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Utilizing different dietary fiber sources has been studied in piglets to help mitigate post-weaning diarrhea and improve post-weaning performance. An experiment was conducted to investigate the effect of adding sugar beet pulp or a stimbiotic (Signis; AB Vista) on nursery pig performance. Barrows (n = 216; average initial BW = 5.1kg) were randomly allotted to one of three dietary treatments and fed a 4 phase feeding program; 1) Control (Con), Insoluble/Soluble fibre ratio (I/S), P1; 4.47, P2; 5.84, P3; 5.82, P4; 7.08. 2) High Soluble (HS) with sugar beet pulp added at 5% (P1 and P2) and 2.5% (P3 and P4) giving the following I/S ratio; P1; 2.63, P2; 2.91, P3; 5.02 and P4; 5.42. 3) Control plus stimbiotic added at 100 g/t (SIG). Pen weight and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Fecal score was visually ranked by pen daily from wean to 35 days. Blanket water medications were not provided. Instead, individual pigs that needed treatment were identified and injected with individual antibiotic interventions, and the number of interventions per pig was recorded. Performance data were submitted to ANOVA using JMP with mean separation by Tukey test and a contingency analysis was used to compare antibiotic injections. At day 14, pigs had a Rotavirus A and B challenge. Addition of HS or SIG reduced (P < 0.05) individual antibiotic treatments by 56 and 32% compared to the CON, respectively. No differences were observed in scour scores or overall ADG. Overall intake was greater (P < 0.01) in HS (0.560 kg) than CON (0.491 kg) or SIG (0.492 kg). Pigs fed SIG (0.671) had a better (P = 0.011) G:F over SBP (0.602), with CON (0.649) being intermediate. In conclusion, HS increased intake where stimbiotic improved feed efficiency, and both decreased antibiotic treatments.

The objective was to determine the influence of feed intake (FI) and fiber source on hindgut disappearance of energy and nutrients in pigs. Ten canulated barrows with an initial body weight (BW) of 38.3 ± 5.4 kg were allotted to a replicated 5 × 4 Latin square design with 5 treatments and 4 periods. A corn-soybean meal-based basal diet (BD) and 2 × 2 factorial treatment arrangement with 2 amounts of FI (9.0 and 4.5% × BW0.75) and 2 fiber sources of sugar beet pulp (SBP) and corn cob were used. Three diets were 1) a BD, 2) a diet replacing 30% of corn and soybean meal in BD with SBP as a source of soluble dietary fiber (SDF), and 3) a diet replacing 15% of corn and soybean meal in BD with corn cobs as a source of insoluble dietary fiber (IDF) to obtain a similar IDF concentration as in the SBP diet. Each period consisted of 7-d adaptation, 2-d fecal collection, and 2-d ileal collection. Apparent ileal digestibility (AID) of energy, dry matter (DM), organic matter (OM), and crude protein (CP) in SBP diet was less (P < 0.001) than that in corn cob diet, whereas AID of neutral detergent fiber in SBP were greater (P < 0.001) than in corn cob diet. Hindgut disappearance of energy, DM, OM, neutral detergent fiber, and acid detergent fiber in SBP diet was greater (P < 0.05) than that in corn cob diet. However, no interaction between FI and fiber source on the AID, apparent total tract digestibility, and hindgut disappearance of nutrients was observed. Overall, hindgut disappearance of nutrients in sugar beet pulp diet was greater than that in corn cob diet. However, the influence of feed intake or the interaction between feed intake and fiber source was not observed.

Lignocellulose is an alternative fiber source for dogs; however, it has not yet been studied as a feed ingredient for the nutrition of dogs. Eight adult Beagles were involved in the study, which consisted of 3 feeding periods of 8 to 12 wk each. All dogs received 3 different diets, which either had the same concentration of fiber sources (2.7% sugar beet pulp or lignocellulose) or were formulated for a similar concentration of approximately 3% crude fiber: 12% sugar beet pulp (highSBP; 3.1% crude fiber), 2.7% sugar beet pulp (lowSBP; 0.96% crude fiber), or 2.7% lignocellulose (LC; 2.4% crude fiber). Feces samples were collected at the end of each feeding period, and the apparent nutrient digestibility, daily amount, and DM content of feces and fecal cell numbers of relevant bacteria were analyzed. The daily feces amount was lower and the feces DM was higher when dogs were fed the LC diet and the lowSBP diet compared with the highSBP diet ( < 0.001). Apparent digestibility of CP, Na, and K was highest with the lowSBP diet followed by the LC and highSBP diets ( < 0.001). After feeding LC, the bacterial cell counts of spp., spp., and the cluster were reduced compared with feeding highSBP and even more reduced after feeding lowSBP ( < 0.001). The bacterial cell count of the cluster was lower in LC and lowSBP compared with highSBP ( < 0.001). The feces of dogs fed LC and lowSBP had lower concentrations of acetate ( < 0.001), propionate ( < 0.001), -butyrate ( = 0.015), total fatty acids ( < 0.001), and lactate ( < 0.001) compared with dogs fed highSBP. The concentration of -butyrate was higher in the feces of dogs fed with LC compared with dogs fed high and low sugar beet pulp (SBP; < 0.001). The pH of the feces of the LC-fed dogs was highest followed by lowSBP- and highSBP-fed dogs ( < 0.001). Depending on the concentration, the use of LC and SBP as fiber sources in dog feed has different impacts on the fecal microbiota and the apparent digestibility of nutrients. Therefore, different areas of application should be considered.

