A three-year comparison of once-a-day and twice-a-day milking in seasonal-calving pasture-based systems.

Globally, the majority of dairy cows are milked twice a day (TAD); however, in pasture-based production systems, such as in Ireland, the idea of milking once a day (OAD) is being considered for reasons such as improved work-life balance. The immediate effects within a lactation, as well as the multilactation consequences of OAD, compared with TAD milking, require understanding. The objective of this randomized experiment was to compare OAD and TAD milking, over a 3-yr period, by examining the differences in milk production and composition, body weight (BW), body condition score (BCS), dry matter intake (DMI), udder characteristics, locomotion score, and milking time. Over the 3-yr period, 83 cows were enrolled in the experiment; 32, 44, and 48 cows in yr 1, 2, and 3 of the experiment, respectively. Each year, 23% of the herds were primiparous animals, while the remainder were second lactation or greater in parity. All cows were milked in the morning at 0700 h; only cows milked TAD were milked a second time each day at 1600 h. Cows rotationally grazed pastures for the duration of the lactating period and were housed during the nonlactating period. Milking cows OAD reduced cumulative milk yield by 26%, and milk solids yield (kg of fat + kg of protein) by 21%, across the 3 yr of the experiment when compared with cows milked TAD which produced 4,126 and 365 kg/cow, respectively. A contributory factor to the reduced production was a shorter lactation length (9.7 d) of the cows milked OAD compared with TAD (294 d). Milk fat percent of cows milked TAD was similar for all 3 yr of the study (5.05%), whereas milk fat percent of the cows milked OAD increased year on year, with each year being greater than the previous year (5.02%, 5.32%, and 5.70% for yr 1, 2, and 3; respectively). Milk protein percent was greater (+0.19%) for cows milked OAD compared with TAD which was 3.78%. Compared with cows milked TAD, total DMI for cows milked OAD was 22% less at the start of lactation (<167 d), but as the lactation progressed (>167 d) we observed no difference in DMI between treatments. Similar to the literature, milking cows OAD significantly increased average somatic cell score, both during (+16%) and at the end of lactation (+19%), compared with milking cows TAD which were 4.69 and 4.79, respectively. We detected positive aspects associated with OAD milking such as greater BW, BCS, and fertility performance. Milking OAD reduced both milking time per cow per day (reductions ranged from 34% in the first 4 mo of lactation to 43% during mo 5-9 of lactation) and milking time per liter of milk (-3.5 s/L) throughout lactation, leading to less labor inputs on-farm which can have positive implications for farmer work-life balance. The significant time saving and potential savings in costs (e.g., electricity) need to be considered in conjunction with the milk production reduction when considering OAD milking for the entire lactation.

'I am an Intensive Guy': The Possibility and Conditions of Reconciliation Through the Ecological Intensification Framework.

The need for better conciliation between food production and environmental protection calls for new conceptual approaches in agronomy. Ecological intensification (EI) is one of the most encouraging and successful conceptual frameworks for designing more sustainable agricultural systems, though relying upon semantic ambivalences and epistemic tensions. This article discusses abilities and limits of the EI framework in the context of strong social and environmental pressure for agricultural transition. The purpose is thus to put EI at stake in the light of the results of an interdisciplinary and participatory research project that explicitly adopted EI goals in livestock semi-industrialized farming systems. Is it possible to maintain livestock production systems that are simultaneously productive, sustainable, and viable and have low nitrate emissions in vulnerable coastal areas? If so, how do local stakeholders use these approaches? The main steps of the innovation process are described. The effects of political and social dynamics on the continuity of the transition process are analyzed, with a reflexive approach. This experiment invites one to consider that making EI operational in a context of socio-technical transition toward agroecology represents system innovation, requiring on-going dialogue, reflexivity, and long-term involvement by researchers.

How the Green Architecture of the 2023-2027 Common Agricultural Policy could have been greener.

A new 5-year Common Agricultural Policy has been in place since January 2023. Like its predecessors, this new policy will fail to deliver significant climatic and environmental benefits. We show how the Green Architecture of the policy relying on the three instruments of conditionality, eco-schemes, and agri-environment and climate measures could have been used more consistently and effectively. Our proposals are based on core principles of public economics and fiscal federalism as well as on research results in agronomy and ecology. Conditionality criteria are the minimal requirements that every agricultural producer must meet. Farmers should be rewarded for efforts that go beyond these basic requirements through eco-schemes for global public goods complemented by agri-environment and climate measures centred on local public goods. Eco-schemes should cover the whole agricultural area by targeting permanent grasslands, crop diversification, and green cover and non-productive agro-ecological infrastructures. We discuss trade-offs that our proposals could generate.

Is there adaptation of the exocrine pancreas in wild animal? The case of the Roe deer.

