Levels Of Feed Restriction Research Articles

Feed restriction of F1 Holstein × Zebu cows in the final third of lactation modifies intake, nutrient digestibility, feeding behavior, and performance

ABSTRACT The objective of this study was to evaluate the effect of quantitative feed restriction level on nutrient intake and digestibility, nitrogen balance, efficiency and feeding behavior, and productive performance of F1 Holstein × Zebu cows in late lactation. Sixty F1 Holstein × Zebu cows were used at the stage of late lactation (183.0±17.5 days of lactation) and with initial body weight (BW) of 499±30 kg. The experimental arrangement adopted was the completely randomized design, with five feed restriction levels [...]

Feed quantitative restriction and coenzyme Q10 level on performance, plasma lipoproteins and organ weights of broiler chicks

An experiment was conduct in order to investigate the effects of feed restriction level and duration and dietary coenzyme Q10 level on growth performance, organ characteristics and plasma lipoproteins. A factorial arangment based on a completely randomized design was performed using two levels of feed restriction (10 and 20% less than the standard Ross strain 308 guidelines), two levels of restriction duration (7 and 14 days) and three levels of coenzyme Q10 (0, 20 and 40 mg/kg feed). The results of the experiment showed that restriction intensity had significant effect on feed intake in first, second and sixth weeks of age (P<0.05), body weight gain in second and sixth weeks of age (P<0.05), and feed conversion ratio in first week of age (P<0.05). Restriction duration had significant effect on feed intake in third week of age (P<0.05), and feed conversion ratio in third and sixth weeks of age (P<0.05). Coenzyme Q level had significant effect on feed intake in first and sixth weeks of age (P<0.05), body weight gain in second, fifth and sixth weeks of age (P<0.05), and feed conversion ratio in second and sixth weeks of age (P<0.05). In conclusion, considering the positive effects of feed restriction and coenzyme Q10 on broiler yield, the simaltaneous use of feed restriction strategy and dietary coenzyme Q10 can be considered as a management program in order to improvement of broiler productivity.

Developmental and reproductive characteristics of beef heifers classified by number of estrous cycles experienced by start of first breeding.

A retrospective analysis was conducted to evaluate the effect of number of estrous cycles exhibited before breeding on growth and reproductive performance of replacement beef heifers fed ad-libitum or restricted by 20% less than ad-libitum during postweaning development over a 9-yr period. Progesterone concentration in blood samples collected at 9- to 11-d intervals were used to assign heifers into groups by number of estrous cycles exhibited before the start of breeding: 0 (nonpubertal; n = 395), 1 (n = 205), 2 (n = 211), 3 (n = 116), or >3 (n = 249). Heifers (P < 0.01) in the 0 cycle group were born 6 d later than the 1, 2, or 3 cycle groups, which were born 4 d later (P < 0.01) than the >3 cycle group. Weight of heifers at birth decreased (P < 0.05) as the number of cycles increased. Weaning weight and ultrasound measures of loin area and fat thickness over the loin at 1 yr age increased as the number of cycles increased (P < 0.01). Postwean weight gain, hip height at 1 yr age, and weights from the start of breeding through precalving increased with cycle numbers in a quadratic fashion (P < 0.02) and were greater (P < 0.05) in ad-libitum than restricted-fed heifers. Pregnancy rate in the 0 cycle group was lower (84%; P < 0.05) than the 1 (90%) or >3 (94%) estrous cycles groups and tended to differ (P < 0.1) from the 2 (88%) and 3 (89%) estrous cycle groups. Interval from the start of breeding to calving was 3 to 5 d longer (P < 0.05) for the 0 cycle group (300 ± 1 d) than other groups. Proportion of heifers calving in the first 21 d was less (P < 0.05) in the 0 or 1 cycle groups than other groups. Pregnancy rates of 2-yr-old cows (n = 898) were lowest (P < 0.05) for the 0 (73%) and 2 (79%) estrous cycle groups than the 1 (85%), 3 (90%), or >3 (92%) estrous cycle groups. Restricted level of feeding during postweaning development resulted in greater (P < 0.05) proportion of heifers in 0 cycle group and lower (P < 0.05) proportion in >3 cycle group, but reproductive performance was not influenced (P > 0.1) by level of feeding or interaction of feeding and estrous cycle grouping. In summary, date of birth and rate of physical maturation (weight, height, and fat deposition) were associated with timing of puberty. Pregnancy rate was greater in heifers that exhibited estrus before the start of breeding, but did not improve from having more than one estrous cycle. Proportion conceiving early was greater for heifers having two or more cycles before breeding.