Two experiments were conducted to study the effects of inclusion of additional fiber in the Phase I diet on growth performance and nutrient digestibility in piglets reared under "optimal" or "poor" hygienic conditions. In both experiments, the design was completely randomized with a control diet that contained 2.2% crude fiber and 8 additional isonutritive diets that included 2.5 or 5.0% of sugar beet pulp (SBP), straw, oat hulls (OH), or wheat middlings (WHM). Preplanned polynomial contrasts were used to study the effects of 1) fiber inclusion (control diet vs. average of the 8 fiber-containing diets), 2) source of fiber, 3) level of fiber, and 4) interaction between source and level of fiber. In Exp. 1 (clean barn), fiber inclusion increased ( < 0.01) the incidence of postweaning diarrhea (PWD) and reduced ( < 0.05) feed efficiency and apparent total tract digestibility (ATTD) of all nutrients except that of CP, which was not affected. Piglet performance was not affected by source or level of dietary fiber. The ATTD of all nutrients decreased ( < 0.05) as the level of fiber increased and was lower in pigs fed straw or OH than in pigs fed SBP or WHM. The apparent ileal digestibility of GE and DM decreased ( < 0.05) with fiber inclusion, a reduction that was more pronounced ( < 0.05) with straw or SBP than with OH inclusion, with WHM inclusion being intermediate. Fiber inclusion did not affect villous height to crypt depth ratio of the ileum mucosa. The inclusion of 5% of a fiber source increased and counts in the cecum ( < 0.001) but the to ratio was not affected. In Exp. 2 (dirty barn), fiber inclusion did not affect piglet performance but tended to increase PWD ( = 0.07). Also, fiber inclusion reduced ( < 0.05) the ATTD of all dietary components except that of CP, which was not affected. Source and level of fiber did not affect ATTD of nutrients except for DM, which was greater for pigs fed SBP than for pigs fed straw ( < 0.05). In conclusion, in the current research, pigs reared under optimal hygienic conditions had lower incidence of PWD, better growth performance, and greater DM and GE digestibility than pigs reared under poor hygienic conditions. An excess of dietary fiber was more detrimental for all these traits in piglets reared under optimal hygienic conditions. The effects of the source and level of fiber on piglet performance was limited in the 2 experiments.

Dehydrated citrus pulp (DCP) contains limiting amount of nitrogen (N) and phosphorus (P), probably due to the high content of fiber components and phytic acid. The use of fibrolytic enzymatic complexes could favor the use of DCP in piglets’ diets. Thus, the objective of this work was to determine the balance of P and N in weaned piglets fed diets with increasing levels of DCP, with or without the addition of exogenous enzymes. Forty castrated male piglets with average initial weight of 7.85 ± 1.64 kg were individually distributed in metabolic cages, in a factorial scheme (2x4): with or without exogenous enzymatic complex (carbohydrases + phytase) X levels of DCP inclusion (0, 3, 6 and 9%) to the diets, with five replicates per treatment and one animal per experimental unit. Diets were formulated based on corn, soybean meal, powdered milk, powdered whey, sugar, soybean oil, amino acids, vitamins, minerals and additives. Experimental diets were provided for 12 d with the initial 7 d being the adaptation period. Ferric oxide (Fe2O3) was added as an indigestible marker on d 7 and 11, respectively. P and N in diets, feces and urine were determined for P and N balance calculation. There was no interaction (P> 0.05) between the addition of enzymes and the levels of DCP. However, there was a reduction (P= 0.067) of P excreted in the feces by the addition of enzymes, as well as a reduction (P= 0.028) of N excreted in the feces. Increasing DCP levels in diets resulted in a linear increase (P= 0.046) of N excreted in feces and a linear reduction (P= 0.038) of N absorbed. The addition of exogenous enzymes (carbohydrases and phytase) in diets for weaned piglets reduces fecal excretion of P and N, while DCP inclusion increases the N excretion in feces.