BACKGROUND: Physiology of the exocrine pancreas has been well studied in domestic and in laboratory animals as well as in humans. However, it remains quite unknown in wildlife mammals. Roe deer and cattle (including calf) belong to different families but have a common ancestor. This work aimed to evaluate in the Roe deer, the adaptation to diet of the exocrine pancreatic functions and regulations related to animal evolution and domestication. RESULTS: Forty bovine were distributed into 2 groups of animals either fed exclusively with a milk formula (monogastric) or fed a dry feed which allowed for rumen function to develop, they were slaughtered at 150 days of age. The 35 Roe deer were wild animals living in the temperate broadleaf and mixed forests, shot during the hunting season and classified in two groups adult and young. Immediately after death, the pancreas was removed for tissue sample collection and then analyzed. When expressed in relation to body weight, pancreas, pancreatic protein weights and enzyme activities measured were higher in Roe deer than in calf. The 1st original feature is that in Roe deer, the very high content in pancreatic enzymes seems to be related to specific digestive products observed (proline-rich proteins largely secreted in saliva) which bind tannins, reducing their deleterious effects on protein digestion. The high chymotrypsin and elastase II quantities could allow recycling of proline-rich proteins. In contrast, domestication and rearing cattle resulted in simplified diet with well digestible components. The 2nd feature is that in wild animal, both receptor subtypes of the CCK/gastrin family peptides were present in the pancreas as in calf, although CCK-2 receptor subtype was previously identified in higher mammals. CONCLUSIONS: Bovine species could have lost some digestive capabilities (no ingestion of great amounts of tannin-rich plants, capabilities to secrete high amounts of proline-rich proteins) compared with Roe deer species. CCK and gastrin could play an important role in the regulation of pancreatic secretion in Roe deer as in calf. This work, to the best of our knowledge is the first study which compared the Roe deer adaptation to diet with a domesticated animal largely studied.

Is caseinomacropeptide from milk proteins, an inhibitor of gastric secretion?

The aim of this work was to study, in vivo, the effect of the ingestion of not glycosylated caseinomacropeptide (CMP) on gastric secretion. In Experiments #1 and #2, 7 calves fitted with a gastric pouch received either a diet without CMP (C diet) or C diet in which CMP was introduced (equal to and 5 folds that of CMP quantity contained in cow milk, diets CMP1 and CMP5, respectively). In Experiment #3, 2 calves (with gastric pouch) were fed C diet followed by an "iv perfusion" of CMP. In Experiment #4, 25 calves fed either C, CMP1 or CMP5 diets were fitted with a blood catheter for sample collections. The quantities of daily gastric secretions seemed few modified by CMP ingestion but the profile of these secretions was changed along the day. The most important result is that CMP can inhibit gastric secretions (mainly hydrochloric acid) stimulated by the meal, but there was no dose-dependent response. No similar observations were obtained after perfusion of CMP in jugular vein. CMP was not detected in blood. Results obtained in our experiments are not in favor of its significant intestinal absorption. Gastrin, somatostatin and VIP could be implicated in the mechanisms of regulation.

Hierarchy of factors affecting behavioural signs used for oestrus detection of Holstein and Normande dairy cows in a seasonal calving system.

As oestrous expression of dairy cows has decreased over the last decades oestrus detection has become more difficult. The objective of this study is to identify the main factors that affect oestrus detection in seasonal calving dairy cows, and to establish their relative importance. In each of 5 years 36 Normande and 36 Holstein cows were assigned to a Low or High winter-feeding level group. Half of each group was then assigned to a Low or High pasture-feeding group. The Low-Low strategy resulted in the lowest milk yield and the greatest body condition (BC) loss from calving to nadir BC score (6302 kg; -0.98 unit). The High-High strategy had the converse effect (7549 kg; -0.75 units). Low-High and High-Low strategies had intermediate values. The Normande cows had lower milk yield and BC loss than Holstein cows (6153 kg versus 7620 kg; -0.82 unit versus -1.20 unit). A database of 415 observed spontaneous oestruses was created. Oestruses were classified according to detection signs: (1) standing to be mounted, (2) mounting without standing, (3) other signs without standing or mounting (slight signs). Presence of another cow in oestrus, access to pasture, Normande breed and Low-Low strategy increased standing detection. In the Normande breed, 97% of oestruses were detected by standing while combining the presence of a herdmate in oestrus and access to pasture with a milk production of less than 6550 kg. Holstein cows had a higher frequency of slight signs oestruses than Normande ones, which was associated with a decreased subsequent calving rate (P<0.05). In multiparous Holstein cows, the odds of slight signs detection was multiplied by 7.8 for the High-High group in comparison with the Low-Low group (P<0.05). In our study milk yield had an effect on oestrus detection which was not explained by BC loss. As High-High cows produced more milk than others, we logically found that an increase in milk yield increased slight signs detection. Conversely, as they lost less BC than others, BC loss improved the chance of standing or mounting detection. These two results show that an increase in milk yield may reduce oestrous behaviour even if BC loss is moderate. Oestrus detection is crucial in seasonal compact calving systems. High phenotypic milk yields appear unsuitable with such systems in regard to depressed oestrous behaviour.

A new role of phosphopeptides as bioactive peptides released during milk casein digestion in the young mammal: regulation of gastric secretion.

The aim of this work was to study in vivo the effect of ingestion of phosphopeptides (PP) alone or associated with caseinomacropeptide (CMP) on gastric secretion and to elucidate some possible mechanisms involved. Seven calves fitted with a gastric pouch received either a diet based on whey proteins without PP and CMP (C diet) or C diet in which PP or PP+CMP was introduced at concentrations similar to that of PP or PP+CMP in cow milk (PP diet and PP+CMP diet, respectively). Gastric juice secretion was measured during successive periods throughout the day. Twenty-four calves were fitted with a catheter introduced in one external jugular vein for blood sample collections. The daily secretion of electrolytes decreased with the presence of PP or PP+CMP in the diet. During the day, peptide supplementation in the diet resulted in (1) short term (1st-2nd postprandial h), a decrease of secreted quantities of gastric juice, enzymes and electrolytes, (2) long term (7-24h after the morning meal), a decrease of electrolyte secretions. Intervention of gastrin, CCK, somatostatin and BPP could be probable. Globally, inhibition of gastric secretions seemed more important when PP was given in association with CMP in the diet rather than alone. CMP and PP may have short and long term action respectively over the 24h day. To our knowledge, it is the first time that phosphopeptides coming from milk casein digestion are demonstrated to inhibit gastric secretion. Therapeutic uses are suggested.