Net protein requirements and metabolizable protein use for growing ram lambs fed diets differing in concentrate level and roughage source

Two trials were conducted to determine net protein requirements and the use of metabolizable protein (MP) for growing ram lambs when fed diets with different concentrate levels and roughage quality. In a comparative slaughter trial, eighty-four ½ Dorper × ½ Santa Inês ram lambs (18.0 ± 3.3 kg of BW) were individually penned and divided into 2 diet groups differing in roughage source: low-quality (sugarcane bagasse) roughage (LQR) or medium-quality (coastcross hay) roughage (MQR). In each group, 7 lambs were randomly selected and slaughtered after a 10 days adaptation period (baseline). Other 21 lambs from each diet group were fed ad libitum and slaughtered at 25, 35, or 45 kg of BW, and the remaining 28 lambs (14 from each diet group) were submitted to 1 of 2 levels of feed restriction (70 or 50% of the ad libitum intake). Body N content and retention were determined. In the second trial, 6 ram lambs (44.3 ± 5.6 kg of BW) were kept in metabolic cages and used in a 6 × 6 Latin square experiment designed to determine N digestibility and microbial N synthesis, and to compute MP supply by the 2 diets and 3 levels of intake. Nitrogen intake and microbial N synthesis were greater for the animals fed the MQR diet than for those fed the LQR diet (P < 0.05). Neither the endogenous and metabolic N losses, nor the net protein requirements for growth differed between diets (P > 0.05). However, the proportion of MP used for both maintenance and growth was lower for the animals fed the MQR diet (P < 0.05), likely because of an excess of MP reaching duodenum of these animals. We concluded that a reduction of the concentrate level in diets for growing ram lambs, achieved by improving the quality of the diet roughage, allows a greater supply of MP and may contribute to reduce diet protein concentration.

Effect of different levels of feed restriction and fish oil fatty acid supplementation on fat deposition by using different techniques, plasma levels and mRNA expression of several adipokines in broiler breeder hens.

BackgroundReproductive hens are subjected to a restricted diet to limit the decline in fertility associated with change in body mass. However, endocrine and tissue responses to diet restriction need to be documented.ObjectiveWe evaluated the effect of different levels of feed restriction, with or without fish oil supplementation, on metabolic parameters and adipokine levels in plasma and metabolic tissues of reproductive hens.MethodsWe designed an in vivo protocol involving 4 groups of hens; RNS: restricted (Rt) unsupplemented, ANS: ad libitum (Ad, receiving an amount of feed 1.7 times greater than animals on the restricted diet) unsupplemented, RS: Rt supplemented, and AS: Ad supplemented. The fish oil supplement was used at 1% of the total diet composition.ResultsHens fed with the Rt diet had a significantly (P < 0.0001) lower growth than Ad hens, while the fish oil supplementation had no effect on these parameters. Furthermore, the bioelectrical impedance analysis (BIA) and the fat ultrasonographic examinations produced similar results to the other methods that required animals to be killed (carcass analysis and weight of adipose tissue). In addition, the Rt diet significantly (P < 0.05) decreased plasma levels of triglycerides, phospholipids, glucose and ADIPOQ, and fish oil supplementation decreased plasma levels of RARRES2. We also showed a positive correlation between insulin values and ADIPOQ or NAMPT or RARRES2 values, and a negative correlation of fat percentage to RARRES2 values. Moreover, the effects of the Rt diet and fish oil supplementation on the mRNA expression depended on the factors tested and the hen age.ConclusionsRt diet and fish oil supplementation are able to modulate metabolic parameters and the expression of adipokines and their receptors in metabolic tissue.

