Symposium review: Decomposing efficiency of milk production and maximizing profit

The dairy industry has focused on maximizing milk yield, as it is believed that this maximizes profit mainly through dilution of maintenance costs. Efficiency of milk production has received, until recently, considerably less attention. The most common method to determine biological efficiency of milk production is feed efficiency (FE), which is defined as the amount of milk produced relative to the amount of nutrients consumed. Economic efficiency is best measured as income over feed cost or gross margin obtained from feed investments. Feed efficiency is affected by a myriad of factors, but overall they could be clustered as follows: (1) physiological status of the cow (e.g., age, state of lactation, health, level of production, environmental conditions), (2) digestive function (e.g., feeding behavior, passage rate, rumen fermentation, rumen and hindgut microbiome), (3) metabolic partitioning (e.g., homeorhesis, insulin sensitivity, hormonal profile), (4) genetics (ultimately dictating the 2 previous aspects), and (5) nutrition (e.g., ration formulation, nutrient balance). Over the years, energy requirements for maintenance seem to have progressively increased, but efficiency of overall nutrient use for milk production has also increased due to dilution of nutrient requirements for maintenance. However, empirical evidence from the literature suggests that marginal increases in milk require progressively greater marginal increases in nutrient supply. Thus, the dilution of maintenance requirements associated with increases in production is partially overcome by a progressive diminishing marginal biological response to incremental energy and protein supplies. Because FE follows the law of diminishing returns, and because marginal feed costs increase progressively with milk production, profits associated with improving milk yield might, in some cases, be considerably lower than expected.info:eu-repo/semantics/publishedVersio

Enhanced-growth feeding programs for dairy calves : nutrition, management, and long-term effects /