Since the 1990s, the impact of late gestational nutrition and management on lactation and reproduction has become the focus of dairy management. Transition cow management has been credited with having greater influence on herd performance as compared to previous focus on lactation nutrition. Several seminal papers published in 1990s and early 2000s directed management practices of dry cows, rightly or wrongly, toward critical factors impacting calving and lactation. Dairy cow gestational protein requirements cited a 1956 study on Red Danish cows until Bell (1995) characterized the modern Holstein fetus’ chemical composition over the last 70 days of gestation. Recognized health effects of “fat cow syndrome”, similarly described for pigs, focuses late pregnant dairy cow management on body condition management starting in late lactation. Optimum condition was emphasized, recognizing negative impacts of excessive limited BC on lactation and reproduction. Maximizing dry matter intake was a nutritional goal for preventing energy-based metabolic challenges, until research indicated excessive energy during early, non-lactating period was more critical to managing postpartum metabolic derangements than the weeks prior to calving; which is like controlling energy intake of sows. Delivery of amino acids, estimated by metabolizable protein intake, has recently earned focus of research, relative to immune function, metabolic stability and reproductive success during early lactation. Identifying amino acids as critical fetal metabolic fuel, and consequences of excessive maternal protein mobilization, has become a focal point of swine and dairy transition nutrition. Although management of the transition cow has been greatly refined through nutritional research, improved cow performance has not yet been realized in the field. Recognition of the interplay between nutrition, environment and management relative to enhancing cow behavior has provided insight to the challenges of managing the transition cow. Metabolic, environmental and management challenges facing the physiologic transition from pregnancy into lactation occur in all production species. Although cows and sows procure essential nutrients by different digestive modes, cross-species applications can provide new or reinforcing perspectives on collective management approaches.

Improving the traits that underlie meat quality is a major challenge in the beef industry. The objective of this paper was to detect QTL linked to sensory meat quality traits in 3 French beef cattle breeds. We genotyped 1,059, 1,219, and 947 young bulls and their sires belonging to the Charolais, Limousin, and Blonde d'Aquitaine breeds, respectively, using the Illumina BovineSNP50 BeadChip (Illumina Inc., San Diego, CA). After estimating relevant genetic parameters using VCE software, we performed a linkage disequilibrium and linkage analysis on 4 meat traits: intramuscular fat content, muscle lightness, shear force, and tenderness score. Heritability coefficients largely ranged between 0.10 and 0.24; however, they reached a maximum of 0.44 and 0.50 for intramuscular fat content and tenderness score, respectively, in the Charolais breed. The 2 meat texture traits, shear force and tenderness score, were strongly genetically correlated (-0.91 in the Charolais and Limousin breed and -0.86 in the Blonde d'Aquitaine breed), indicating that they are 2 different measures of approximately the same trait. The genetic correlation between tenderness and intramuscular fat content differed across breeds. Using a significance threshold of 5 × 10(-4) for QTL detection, we found more than 200 significant positions across the 29 autosomal chromosomes for the 4 traits in the Charolais and Blonde d'Aquitaine breeds; in contrast, there were only 78 significant positions in the Limousin breed. Few QTL were common across breeds. We detected QTL for intramuscular fat content located near the myostatin gene in the Charolais and Blonde d'Aquitaine breeds. No mutation in this gene has been reported for the Blonde d'Aquitaine breed; therefore, it suggests that an unknown mutation could be segregating in this breed. We confirmed that, in certain breeds, markers in the calpastatin and calpain 1 gene regions affect tenderness. We also found new QTL as several QTL on chromosome 3 that are significantly associated with meat tenderness in the Blonde d'Aquitaine breed. Overall, these results greatly contribute to the goal of building a panel of markers that can be used to select animals of high meat quality.

This paper reports genetic parameters for lamb survival and mortality traits on sheep farms in New Zealand. Lamb survival and mortality records were obtained from 38 flocks (103,357 lambs) from 5 yr of lambing data (2007 to 2011) and include many breeds and their crosses (predominantly Romney, Perendale, Coopworth, and Texel). A number of models were tested, all including environmental weather effects and investigating the random environmental effect of dam and litter (dam/year) as well as logit transformation for binary traits. Total heritability (direct + maternal) estimates were low for lamb viability at birth (0.01), lamb death risk to dystocia (0.01), and lamb death risk to starvation exposure (0.01) from birth to 3 d of age in an analysis accounting for direct and maternal genetic effects and the maternal environmental effects. Lamb survival heritabilities reported are very low (total heritabilities range from 0.02 to 0.06). The total heritabilities for the lamb death risk traits are lower than reported estimates of survival to 3 d of age or to weaning suggesting selection for the postmortem traits are not warranted at this time within these flocks. The total heritability for lamb birth weight was moderate (0.38) and the genetic correlations with the lamb death risk traits suggested that directional selection on lamb birth weight would have an effect on survival, although it is likely to have a nonlinear effect and therefore an optimum birth weight at which survival is maximized. This study has also shown that the total heritabilities may be overestimated when not accounting for maternal genetic and environment effects and in particular not accounting for the random environmental effect of litter (dam/year).

