Brief communication: Changes to cow behaviour when transitioning from twice a day to a 3-in-2 milking schedule

The objective of this study was to assess changes to cow behaviour when decreasing milking frequency from twice a day (TAD) to three milkings in two days (3-in-2). CowManager SensOor™ ear tags were attached to cows (n=29) for 15 days before, and 30 days after, transitioning to 3-in-2. To investigate general trends, paired t-tests were used to compare means between activity types (time spent active, highly active, not active, eating or ruminating) and milking frequency. After transitioning to 3-in-2 milking, the total time active was greater (+32.3 mins/cow/day; SEM 6.46), whilst the time spent eating (-16.2 mins/cow/day; SEM 7.57) and ruminating (-12.7 mins/cow/day; SEM 3.59) decreased. These differences were inconsistent between daylight and dark hours. These results indicate that the extra time spent in the paddock by the cows due to a 3-in-2 milking schedule was spent active, potentially due to social interaction and feed-searching behaviours, with a decrease in rumination and eating behaviours

The effects of substituting autumn nitrogen fertiliser with gibberellic acid on feed supply and milk production

The aim of this study was to investigate the use of gibberellic acid (GA) to improve feed supply and milk yield in late lactation. A grazing study at Lincoln used 36 lactating, mixed-age, Friesian-Jersey cross dairy cows balanced over three un-replicated treatments of perennial-ryegrass and white-clover pasture treated with nitrogen (N) fertiliser as urea (50 kg N/ha), GA as ProGibb® SG (8 g GA/ha) or untreated (Control). Treatments were applied in late March 2014 and grazed over 12 days in May. There was no effect of treatment on herbage pre-grazing pasture mass (2058±6.9 kg DM/ha, P=0.20), clover (3.6±0.86%, P=0.53), ryegrass (88.0±2.33%, P=0.24) or crude protein (CP) content (17.8±1.60%, P=0.31). All milk yield components: 14.6±0.40 L/day, 1.4±0.09 kg MS/cow/day, 5.4±0.33% fat and 4.4±0.21% protein were similar among treatment groups (P=0.71, 0.14, 0.16 and 0.06, respectively). Although faecal-N content of cows on GA pasture (3.72% N) was higher (P0.05) on urinary-N content (0.4 ± 0.02% N) or N excretion in milk (101±4.4 g N/cow/d). The lack of response to GA or N fertiliser highlights the importance of timing of growth promotants for late lactation

Response of simple grass-white clover and multi-species pastures to gibberellic acid or nitrogen fertiliser in autumn

Herbage dry matter (DM) production, botanical composition and nutritive value of pastures were measured in response to the application of 24 g/ha gibberellic acid (GA; 60 g ProGibb®/ha) and 50 kg N/ha nitrogen fertiliser (N; 106 kg urea/ha) in autumn. Responses were compared for simple two species grass (perennial ryegrass or tall fescue)-white clover pastures and multi-species pastures where herbs (chicory and plantain), legumes (red clover and lucerne) and prairie grass were sown with the simple mixtures. Four weeks after application, the increase in DM yield averaged across pasture mixtures relative to untreated plots was 273, 104, and 493 kg DM/ha for GA alone, N fertiliser alone, and GA and N combined, respectively. Application of GA increased the white clover percentage in all pastures except simple tall fescue pastures. The percentage of herbs in multispecies pastures was increased by application of N but not GA. Crude protein concentration was decreased by GA application in all pastures except simple ryegrass pastures. The results from this study show that it is important to consider the botanical composition of pastures when determining the effect of GA on DM yield and nutritive value

Liveweight gain per head and per ha throughout the year of lambs grazing conventional pastures and those that switch from grass to clover

Intensive lamb finishing requires a consistent supply of high quality forage throughout the year to regularly finish lambs. Per head and per ha liveweight gain of weaned lambs was compared in 13 batches of lambs on replicated irrigated farmlets for 2.5 years from conventional mixed tetraploid perennial ryegrasswhite clover pastures (Conv) and pastures that were pure white clover for spring and summer and switched to overdrilled Italian ryegrass for the winter (Switch). Seasonal differences in stocking rate (lambs/ha), liveweight gain per head and per ha were significant (P<0.05). Average daily liveweight gain/ha was significantly higher (6.01 versus 5.66 kg/ha/day for Switch and Conv, respectively, but the total grazing days were slightly lower on the Switch farmlets resulting in similar annualised liveweight gain per ha (1 800 kg) and net carcass weight (800 kg/ha) on both pasture treatments. The farmlets apparently utilised 10 000 kg DM/ha/yr of the 16 000 kg DM accumulated.This work was funded by an internal Lincoln University Research Grant INT4052