Consultable des del TDXTítol obtingut de la portada digitalitzadaEs varen realitzar quatre estudis per avaluar l'efecte de donar molta llet a les vedelles lactants durant la fase de lactància, per tal de millorar el creixement de les vedelles de reposició durant aquest període. Els vedells que varen rebre una alimentació mÎs rica en llet durant la lactància van créixer més, però van menjar menys pinso que els vedells que seguien una alimentació convencional. Tot i així, després del deslletament ambdos nivells d'alimentació van presentar el mateix ritme de creixement i consum de pinso. Per altra banda, el fet de criar vedells en grup i amb un nivell elevat de llet durant la lactància, no va estimular el consum de pinso en comparació als vedells criats individualment i alimentats amb un alt nivell de llet. A més a més, els index productius de creixement i l'aparició de problemes de salut van ser similar en vedells criats en grup o individualment. En general, els vedells criats en grups varen augmentar els comportaments orals amb finalitat no nutritiva, i disminuir els comportaments de succions creuades i succions dirigides a la zona pèlvica al llarg de l'estudi. Tant els vedells criats en grups com individualment van presentar un lleuger augment de la conducta de «selfgrooming» al llarg de l'estudi. La concentració plasmàtica d'amino àcids va indicar que cap amino àcid limitava el creixement durant la fase de lactància quan les vedelles es varen criar seguint una alimentació amb un alt nivell de llet. No obstant, en els vedells que es van criar convencionalment, les concentracions plasmàtiques de fenilalanina i triptòfan una hora després de menjar estaven positivament correlacionades amb el guany mig diari, i negativament correlacionades amb la concentració plasmàtica d'urea, suggerint que els creixements dels vedells criats convencionalment podria estar limitat per l'aportació d'aquests dos amino àcids quan s'utilitza una llet maternitzada i un pinso similar al d'aquest estudi. Per altra banda, la menor excreció urinària de derivats púrics observada en vedelles alimentades amb un alt nivell de llet en comparació a les vedelles criades convencionalment, va indicar un menor fluxe microbià a nivell duodenal que podria estar relacionat amb la menor ingestió de pinso en les vedelles alimentades amb un nivell elevat de llet durant el periode de lactància. A més a més, els vedells alimentats amb un nivell alt de llet durant la fase de lactància van tenir una menor digestibilitat aparent dels nutrients del pinso la setmana després del deslletament en comparació als vedells alimentats convencionalment. Les concentracions sèriques de glucosa i insulina varen ser majors en vedells alimentats amb un alt nivell de llet que en vedells alimentats convencionalment. Però, les concentracions sèriques d'urea no varen seguir un mateix patró en els diferents estudis. En dos dels tres estudis, les concentracions sèriques d'urea van ser superiors en vedells criats convencionalment que en aquells alimentats amb un alt nivell de llet, però en l'altre estudi les concentracions sèriques d'urea varen ser similars en ambdos nivells d'alimentació. Finalment, l'avantatge de pes viu aconseguit durant la fase de lactància en vedelles seguint una alimentació amb un alt nivell de llet es manté numèricament superior fins els 385 d d'estudi, però aquest avantatge no redueix l'edat a la primera cubrició, i ni millora la fertilitat a la primera cubrició en vedelles criades amb un alt nivell de llet en comparació amb vedelles criades convencionalmentFour studies were conducted to evaluate the effects of feeding dairy calves on an enhanced-growth feeding program. Enhanced-fed calves showed greater average daily gain, but lower starter dry matter intake than calves fed conventionally during the preweaning period. However, after weaning both feeding programs resulted in similar rates of growth and starter consumption. On the other hand, rearing enhanced-fed calves in groups did not stimulate starter intake. Also, performance was not decreased nor the occurrence of health problems increased when calves were reared in groups. In general, calves raised in groups increased non-nutritive oral behavior, and decreased cross-sucking and inter-sucking behaviors throughout the study, and both individually-and groupedreared calves slightly increased self-grooming behavior throughout the study. Plasma amino acid concentrations indicated that none amino acid was limiting growth during the preweaning period when calves were raised following an enhanced-growth feeding program. Nevertheless, with calves conventionally-fed, plasma phenylalanine and tryptophane concentrations one hour after feeding were positively correlated with average daily gain and negatively correlated with plasma urea concentrations, suggesting that growth of calves following conventional feeding programs could be limited by the supply of these two amino acids when using milk replacers and starters similar to those used in the present study. On the other hand, lower total purine derivatives urine excretions were observed in enhanced-compared with conventionally-fed calves, suggesting a lower microbial duodenal flow that was probably related to the low starter intake during the preweaning period of enhanced-fed calves. Furthermore, apparent nutrient starter digestibility was lower in enhanced-compared with conventionally-fed calves the week after weaning. Serum glucose and insulin concentrations were greater in enhanced-than in conventionally-fed calves, but serum urea concentrations did not follow a common pattern among studies. In two out of the three studies, serum urea concentrations were greater in conventionally-than in enhanced-fed calves, but in the other studies there were no differences between treatments. Body weight advantage obtained with enhancedgrowth feeding program was numerically maintained later in life, but this advantage did neither reduce the age at breeding, and nor improve fertility at first breeding of enhancedfed calves

Feeding pasteurized waste milk to preweaned dairy calves changes fecal and upper respiratory tract microbiota

In the present study bacterial communities from both, the gastrointestinal and respiratory tract of pre-weaned dairy calves fed two different milk-feeding programs were characterized using 16S rRNA gene sequencing. Twenty female Holstein calves (38.8 ± 1.40 kg of BW) were fed pasteurized waste milk (pWM) containing residues of various antimicrobials. Twenty additional calves (38.1 ± 1.19 kg of BW) were fed milk replacer (MR) with similar nutrient composition (27.5% crude protein, 32.1% fat) compared to waste milk (28.6% crude protein, 30.0% fat) from day 1 to weaning at day 49 of study. Fecal samples and nasal swabs were collected on day 42 only from calves that were not treated with therapeutic antibiotics throughout the study, which were 8 MR and 10 pWM calves. To assess the impact of the two feeding regimes on the fecal and nasal microbiota, α and β-diversity measures were calculated, and the relative abundance of operational taxonomic units (OTUs) at different taxonomic levels was determined for each sample. In general, Chao1, PD Whole Tree, and Shannon diversity indices were similar for the fecal and nasal bacterial communities of calves regardless of the feeding regime. However, principal coordinate analysis based on unweighted Unifrac distances indicated differences in the structure of bacterial communities of calves fed milk replacer compared with those from calves fed pasteurized waste milk. The relative abundance of the Streptococcaceae family and the genus Histophilus was greater (P < 0.05) in the nasal microbiota of calves fed milk replacer than in those fed pasteurized waste milk. However, the genus Prevotella tended (P = 0.06) to be more relatively abundant in the respiratory tract of calves fed pasteurized waste milk than in those fed milk replacer. Differences in relative abundances of bacterial taxa in gut microbiota were only observed at the phylum level, suggesting that antimicrobial residues present in waste milk have a non-specific influence at a lower taxonomical level.info:eu-repo/semantics/publishedVersio