The hypothesis tested in this paper is that double-muscled (DBM) and conventional cattle, considerably differing in body composition, have similar NE requirements when: a) NE(m) is scaled as a function of current (P(i)) and adult (P(m)) protein mass; and b) ME for gain (ME(g)) is estimated from protein (Pr) and lipid (Lr) retention and their partial ME use efficiencies, the k(p) and k(l) values, respectively. First, 2 databases were examined: 1 was developed combining well known literature information from comparative slaughter trials conducted on British beef steers; the other was based on a trial conducted using extremely lean DBM Piemontese bulls. From the first database, NE(m) was calculated to be 1.625 × P(i) ÷ P(m) × P(m)(0.73) (MJ/kg(0.73)). From the second database, the daily ME(g) was determined as 22.8 MJ × Pr ÷ k(p) + 38.74 MJ × Lr ÷ k(l), assuming (from prior reports) that k(p) = 0.20 and k(l) = 0.75. Thereafter, ME(m) was defined as ME intake minus ME(g), and, hence, NE(m) was predicted as 1.625 × P(i) ÷ P(m) × P(m)(0.73) (where 1.625 was the value obtained from the first dataset). The resulting k(m) (NE(m)/ME(m)) averaged 0.67. This k(m) value did not differ from that (0.65; P = 0.12) predicted by Garrett's equation, which uses dietary ME content as the only predictive variable. Second, the procedure was tested for the ability to detect effects on k(m) caused by increasing BW and dietary factors not estimable from the dietary ME content only. Data were gathered from a trial involving 48 DBM Piemontese bulls divided into 4 groups fed 1 of 4 diets differing in CP content (145 or 108 g/kg DM), with or without addition of 80 g/d of rumen-protected CLA (rpCLA). Bulls were examined at 3 consecutive periods of growth, corresponding to 365, 512 and 631 kg of average BW. All energy balance items were influenced by increasing BW, except k(m) (P = 0.61), in agreement with the expectation that NE(m) requirement depends on the degree of maturity (P(i)/P(m)) and the P(m)(0.73) of an animal, whereas k(m) reflects characteristics of the feed provided. The k(m) value was also influenced by the CP × rpCLA interaction (P = 0.013). We conclude that DBM and British beef steers have similar NE requirements when these are scaled as a function of P(i) and P(m), and gain composition, considering Pr, k(p), Lr and k(l). The proposed procedure will be useful to predict the energy requirements and feed use in cattle of different types that vary in BW, provided that body and gain compositions are known or accurately predicted.

The aim of this work was to evaluate the correlated responses on survival rates after 10 gen- erations of selection for ovulation rate (OR). Selection was based on the phenotypic value of ovulation rate estimated at d 12 of second gestation by laparoscopy. Traits recorded were litter size (LS), estimated as total number of rabbits born per litter in up to 5 parities; OR, estimated as the number of corpora lutea in both ovaries; the number of implanted embryos (IE), esti- mated as the number of implantation sites; the number of right and left IE (RIE and LIE); ovulatory difference (OD), defined as the difference between the right and the left OR, expressed as an absolute value; implanta- tory difference (ID), defined as the difference between RIE and LIE, expressed as an absolute value; embryonic survival (ES), calculated as IE/OR; fetal survival (FS), calculated as LS/IE; prenatal survival (PS), calculated as LS/OR. A total of 1,081 records were used to analyze ES, and 770 were used to analyze FS and PS. The num- ber of records used to analyze the other traits ranged from 1,079 for ID to 3,031 for LS. Data were analyzed using Bayesian methodology. Genetic parameters of OR, OD, and LS were estimated in a previous paper. Estimated heritabilities of IE, ID, ES, FS, and PS were 0.11, 0.03, 0.09, 0.24, and 0.14, respectively. Estimated repeatabilities of IE, ID, and ES were 0.22, 0.12, and 0.20. Estimated phenotypic correlations of OR with ES, FS, and PS were −0.07, −0.26, and −0.28, respectively. Their estimated genetic correlations with FS and PS were negative (probability of being negative 1.00 and 0.98, respectively). Nothing can be said about the sign of the genetic correlation between OR and ES. Ovu- lation rate was phenotypically uncorrelated with ID. Their estimated genetic correlation was positive (prob- ability of being positive 0.91). The genetic correlation of ID with PS and LS was not accurately estimated. Phenotypic and genetic correlations between LS and survival rates were positive (probability of being posi- tive 1.00). In 10 generations of selection, FS decreased around 1% per generation. No correlated response in ES was observed. In summary, the decrease in FS in rabbits selected for OR seemed to be responsible for the lack of correlated response observed in LS.

Environmental effects of excess P from manure and the soaring price of phosphates are major issues in pig production. To optimize P utilization, it is crucial to improve our capacity to predict the amount of P absorbed, while taking into account the main factors of variation. Mathematical modeling can represent the complexity of the processes and interactions in determining the digestive utilization of P in growing pigs. This paper describes and evaluates a model developed to simulate the fate of the dietary forms of P in the digestive tract of growing pigs, with particular emphasis on the effect of dietary Ca and exogenous phytase on P digestive utilization. The model consists of 3 compartments associated with specific anatomical sections: stomach, proximal small intestine, and distal small intestine. The main metabolic processes occurring in these sections are, respectively, P solubilization/insolubilization and phytate P hydrolysis, and P absorption and P insolubilization. Model parameters governing these flows were derived from in vitro and in vivo literature data. The sensitivity analysis revealed that the model was stable within a large range of model parameter values (±1.5 SD). The model was able to predict the efficacy of Aspergillus niger microbial phytase in accordance with literature values, as well as the decreased efficacy of plant phytase compared with microbial phytase. The prediction capabilities of the model were assessed by comparing actual and simulated P and Ca apparent total-tract digestibility (ATTD) based on published pig data not used for model development. Prediction of P digestibility across 66 experiments and 281 observations was adequate [P ATTD observed = 0.24 (SE, 0.943) + 0.98 (SE, 0.0196) × P ATTD predicted; R(2), 0.90; disturbance error (ED), 96.5%], whereas prediction of Ca digestibility across 47 experiments and 193 observations was less accurate (Ca ATTD observed = 11.1 + 0.75 × Ca ATTD predicted; R(2), 0.78; ED, 20.4%). A lack of agreement between experimental and simulated Ca digestibility was found. This model is, therefore, useful in evaluating P digestibility for different feedstuffs and feeding strategies. It can also be used to provide insight for improving dietary P utilization, especially from plant sources, by quantifying the effect of the mean sources of variation affecting P utilization.