Impact of feed restriction, sexual class and age on the growth, blood metabolites and endocrine responses of hair lambs in a tropical climate

An experiment was conducted to evaluate the effects of feed restriction on the growth, blood metabolites and endocrine responses of hair lambs in a tropical environment. Thirty lambs were distributed in a completely randomized design in a 2×3×3 factorial scheme. Experimentaltreatments consisted of two sexual classes (15 intact males and 15 castrated males, 13.0±1.49kg initial BW and two months old), different levels of quantitative feed restriction (FR) (ad libitum, 300 and 600g/kg) and various ages (14, 19 and 23 weeks). Lamb age influenced the blood leptin (P<0.001), chloride, calcium, phosphorus and magnesium (P<0.05) concentrations. The blood insulin and glucose concentrations (P<0.001) were positively influenced by diet and age. The increased feed restriction resulted in a higher concentration of blood β-hydroxybutyrate (β-HB) (P<0.001). The blood urea nitrogen (BUN) concentration was influenced by diet (P<0.001), age (P<0.001) and the interaction of sexual class and age (P<0.01), with the highest concentrations in the oldest and castrated lambs. A positive correlation was observed between insulin and thyroxine in animals fed ad libitum (P<0.05). The thyroxin is present in low concentrations in the hair lambs raised in a tropical climate. Hair lambs exhibited significant changes in their growth, blood metabolites and endocrine responses, which enabled them to adapt to the feed conditions.

Productive performance, body chemical composition, and deposition of 42-day-old quail for meat subjected to quantitative dietary restriction

This study aimed to assess the effect of quantitative dietary restriction during refeeding on the performance, body chemical composition, and deposition, weight gain of organs and carcass parts of quails reared for meat (Coturnix coturnix coturnix). A total of 144 quails, between 11 to 42 days old, were distributed in a completely randomized design, 4x2 factorial scheme, at four levels of feed restriction (ad libitum, 30%, 50% and 70% restrictions on the daily intake ad libitum) for both genders. Therefore, there was eight treatments with three replicates and six birds each. At the tenth day of age, the animals were housed in cages, where remained for four days under adaptation. Dietary restriction was applied between the days 15 and 35 while refeeding was carried out from day 36 to 42. Compensatory weight gain (CWG), i.e. weight gain of organs and carcass parts, and feed efficiency (FE) were improved for quails under feed restriction. Fat (F), crude protein (CP), protein deposition rate (PDR) and fat in females (FDf) and carcass retained energy in females (CREf) increased linearly as restriction levels decreased. Maximum estimates of feed intake for males (MFIm), compensatory weight gain for males (CWGm) and females (CWGf), feed efficiency for males (FEm), protein deposition for males (PDm) and carcass retained energy in males (CREm) were obtained with restriction levels of 43.56%, 30.56%, 63.93%, 62.63%, 80.25%, 1.94% and 09.34% if compared to ad libitum, respectively. As a result, we concluded that according to quantitative feed restriction level, significant increases in feed efficiency and body weight gain, as well as decreases in carcass fat throughout quail refeeding period. As for gender, given the existing sexual dimorphism, females lost greater body weight than males under dietary restriction, besides showing higher protein and fat gains in the carcass and an enhanced feed efficiency during refeeding.

Carcass characteristics of Canindé goats subjected to feed restriction

ABSTRACT: This study aimed to evaluate the effects of feed restriction on the carcass characteristics of castrated Canindé goat kids. A randomized block design was used, in which 21 goat kids with a body weight (BW) of 15.9±1.0kg were allocated to three levels of feed restriction: ad libitum, 20% and 40% restriction related to the ad libitum intake. The diet consisted of 55% forage (Tifton) and 45% concentrate. All animals were slaughtered when the kids fed ad libitum reached a BW of 25kg. After slaughter, the carcasses were chilled for 24 hours and subsequently measured. Kids fed ad libitum and subjected to 20% feed restriction showed similar morphometric carcass measurements, except for the chest circumference. Goat kids fed ad libitum exhibited greater values for warm and cold carcass yields compared with those subjected to 40% feed restriction and did not differ from the kids under 20% feed restriction. Weights of the commercial cuts showed decreasing mean values according to the intensity of feed restriction. Castrated Canindé goat kids subjected to 20% feed restriction presented similar carcass yields and proportion of commercial cuts to those fed ad libitum.