Short Communication: The biological value of transition milk: analyses of Immunoglobulin G, IGF-I and Lactoferrin in primiparous and multiparous dairy cows

Colostrum (the first mammary gland secretion after calving) is known to contain high concentrations of nutrients as well as bioactive substances (including immunoglobulins, growth factors, and antimicrobial factors) to ensure neonatal survival. Due to its immunomodulatory, antibacterial, and antiviral activities, bovine colostrum has been used not only in calves but also in the prevention and treatment of human gastrointestinal and respiratory infections. Transition milk is the mammary secretion from the second milking to the sixth, which may contain these bioactive compounds to a lesser extent. The objective of the present study was to measure IGF-I, immunoglobulin G (IgG), and lactoferrin (LTF) concentrations in colostrum and transition milk of primiparous and multiparous cows to further assess its potential use in veterinary and nutraceutical applications. The results demonstrated that the concentrations of these three bioactive molecules decrease from the first milking to the tenth. Concentrations of IGF-I and LTF were greater in multiparous than in primiparous cows. Also, lactation number interacted with milking number in IGF-I, since primiparous cows had a smoother decline of IGF-I concentrations than multiparous ones. Overall, transition milk from the second milking showed a 46% decrease in the analysed colostrum bioactive molecules. Therefore, further studies are needed to apply this knowledge in neonate farm management practices or in developing pharmaceutical supplements from farm surpluses.info:eu-repo/semantics/publishedVersio

Short communication: A milk replacer aversion model in calves to test flavour-masking effects

This study aimed to evaluate the availability of two sensory additives (SAs) to masque non-palatable ingredients commonly present in milk replacers (MRs). Both SAs were based on a synergistic mixture of non-nutritive flavouring substances with four taste categories (sweet, umami, sour, and salty); the only difference between them was the inclusion of polyols, which were not included in SA2. Two experiments were conducted for this purpose. In Experiment 1, an MR aversion model was developed using 24 Holstein male calves (7 ± 0.9 d of age and 43.3 ± 1.39 kg of body weight [BW]). In the first two weeks of the study, calves were fed increasing amounts of MRs until the animals were able to consume 8 L/d at 15% dry matter (DM) concentration for two feedings per day. Thereafter, MR aversion was induced in half of the calves by adding a mixture of bitter taste feed additives (Bittermix) from days 14 to 22 of the study (aversion week). The daily MR intake and eating rate were recorded from the two previous days of the challenge and during the aversion week. In Experiment 2, the same model was used with 37 Holstein male calves (6 ± 0.9 d of age and 40.2 ± 1.40 kg of BW). Owing to health issues in this experiment, the aversion week was postponed at 38.5 ± 1.12 d of age until the animals were able to consume at least 90% of 8 L/d at 12.5% DM concentration. The aversion test was performed as follows: no supplementation (CTRL), Bittermix at 30 g/kg of dry MR (BM), BM plus SA1 at 2 g/kg of dry MR (SA1), and BM plus SA2 at 2 g/kg of dry MR (SA2). Data were analysed with a generalised mixed model that accounts for the fixed effects of MR supplementation, the meals during the aversion week, the interaction of the MR supplementation and meals, and a calf as a random effect. In the aversion test of Experiment 1, calves that were fed Bittermix showed an increase in the incidence and amount of MR refusals (P < 0.05) compared with CTRL calves. In Experiment 2, the incidence of refusal and time devoted to consuming MR were similar in all treatments. However, the eating rates were greater (P < 0.01) in CTRL and SA2 than in BM and SA1. Adding a mixture of bitter tasting feed additives in the MR changed the feed intake parameters of the calves. The addition of a specific sensory additive, namely, SA2, reversed the negative effects caused by the bitter products.info:eu-repo/semantics/publishedVersio