Recent advances in on-farm technology now provide us with multiple time-series of reliably measured indicators of animal performance and status at the level of the individual. This paper presents a smoothing approach for extracting biologically meaningful features from such time series using bovine milk yield data as an example. The main goal of this study was to illustrate how the method can be used to detect production deviations, extract quantifiable features of the deviation profiles, and thus provide means to examine hypotheses concerning the nature of the deviations. The effectiveness of the method was assessed with complete lactation curves from 47 Holstein cows. Within their lactations, the cows were each subjected to 1 nutritional challenge for a period of 4 d (their standard diet: a maize silage-based total mixed ration was diluted with 60% wheat straw), which provoked a decline in the milk yield in all cows. The challenge was imposed between the same calendar days for all cows. Thus, the cows were at different stages of lactation: early (n = 14), mid (n = 15), and late (n = 18). Each milk-yield curve was decomposed into components that capture the short-term deviations of the cow such as the response to the nutritional challenge and describe the phenotypic potential yield function of that cow throughout its lactation. The difference between the 2 components gives a measure of the milk loss. In all, 480 deviations were detected from the complete lactations of 47 cows. The milk loss provoked by the feeding challenge (n = 47) was significantly related to the milk yield immediately before the challenge (r = 0.86, P 0.1) to the relationship between the ratio (rate of recovery/milk loss) and days from calving, indicating that the force of recovery was unaffected by stage of lactation. These results suggest that differential smoothing can be a useful tool for quantifying biological disturbances in animal performance and for extracting features that relate to the potential and robustness of an animal.

Recent data suggest morbidity and mortality are increasing in feedlot cattle, primarily due to bovine respiratory disease. It is well documented that disease challenges in beef cattle result in reduced gain, efficiency and HCW in cattle fed to the same DOF. Typically, diseased animals produce carcasses with less desirable quality grades due to reduced marbling scores. More recent data suggest that although diseased animals can be fed to similar fat-thickness endpoints with added DOF, carcass weights and marbling scores are still reduced compared to non-treated contemporaries. Of note, non-treated animals with lung lesions also showed marked reductions in performance, indicating subclinical disease. While the bovine immune response to infectious disease challenge is complex, the acute inflammatory response typically results in the production of acute phase proteins and pro-inflammatory cytokines from the liver. New data suggest that respiratory disease in cattle, as indicated by lung palpation at slaughter, could be related to the presence of 1 or more liver abscesses. Disease increases the animal’s maintenance energy requirements, resulting in less energy available for growth, increased production costs and lower gross revenue. Today, the majority of fed cattle are marketed on a carcass basis (grid or dressed), with HCW accounting for over 80% of the variation in gross revenue from individual animals. These economic factors make disease, and more specifically bovine respiratory disease, a costly challenge for beef production. The objective of this paper is to review the impacts of disease on growth and carcass characteristics, evaluate a large population database to evaluate trends in commercial production, and highlight potential relationships between other diseases experienced in feedlot beef production.

The objective of this study is to build energy models for predicting nitrogen-corrected apparent metabolizable energy (AMEn) requirements of different categories of Chinese Yellow broiler breeder hens during egg-laying period. Data for modelling were generated from published research papers, unpublished results from our research group and some production data supplied by compaines. There are dozens of breeds of Chinese Yellow broiler breeders in China, therefore, hens were alloted into 3 categories: heavy, medium and light body weight (BW, kg). We reffered to published articles to determine coefficients of AMEn requirement for maintenance (AMEnm) and gain (AMEng) respectively. The moldels of AMEn for egg production (AMEnp) were built and then daily intake of AMEn (AMEni, kcal/d/hen) models acquired according to factorial approach that AMEni = AMEnm + AMEng +AMEnp. Heavy BW: AMEni = 101 × BW0.75 + 5.33 × average daily gain (ADG, g) + 2.55 × egg mass (EM, g/d/hen) (P < 0.001; R(2) = 0.711); medium BW: AMEni = 101 × BW(0.75) + 5.33 × ADG + 2.94 × EM (P < 0.01; R(2) = 0.586) and light BW: AMEnp = 126 × BW(0.75) + 5.33 × ADG + 1.88 × EM (P < 0.001; R(2) = 0.605). The AMEn requirments (kcal/kg diet) for each category of hens were determined with 2678, 2628 and 2583 kcal/kg for heavy, medium and light BW respectively, which are the mean values of dietary AMEn from many published articles divided into 3 categories accordingly. The AMEni requirements acquired from the models were 348, 303 and 210 kcal/d/hen for heavy, medium and light BW respectively. These models were evaluated by simulation of experiments reported in the literature, and comparison of simulated to measured requirements, which showed that models provided good adjustments. Performance trials will be conducted to further evaluate these models.

