic realms. eDNA is a rapidly developing field and a growing number of studies have successfully implemented this approach for the detection and identification of marine mammals. Here, we review 21 studies published between 2012 and 2021 that employed eDNA for marine mammal monitoring including single species detection, biodiversity assessment and genetic characterization. eDNA has successfully been used to infer species presence (especially useful for rare, elusive or threatened species) and to characterize the population genetic structure, although additional research is needed to support the interpretation of non-detections. Finally, we discuss the challenges and the opportunities that eDNA could bring to marine mammal monitoring as a complementary tool to support visual and acoustic methods

The multi-year cumulative effects of alternative stocking rate and grazing management practices on pasture productivity and utilization efficiency

peer-reviewedThe production and utilization of increased quantities of high quality pasture is of paramount importance in pasture-based milk production systems. The objective of this study was to evaluate the cumulative effects of alternative integrated grazing strategies, incorporating alternative stocking rate (SR) and grazing severities, on pasture productivity and grazing efficiency over multiple years within farm systems using perennial ryegrass dominant pastures. Three whole-farm SR treatments were compared over 4 complete grazing seasons (2009 to 2012 inclusive): low (2.51 cows/ha; LSR), medium (2.92 cows/ha; MSR), and high (3.28 cows/ha; HSR). Each system had its own farmlet containing 18 paddocks and remained on the same treatment for the duration of the study. Stocking rate had a significant effect on all grazing variables with the exception of soil fertility status and sward density. Increased SR resulted in increased total annual net pasture accumulation, improved sward nutritive value, and increased grazed pasture utilization. Total annual net pasture accumulation was greatest in HSR [15,410 kg of dry matter (DM)/ha], intermediate for MSR (14,992 kg of DM/ha), and least for LSR (14,479 kg of DM/ha) during the 4-yr study period. A linear effect of SR on net pasture accumulation was detected with an increase in net pasture accumulation of 1,164.4 (SE = 432.7) kg of DM/ha for each 1 cow/ha increase in SR. Pregrazing pasture mass and height and postgrazing residual pasture mass and height were greatest for LSR, intermediate for the MSR, and lowest for the HSR. In comparison with the LSR, the imposition of a consistently increased grazing severity coupled with increased whole farm SR in MSR and HSR treatments arrested the decline in sward nutritive value, typically observed during mid-season. Incorporating the individual beneficial effects of SR on pasture accumulation, nutritive value, and utilization efficiency, total proportional energy (unité fourragère lait) utilization per hectare increased significantly with increasing SR (+0.026 and +0.081 for MSR and HSR, respectively). These results quantify the significant effect of grazing management practices on the feed production capability of modern perennial ryegrass pastures for intensive grazing dairy production systems. Furthermore, these results highlight the importance of consistently imposing grazing treatments over multiple years, and within integrated whole farm systems, to accurately assess the longer term effects of alternate grazing management practices on pasture productivity.the Irish Farmers Dairy Lev

Impact of a total mixed ration or pasture/pasture silage-based feeding strategy in the initial stages of lactation of spring-calving dairy cows on milk production, composition and selected milk processability parameters

peer-reviewedThe objective of this experiment was to investigate the effect of feeding strategy on milk production, composition and selected processability parameters in the initial stages of lactation. Twenty Holstein Friesian cows were allocated to one of two dietary treatments (n = 10; 7 multiparous and 3 primiparous) in a randomised complete block design for 21 d from day 10 to day 31 post-calving. Treatment 1 (pasture-based system [PBS]) was a pasture/pasture silage-based diet where cows were offered ad libitum grazed pasture or pasture silage (when weather did not permit grazing) plus 3 kg DM/d or 5 kg DM/d concentrate supplementation, respectively. On average, cows grazed pasture for 7.5 d and were fed pasture silage indoors for 13.5 d. Treatment 2 (TMR) was a total mixed ration (TMR) diet made up of concentrate, plus maize silage, pasture silage, beet pulp, soya bean meal and straw. Multiparous cows were blocked on calving date and balanced for parity and milk yield. Primiparous cows were balanced for live weight. Milk attributes pertinent to composition and functionality (e.g., fatty acids and rennet coagulation time [RCT]) were examined over a 21-d experimental period from day 10 to day 31 post-calving. Cows offered PBS tended to have a lower test day milk yield (PBS = 24.2 kg/cow vs. TMR = 26.8 kg/cow, P = 0.09) and a greater milk urea nitrogen (MUN) content compared to TMR (PBS = 0.030 g/100 g milk vs. TMR = 0.013 g/100 g milk, P < 0.001). Most notably, PBS-derived milks had a greater (P < 0.001) concentration of cis-9 trans-11 conjugated linoleic acid (CLA) compared to TMR. In conclusion, milk produced during early lactation from both feeding strategies was suitable for processing. Feeding a TMR compared with ad libitum pasture/pasture silage had no impact on average milk pH, casein concentration or RCT. Cows fed a pasture/pasture silage-based diet produced milk with a desirable RCT for milk processing, while the higher MUN content from cows offered PBS did not impact the processability of milk. Furthermore, milk from cows offered PBS had greater concentrations of cis-9 trans-11 CLA, which may offer human health benefits