Comparison of dairy cow step activity under different milking schedules

Context. Variations in the number of milkings each day and their timing are becoming increasingly common. How these changes affect cow behaviour is poorly understood. When cows are milked less frequently, their walking to and from the dairy is reduced and their amount of time spent at pasture increases; however, the impact on activity under different milking schedules has not been measured. Aims. The objective of this study was to identify any differences in cow walking activity (steps per hour) among three milking frequencies and three milking schedules of 3-in-2 (milking three times in 2 days), at two stages of lactation (34 and 136 days in milk), over a period of 6 weeks. Time spent eating was assessed to help explain differences in activity within a day. Methods. Data were collected from five groups of 40 cows (n = 200) milked, as follows: once a day (OAD); twice a day (TAD); 3-in-2 (three groups) at intervals of 12–18–18 h, 10–19–19 h, and 8–20–20 h. All cows were fitted with AfiAct pedometers, which recorded steps per hour. Eight cows in each treatment group were also fitted with CowManager SensOor™ ear tags, which recorded minutes per hour spent eating. Key results. Cow steps per hour increased with an increasing milking frequency in both trial periods. When data associated with walking to and from milking were removed, there were still differences in cow step activity. Cows milked OAD took 30% fewer steps than TAD cows. The diurnal pattern of eating time differed between these two trial groups. The effect of milking time among the 3-in-2 trials showed that the shorter the time between the milkings on the day the cows were milked twice, the greater the number of steps per hour. There were graphical eating differences between the 8–20–20 trial group and 12–18–18 trial group on the day that cows were milked twice. Conclusions. We conclude that both the number and timings of milkings affect a cow’s step activity and grazing behaviour. Implications. Farmers should minimise the amount of time cows spend away from the paddock, especially in the afternoon, to minimise any changes to natural behaviour

Reducing milking frequency from twice each day to three times each two days affected protein but not fat yield in a pasture-based dairy system

Milking 3 times in 2 d (3-in-2) could enhance the attractiveness of the dairy workplace relative to twice-a-day milking (TAD) by reducing labor requirements for milking and increasing workforce flexibility. The objective of this study was to quantify the farm system interactions associated with milking 3-in-2 at 3 stages of lactation, with the aim of providing guidance to pasture-based dairy farmers and advisors on the likely consequences of adopting 3-in-2 milking on farm productivity and business performance. Seventy-nine multiparous and 37 primiparous cows were randomly allocated to 4 experimental farms stocked at 3.5 cows/ha. One herd was milked TAD for the whole lactation (August 2019 to May 2020), with the remaining 3 milked 3-in-2 for either the whole lactation, after December 1 when cows were an average of 101 d in milk, or after March 1 when days in milk averaged 189 d. Milking intervals over 48 h were 10-14-10-14 h for TAD and 12-18-18 h for 3-in-2. Animal, pasture, and farm system data were analyzed by linear regression, with the dependent variable being the annualized value of the performance metric of interest, and the number of days in the lactation milked 3-in-2 as the independent variable. For the proportion of the season milked 3-in-2, there was a significant effect on milk (−11%), protein (−8%), and lactose (−12%) yield per cow per year, but no effect of fat. Additionally, there was a positive effect (+6%) on body condition score before dry-off and the energy required for liveweight change (+26%), and a negative effect on the energy required for walking (−30%). There were no differences in estimated feed eaten, or pasture herbage accumulation, composition, or quality. Therefore, pasture management and feed allocation under 3-in-2 should be similar to TAD. On commercial farms, the degree to which reduced milk income can be offset by lower costs will be highly farm-specific, but opportunities for savings were identified in the results. The short walking distances on the research farm and potential to improve farm management using the time saved from fewer milkings suggests better production may be achieved with 3-in-2 milking on a commercial farm

Argentine stem weevil damage to high sugar ryegrass infected with AR1 under field conditions

Previous laboratory based studies indicate that, compared to standard cultivars, high sugar grasses (HSG) can have lower endophyte and peramine concentrations and suggest that N fertilisation may result in further reductions in endophyte and alkaloid. This could reduce the resistance of HSG, particularly at high N inputs, to Argentine stem weevil (ASW), but the interaction needs testing under field conditions. The present objective was to determine the effect of ryegrass cultivar on ASW damage, and possible interactions with N fertiliser. ASW damage, endophyte and peramine concentration were measured in three perennial ryegrass cultivars, (HSG diploid, standard diploid and a tetraploid) containing AR1 endophyte, under high and no N fertiliser application. The proportion of tillers damaged by ASW adults or larvae did not differ significantly between cultivars. However, ASW adults tended (P<0.10) to prefer the standard diploid and tetraploid cultivars over the HSG cultivar. Our results are in keeping with previous observations that higher sugar diploid cultivars may have lower endophyte and peramine content than a STD diploid cultivar, but this does not appear to have reduced resistance to ASW. Lack of differences in N content of herbage leaves, between the N fertiliser treatments, likely due to compensating changes in clover content of pastures, meant little effect of N application was seen in this field trial