The aim of this paper was to estimate the genetic relationships among calving ease (CE), calf survival (CS), and gestation length (GL) to assess the possibility of including this information in beef cattle breeding programs. A total of 35,395 field records were available for CE, 30,684 for GL, and 36,132 for CS from the Asturiana de los Valles beef cattle breed. The 3 traits were analyzed as traits of the calf fitting a multivariate linear mixed model. Estimates of heritability (+/-SE) for the direct genetic effects (CEd, GLd, and CSd) were 0.325 +/- 0.022, 0.331 +/- 0.026, and 0.226 +/- 0.018, respectively, whereas the estimates for maternal genetic effects (CEm, GLm, and CSm) were 0.066 +/- 0.018, 0.066 +/- 0.017, and 0.034 +/- 0.011. The estimates for the ratio of permanent environmental variance to phenotypic variance were CEc 0.090 +/- 0.011, GLc 0.066 +/- 0.011, and CSc 0.024 +/- 0.007. Genetic correlations between direct, maternal genetic, or permanent environmental effects involving CE and GL were, in general, positive and moderate, whereas those involving CE and CS were high. All were significant except for the pair CEm-GLm (0.277 +/- 0.172). Correlations between GL and CS were nonsignificant. Genetic correlations for CEd-CEm, GLd-GLm, and CSd-CSm were negative and high, ranging from -0.461 +/- 0.120 for GLd-GLm to -0.821 +/- 0.145 for CSd-CSm. The genetic correlations for CEd-CSm and for CSd-CEm were negative, significant, and high, whereas that for GLd-CEm was moderate (-0.323 +/- 0.124) and that for GLd-CSm was nonsignificant. The genetic correlations for GLm with the direct effects of the other traits were non-significant. Strong selection for CE will result in a significant correlated response in CS. Therefore, CE can be considered an early indicator of CS performance. The benefit of using GL as a correlated trait in a genetic evaluation with CE and CS seems limited.

This paper aims to compare different adaptive responses of the mammary gland of cows, ewes, and goats submitted to extended milking intervals in different systems of management. Depending on the species, these extended milking intervals can be characterized by the following milk removal approaches; 3 milkings every 2 d, elimination of 1 milking per week (i.e., 13 vs. 14 milkings per week), and once-daily milking with additional suckling (i.e., dual purpose system of suckling and milking) or without suckling (exclusive once-daily milking). All the high-yielding animals and breeds adapted without problems to being submitted to intervals between milking less than 20 to 21 h. Under these conditions, all ruminant species demonstrated only low and transitory variations in milk production and quality. Thus, management systems using such an interval are good tools for the dairy producer who wants to save time without important adverse economic impact. When animals have good mammary gland health, these management systems can be applied without preliminary adaptation. However, goats and some breeds of dairy ewes seem to adapt to once-daily milking better than cows. Additionally, goats and ewes with higher production levels demonstrate a lower reduction in milk yield. With goats, there is only a limited variation in milk quality and cheese-making capacity of the milk produced, but ewes and cows show a significant enrichment of milk constituents, especially in fat. This indicates some differences in the regulation of lactose, protein, and fat synthesis depending on the duration of the milking interval and provides interesting models for physiological studies on milk secretion and synthesis regulation. Anatomical and physiological characteristics of lactating cows and ewes, in terms of cisternal vs. alveolar volumes within the mammary glands, could contribute to different abilities in adaptation to different milking systems. In goats, however, other mechanisms, such as compliancy of the mammary gland and regulation of tight junction impermeability, could be involved in milk secretion regulation and, thus, could become new targets for genetic selection of animals better adapted to accept extended milking intervals.

Adjustment factors to allow comparison of EPD from several breed associations for birth, weaning, and yearling weights have been available for more than 10 yr. This paper describes steps to calculate adjustment factors for EPD for 4 carcass traits: marbling score, fat thickness, ribeye area, and retail product percentage. The required information is the same as for the weight traits: 1) breed of sire solutions based on measurements on progeny at the US Meat Animal Research Center (USMARC) that have sires with breed association EPD, 2) mean EPD of sires weighted by number of progeny at USMARC (USMARC progeny not included in breed association EPD), and 3) mean EPD of nonparents from breed associations (defined as animals born 2 yr prior to calculation of EPD). Records at USM-ARC are adjusted to 100% heterozygosity because the purpose of the adjustment factors is to allow prediction of performance of progeny of sires mated to other breeds of dam. A critical step is to adjust breed of sire solutions, which are based on an earlier sample of sires, to the equivalent of a sample from a more recent nonparent group using the difference between mean EPD from information sources 2) and 3). The difference is multiplied by the coefficient of regression of USMARC progeny on EPD of their sires. With weight traits, these coefficients are not greatly different from unity. With the carcass traits, 2 sets of coefficients can be used depending on whether the EPD are based on carcass or ultrasound measurements. The regression coefficients also reflect differences in conditions for USMARC progeny (all steers) and factors associated with breed association EPD. Only for marbling score and ribeye area were any estimates of the regression coefficients near unity. For other traits, the coefficients ranged from 1.65 to 2.82. The solutions for breed of sire, differences in mean EPD, and regression coefficients are then used to calculate adjustment factors for EPD of 11 breeds including the arbitrary base breed, Angus.