Effectiveness of precision feeding in reducing N excretion in dairy cattle

Two periods enrolling 56 (milk yield 36.2 ± 7.91 kg/d) and 58 (milk yield 32.4 ± 4.99 kg/d) grouped-fed dairy cows were performed to evaluate nutrient adjustment and N emissions of a precision feeding strategy. Pens blocked by parity were randomly assigned to a conventional (CONV) or to a precision feeding scheme (PREC) for a 21-d period. The CONV group was offered a total mixed ration (TMR, 6.82 and 6.65 MJ of NEl/kg of DM, in period 1 and 2, respectively, and 165 g of CP/kg of DM in both periods; whereas PREC cows were fed a partial mixed ration (PMR, 6.65 and 6.40 MJ of NEl/kg of DM, 135 and 137 g of CP/kg of DM, in period 1 and 2, respectively) and a concentrate feed supplemented twice daily in the milking parlour, which contained different quantities of soybean meal, corn meal, and wheat middling’s according to estimated nutritional needs of each cow above those supplied by the consumption of PMR. Individual daily nutritional needs and nutrients consumed from the PMR were calculated using a 10-d rolling average of performance data (milk yield and concentration of its components, and BW daily recorded in both periods). A N balance using urine and fecal spot sampling during the last 3 d of the study was performed in period 1, and stored manure gaseous emissions (ammonia, methane, nitrous oxide, and carbon dioxide) were measured for 2 wk in period 2. After 2 wk of adaptation to the diet, 82 cows homogeneously distributed in 4 DIM categories: early DIM ( 220) were used to assess how energy and protein requirements were adjusted using both feeding system. Dairy cows in both feeding systems were energetically overfed, and CONV cows tended to be more CP overfed in mid-late and late DIM cows than PREC fed cows. Total daily N urine excretion, and milk N urea concentration were greater in CONV than in PREC cows. There were no differences in ammonia and nitrous oxide emissions from the manure storage between PREC and CONV cows; however, methane and carbon dioxide emissions from manure increased by 55% and 15%, respectively in PREC fed cows. Precision feeding system based on preceding average daily milk yield and composition can reduce N excretion without affecting short-term milking performance but increasing C gaseous emissions from manure.This research was carried out in the framework of the project CIRCULAR AGRONOMICS (nº contract agreement 773649). IRTA thanks the support of the CERCA Program and the Consolidated Research Groups of Sustainability in Biosystems (ref. 2021 SGR 01568) and Sustainable Animal Husbandry (ref. 2021 SGR 01552), both from the Generalitat de Catalunya. Lluis Morey thanks Universitat Politècnica de Catalunya and the financial support of AGAUR, of the Generalitat de Catalunya (grant reference number 2019FI_B 00694)info:eu-repo/semantics/publishedVersio

Using compositional mixed-effects models to evaluate responses to amino acid supplementation in milk replacers for calves

The consequences of supplementing Lys, Met, and Thr in milk replacers (MR) for calves have been widely studied, but scarce information exists about potential roles of other AA (whether essential or not). The effects on growth performance of supplementation of 4 different AA combinations in a mixed ration (25.4% crude protein and 20.3% fat) based on skim milk powder and whey protein concentrate were evaluated in 76 Holstein male calves (3 ± 1.7 d old). The 4 MR were as follows: CTRL with no AA supplementation; PG, supplying additional 0.3% Pro and 0.1% Gly; FY, supplying additional 0.2% Phe and 0.2% Tyr; and KMT, providing additional 0.62% Lys, 0.22% Met, and 0.61% Thr. All calves were fed the same milk allowance program and were weaned at 56 d of study. Concentrate intake was limited to minimize interference of potential differences in solid feed intake among treatments. Animals were weighed weekly, intakes recorded daily, and blood samples obtained at 2, 5, and 7 wk of study to determine serum urea and plasma AA concentrations. Plasma AA concentrations were explored using compositional data analysis, and their isometric log-ratio transformations were used to analyze their potential influence on ADG and serum urea concentration using a linear mixed-effects model. We detected no differences in calf performance and feed intake. Plasma relative concentration of the AA supplemented in the KMT and PG treatments increased in their respective treatments, and, in PG calves, a slight increase in the proportion of plasma Gly, Glu, and branched-chain AA was also observed. The proportions of plasma branched-chain AA, His, and Gln increased, and those of Thr, Arg, Lys, and Glu decreased with calves' age. A specific log-contrast balance formed by Arg, Thr, and Lys was found to be the main driver for lowering serum urea concentrations and increasing calf growth. The use of compositional mixed-effects models identified a cluster formed by the combination of Arg, Thr, and Lys, as a potential AA to optimize calf growth.Peer ReviewedPostprint (published version