Relationship between social dominance and milk production of dairy cows grazing pasture

The objectives of this experiment were to study factors determining social dominance of grazing dairy cows and the relationship between social dominance and milk production under grazing systems. A total of 252 spring calving Friesian x Jersey dairy cows in three groups differing in stocking rate and herd size grazing perennial ryegrass and white clover pasture were observed for three months in early lactation to determine their dominance value. All cows ranged in age from 2 to 11 years and live weight (LW) ranged from 340 kg to 648 kg. Dominance values were determined by social interactions indicating dominance and submission between cows. Social interactions were recorded on a win and loss basis. In all three groups, the dominance value was positively correlated (P<0.05) with age (r = 0.42 to 0.65), live weight (r = 0.33 to 0.47) and milk production (r = 0.32 to 0.42), but no relationship with body condition score was found. In conclusion, older cows with higher live weight were more dominant and tended to have higher milk productio

Supplementation of spring pasture with harvested fodder beet bulb alters rumen fermentation and increases risk of subacute ruminal acidosis during early lactation

In a cross-over design, eight rumen cannulated dairy cows were used to explore the industry-recommended method for dietary transition to fodder beet (FB: Beta vulgaris L.) on changes to rumen fermentation and pH, milk production, dry matter intake (DMI) and the risk of subacute ruminal acidosis (SARA) during early lactation. Cows were split into two groups and individually allocated a ryegrass (Lolium Perenne L.) and white clover (Trifolium repens L.) diet (HO) or the same herbage supplemented with 6 kg DM/cow of harvested fodder beet bulbs (FBH). Dietary adaptation occurred over 20 days consisting of: stage 1: gradual transition to target FB intake (days 1–12, +0.5 kg DM of FB/d); stage 2: acclimatization (days 13–17) and stage 3: post-adaption sampling (days 18–20). Response variables were analyzed as a factorial arrangement of diet and stage of adaption using a combination of ANOVA and generalized linear mixed modelling. Dietary proportion of FB represented 22, (stage 1), 32 (stage 2) and 38% (stage 3) of daily DMI. One cow during each period developed SARA from FB and the duration of low pH increased with FBH compared to the HO treatment (p < 0.01). Rumen concentrations of lactic and butyric acid increased with FBH but concentrations of acetate, propionate and total volatile fatty acids (VFA) declined by 9.3% at day 20, compared to the HO treatment (p < 0.01). Treatments did not affect milk production but total DMI with supplemented cows increased during the final stage of adaptation and feed conversion efficiency (FCE kg milk/kg DM) declined with the FBH treatment. The occurrence of SARA in 25% of animals fed FB suggest it is a high-risk supplement to animal health and further evaluation of industry-recommended methods for feeding FB at the individual-and herd-scale are needed

Rumen function and grazing behavior of early-lactation dairy cows supplemented with fodder beet

Fodder beet (FB) is a source of readily fermentable carbohydrate that can mitigate early spring herbage deficits and correct the negative energy balance experienced during early lactation in pastoral dairy systems of New Zealand. However, the low-fiber and high-soluble carbohydrate content of both FB bulb and spring herbage are factors that promote subacute ruminal acidosis, impairing rumen function and limiting the marginal milk production response to supplement. In a crossover experiment, 8 Holstein Friesian × Jersey early-lactation dairy cows were used to test the effect of supplementing 16 kg of dry matter (DM) of a grazed perennial ryegrass herbage with 6 kg of DM/d of FB bulb (FBH) versus herbage only (HO) on changes in rumen function and grazing behavior. Following 20 d of adaptation to diets, DM disappearance (%) of FB bulb (FBH cows only) and herbage were measured in sacco, separately. Cows were fasted overnight, and the ruminal contents were bailed the following morning (~0930 h) again to determine the pool size of volatile fatty acids, ammonia, and particle size of digesta, as well as to estimate the rate of ruminal outflow and degradation of neutral detergent fiber. The FBH diet did not alter DM intake, milk yield, or milk solid (fat + protein) production compared with HO. Supplementation of herbage with FB reduced ruminal pH compared with HO between ~0800 h and 1300 h each day. During each period, 1 cow experienced severe subacute ruminal acidosis (pH 180 min/d) during final adaptation to the target FB allocation. The FBH diet reduced the ruminal pool of acetate and ammonia, but increased the ruminal pool of butyrate and lactate compared with HO. When fed FB, rumination and grazing time increased and grazing intensity declined compared with cows fed HO. Despite increased rumination, the comminution of large particles declined 28% between the first and second rumen bailing when cows were fed FB, and in sacco DM disappearance of perennial ryegrass declined 18% compared with cows fed HO. These results indicate that grazing dairy cows supplemented with FB (40% of daily intake) increase rumination and mastication intensity to counteract reduced ruminal degradation of ryegrass herbage due to low ruminal fluid pH