The aim of this paper was to estimate direct and maternal genetic parameters for calving ease (CE), birth weight (BrW), weaning weight (WW), and calving interval (CI) to assess the possibility of including this information in beef cattle improvement programs. Field data, including a total of 59,813 animals (1,390 sires and 1,147 maternal grand sires) from the Asturiana de los Valles beef cattle breed, were analyzed with a multivariate linear model. Estimates of heritability for direct genetic effects (CED, CID, BrWD, and WWD) were 0.191 +/- 0.019, 0.121 +/- 0.013, 0.390 +/- 0.030, and 0.453 +/- 0.035, respectively, whereas those for maternal genetic effects (CEM, BrWM, and WWM) were 0.140 +/- 0.015, 0.208 +/- 0.020, and 0.138 +/- 0.022, respectively. Genetic correlations between direct or maternal genetic effects across traits were, in general, positive and moderate to low. However, genetic correlation for the pair CED-BrWD was positive and high (0.604 +/- 0.064). Genetic correlations between the direct and maternal genetic effects within a trait were negative and moderate (-0.219 +/- 0.097 for CE, -0.337 +/- 0.080 for BrW, and -0.440 +/- 0.102 for WW). Genetic correlations for CED-BrWM and CED-WWM were -0.121 +/- 0.090 and -0.097 +/- 0.113, respectively. The genetic correlation for CEM-CID was unfavorable (0.485 +/- 0.078), and those for CEM-BrWD (-0.094 +/- 0.079) and CEM-WWD (-0.125 +/- 0.082) were low and negative. The genetic correlation between CID and WWM was favorable (-0.148 +/- 0.106). Overall, the data presented here support the hypothesis that maternal effects for CE and BrW are not the same and that the genetic relationships between CI and maternal effects for WW in beef cattle follow a similar pattern to that reported between CI and milk yield in dairy cattle. Moreover, the need to include direct and maternal breeding values in beef cattle selection programs is suggested.

This paper reports estimates of correlated genetic change in reproductive performance of purebred gilts producing two-way cross litters and purebred sows producing purebred litters as well as postweaning performance of two-way cross and purebred pigs produced during reciprocal recurrent selection (RRS) between Line 8 (Duroc) and Line 9 (Beltsville No. 1) for 21-d litter weight production of crossbred gilts. A randomly mated control line developed from a crossbred foundation was maintained to monitor environmental change. Data were adjusted for age of dam, inbreeding of dam, inbreeding of litter (or pig) and linear and quadratic effects of day born within season. The traits evaluated were: litter size, litter weight and average pig weight/litter at birth and weaning (42 d); postweaning average daily gain; age at 90.7 kg and backfat thickness at 90.7 kg. Two data sets were analyzed; the first set included seven seasons of data with purebred gilts producing two-way cross litters, and the second set included seven seasons of data with purebred sows producing purebred litters. No estimates of environmental trend were significant in either set of data. In the first data set, only the estimate of genetic change in backfat thickness of two-way cross pigs was significant and it was in the desired direction. All other estimates were small and did not approach significance. In the second data set, estimates of genetic trend were greater in Line 9 than in Line 8.(ABSTRACT TRUNCATED AT 250 WORDS)

SUMMARY This study involved the records of 339 purebred Duroc, Hampshire and Yorkshire gilts and 192 two-breed cross gilts resulting from matings among the three breeds. The primary purpose of this paper was to investigate the relationship of prebreeding traits, including the growth of the gilt and her littermates, with subsequent measures of reproduction. Heritabilities were estimated for several traits and in general the estimates were somewhat higher than most estimates in the literature. Genetically, all measures of growth were favorably and moderately to highly correlated to ovulation rate, with the relationship being stronger for traits measured late in growth as compared to traits measured early in growth. The only traits that had large genetic correlations with number of corpora lutea per embryo were birth weight (rg=-.90) and weaning weight (rg=.91). None of the phenotypic correlations between prebreeding traits and reproductive traits were large and only eight of the 68 correlations were significant. Gilts which grew faster, were younger at 100 kg, were heavier at breeding and had more days from 100 kg to breeding also had higher ovulation rates. Gilts which were heavier and older ~tt breeding and had more days from 100 kg to breeding also had more embryos.