Exploring the use of tertiary reclaimed water in dairy cattle production

The objective of this study was to explore through both in vitro and in vivo experiments the use of reclaimed urban wastewater in dairy cattle production systems with the aim of improving water efficiency and sustainability. Firstly, the use of different tertiary treatments (ultrafiltration (UF), ultraviolet disinfection (UV), chlorination process, and their combination) to improve the quality of an urban secondary effluent was studied in intestinal primary cell cultures evaluating the expression of genes related to apoptosis, cell damage, and inflammation. The results revealed that secondary treated wastewater and waters that were treated with a chlorination process (even tap water) caused an increase in apoptosis, intestinal primary cell damage, and inflammation. The in vivo experiment evaluated the short-term effects on health and performance of using UF- and UV-treated secondary effluent compared with the use of tap water for drinking and preparing milk replacer in young calves from 5 to 47 days of age. Calves previously fed with UF + UV treated secondary effluent clearly preferred tap water when they were exposed to a double water choice at the end of the study. This reduction of the palatability and acceptability was probably due to a greater level of water salinity of the treated reclaimed water (570 vs 1437 ± 76.5 μS/cm of conductivity for tap water and UF-UV treated secondary effluent, respectively), which potentially entailed a reduction of calf concentrate intake (466 vs 351 ± 32.2 g/d for calves fed with tap water and UF-UV treated water, respectively). The use of reclaimed water did not pose an acute risk to animal health. It is concluded that improvements on the tertiary treatment to reduce water salinity should be considered when using reclaimed water for drinking purposes in livestock production systems. This study is a first approach to a more sustainable and efficient use of water in animal husbandry for countries with water scarcity. However, more studies are required before its implementation to further study long-term effects and the presence of new-contaminants not defined in the current legislation.info:eu-repo/semantics/acceptedVersio

Quin serà el model ramader dels propers anys del segle actual amb canvi climàtic a Catalunya?

info:eu-repo/semantics/publishedVersio

Age-Related Serum Biochemical Reference Intervals Established for Unweaned Calves and Piglets in the Post-weaning Period

The purpose of the present study is to establish the influence of age on serum biochemistry reference intervals (RIs) for unweaned calves and recently-weaned piglets using large number of animals sampled at different ages from populations under different season trials. Specifically, milk replacer (MR)-fed calves from April–July 2017 (n = 60); from December 2016–March 2017 (n = 76) and from April–August 2018 (n = 57) and one group of healthy weaned piglets (n = 72) were subjected to the study. Serum enzymes and metabolites of calves at age of 24 h (24 h after colostrum intake), 2, 5, and 7 weeks from merged trials and piglets at 0, 7, and 14 days post-weaning (at 21, 28, and 35 days of age) were studied. The main variable is age whereas no major trial- or sex-biased differences were noticed. In calves, ALT, AST, GGT, GPx, SOD, NEFAs, triglycerides, glucose, creatinine, total protein, and urea were greatly elevated (p &lt; 0.001) at 24 h compared with other ages; glucose, creatinine, total protein, and urea constantly decreased through the age; cholesterol's lowest level (p &lt; 0.001) was found in 24 h compared with other ages and the levels of haptoglobin remained unchanged (p &gt; 0.1) during the study. In comparison with the adult RIs, creatinine from 24 h, NEFAs from 2 w, GGT from 5 w, and urea from 7 w are fully comparable with RIs or lie within RIs determined for adult. In piglets, no changes were noticed on glucose (p &gt; 0.1) and haptoglobin (p &gt; 0.1) and there were no major changes on hepatic enzymes (ALT, AST, and GGT), total protein, creatinine and urea even though several statistical differences were noticed on 7 days post-weaning. Cholesterol, triglycerides, NEFAs, cortisol and PigMAP were found increased (p &lt; 0.05) while TNF-alpha was found less concentrated (p &lt; 0.001) at 0 days post-weaning compared with other times. Moreover, the RIs of creatinine and GGT are fully comparable with RIs or lie within RIs determined for adult. In conclusion, clinical biochemistry analytes RIs were established for unweaned calves and recently-weaned piglets and among them some can vary at different ages