Components of variance are estimated for the three-way classification analysis of variance of DHIA reported first and second milk and fat records of artificially sired Holstein cows and of Owner-Sampler reported milk and fat records of artificially sired Holstein cows. The total variance of milk and fat records is partitioned into the following components with the approximate percent of total variance: sire, 6%; year-season, 2%; herd, 30%; sire by year-season, 0%; sire by herd, 1–2%; herd by year-season, 6–8%; sire by herd by year-season, 1–7%; and residual, 50%. Copyright © 1961 American Society of Animal Science. Used by permission. C O M P O N E N T S O F V A R I A N C E A S S O C I A T E D W I T H M I L K A N D F A T R E C O R D S O F A R T I F I C I A L L Y S I R E D H O L S T E I N D A U G H T E R S L. D. VANVLECK, L. H. WADELL, AND C. R. HENDERSON Cornell University, Ithaca, New York C OMPONENTS of variance have been used widely in genetic and animal breeding applications. Some earlier reports of these techniques were by Lush et al. (1934), Bywaters (1937), Stonaker and Lush (1942), and Baker et al. (1943). Important animal breeding applications of variance component estimates are: (1) to predict the breeding values of sires or dams and to predict real producing abilities of cows, (2) to indicate sources of variation which should be considered in analyzing production records, (3) to aid in the establishment of progeny testing programs, including design of the test, number of progeny required, and effectiveness of such programs, and (4) to direct attention to sources of genetic by genetic, genetic by environmental, and environmental by environmental interactions which should be considered in the above programs. The purpose of this paper is to present estimates of sire, herd, year-season, and interaction components of variance for first and second milk and fat DHIA records and OwnerSampler milk and fat records of artificially sired (AI) Holstein daughters.

In the dairy cow, negative energy balance affects milk yield and composition as well as animal health. Studying the effects of negative energy balance on dairy cow milk production is thus essential. Feed restriction (FR) experiments attempting to reproduce negative energy balance by reducing the quantity or quality of the diet were conducted in order to better describe the animal physiology changes. The study of FR is also of interest since with climate change issues, cows may be increasingly faced with periods of drought leading to a shortage of forages. The aim of this article is to review the effects of FR during lactation in dairy cows to obtain a better understanding of metabolism changes and how it affects mammary gland activity and milk production and composition. A total of 41 papers studying FR in lactating cows were used to investigate physiological changes induced by these protocols. FR protocols affect the entire animal metabolism as indicated by changes in blood metabolites such as a decrease in glucose concentration and an increase in non-esterified fatty acid or β-hydroxybutyrate concentrations; hormonal regulations such as a decrease in insulin and insulin-like growth factor I or an increase in growth hormone concentrations. These variations indicated a mobilization of body reserve in most studies. FR also affects mammary gland activity through changes in gene expression and could affect mammary cell turnover through cell apoptosis, cell proliferation, and exfoliation of mammary epithelial cells into milk. Because of modifications of the mammary gland and general metabolism, FR decreases milk production and can affect milk composition with decreased lactose and protein concentrations and increased fat concentration. These effects, however, can vary widely depending on the type of restriction, its duration and intensity, or the stage of lactation in which it takes place. Finally, to avoid yield loss and metabolic disorders, it is important to identify reliable biomarkers to monitor energy balance.

Precision feeding (PF) with the daily mixing of 2 diets with different lysine content (high (H) or low (L)) was previously reported for growing pigs to reduce protein intake and N excretion compared with a conventional feeding (CF) based on a single diet (C). Using a simulation approach based on farm data, the objective of the present paper was to describe and evaluate a decision support system for the PF of gestating sows allowing the daily distribution of a tailored ration to each sow. Two datasets, 1 of 2,511 gestations (farm A) and 1 of 2,528 gestations (farm B), reporting sows’ characteristics at insemination and objectives at farrowing were used as inputs for a Python model. This model, mainly based on InraPorc, calculates the nutrient requirements of each sow over gestation and simulates the impact of PF in comparison to CF. Simulated diets L, H, and C contained 3.0, 6.5, and 4.8 g/kg of standardized ileal digestible lysine (SID Lys) and 2.0, 3.3, and 2.5 g/kg of standardized total tract digestible phosphorus (STTD-P), respectively. The influence of farm, parity, gestation week, and their interactions, on calculated SID Lys and STTD-P requirements was analyzed applying a mixed model. The calculated SID Lys and STTD-P requirements increased markedly in the last third of gestation (P < 0.01) and were higher for primiparous than for multiparous sows, unless after week 14 for STTD-P requirement. The calculated SID AA and mineral requirements were lower for farm B than farm A (respectively, 2.94 vs. 3.08 g/kg for SID Lys and 1.30 vs. 1.35 g/kg for STTD-P, P < 0.01). On average, feed L represented 86% and 92% of the feed projected to be delivered by the PF strategy in farms A and B, respectively. Compared to CF, average calculated dietary SID Lys content was lowered by 27% and 32% with PF, for farms A and B, respectively, while average calculated dietary phosphorus content was lowered by 13% and 16%. The simulated proportions of sows in excess and deficient in SID Lys were reduced with PF. Compared to CF, the PF strategy allowed for a 3.6% reduction in simulated feed cost per sow during gestation, and reduced nitrogen and phosphorus intake (by 11.0% and 13.8%, respectively) and excretion (by 16.7% and 15.4%, respectively). To conclude, these simulations indicate that PF of gestating sow appears to be relevant to meet the amino acid requirement while reducing feed cost, and supplies and excretion of nitrogen and phosphorus.