Effects of feed restriction and additional fat supplementation on chemical composition and sensory evaluation of broiler's meat

A study was conducted to study the effects of feed restrictions and additional (1%) fat supplementation on meat quality of broilers. In this growth study, 480 chicks were distributed randomly into 8 treatments having total 60 birds per treatment (4 replicates × 15 chicks in each replicate).T0-Control group fed ad-libitum as per ICAR 2013 specification, T1-T0 with additional 1% fat supplementation, T2-T0 with feed restriction at 8–14 DOA (8–10 hrs), T3-T1 with feed restriction at 8–14 DOA (8–10 hrs), T4-T0 with feed restriction at 15–21 DOA (8–10 hrs), T5-T1 with feed restriction at 15–21 DOA (8–10 hrs), T6-T0 with feed restriction at 22–28 DOA (8–10 hrs) and T7-T1 with feed restriction at 22–28 DOA (8–10 hrs).4 birds of from each treatment were sacrificed and sample of meat from breast and thigh muscle were taken and analyse for chemical composition and sensory evaluation.Crude protein content of meat was significantly higher in second week feed restriction as compared to control and other restriction groups. The carcass fat was significantly lower in second week restriction group than other groups including control.Crude protein was significantly high in 2nd week feed restricted group as compared to control and other groups at both levels of fat. Fat was significantly higher for 2nd week restricted group for both levels of fat. Also for 4th week restriction 1% additional fat had significantly lower fat content. For colour at 3% fat 2ndweek feed restriction gave the better result as compare to other groups. Neither feed restriction nor fat levels had any effect on the odour of the meat. So it was concluded that feed restriction at 2nd week of age reduces the fat content of the meat and improved colour, texture, juiciness and overall acceptability of chicken meat.

Growing goats of different sexes have distinct metabolic responses to continuous feed restriction

The objective of the present study was to investigate the effect of sex on the hormonal and metabolic changes in growing goats subjected to levels of feed restriction. We used 72 Saanen kids, including 24 intact males, 24 castrated males and 24 females with initial bodyweight of 15.76 ± 0.174 kg and initial age of 108.4 ± 18.86 days respectively. A split-plot design was employed (3 sexes = intact males, castrated males, and females; 3 levels of feed restriction = 0% (ad libitum), 25% and 50%). Groups of three goat kids were formed by sex (each goat eating one level of feed restriction); goats of each group were slaughtered when animals fed ad libitum reached 30 kg bodyweight. Fat and protein deposition were calculated by the difference between the determinations performed on samples of homogenates of control animals slaughtered at the start of the experiment and the experimental animals. Blood samples were collected every 10 days to evaluate glucose, total protein, albumin, urea, creatinine, cholesterol, non-esterified fatty acid, β-hydroxybutyrate, aspartate aminotransferase, gamma glutamyltransferase, creatine kinase, triiodothyronine (T3), thyroxine and insulin-like growth factor. Females presented greater fat deposition than did castrated and intact males, regardless of feed restriction (P &lt; 0.0001). Protein body retention (kg) was affected only by feed restriction (P &lt; 0.0001). In females, aspartate aminotransferase activity was greater in those subjected to 50% feed restriction (83.83 ± 4.96 U/L). Regardless of sex, the greatest serum β-hydroxybutyrate concentration was observed when animals were subjected to 50% feed restriction (P &lt; 0.0149). Plasma concentration of insulin-like growth factor 1 was similar in castrated and females, being lower than in intact males. Intact males showed lower plasma T3 concentration than did females (P &lt; 0.05). Females changed their glycolytic metabolism to retain fat deposition even under feed restriction, whereas males mainly changed their protein metabolism to retain protein synthesis, and were less affected by feed restriction.

Effects of feed restriction and forage:concentrate ratio on digestibility, methane emission, and energy utilization by goats

This study was carried out to to evaluate how feed restriction and different forage:concentrate ratios affect digestibility, methane emission (using the SF6 technique), and energy utilization of Anglo-Nubian goats. Fifteen (15) dry and non-pregnant Anglo Nubian goats, averaging 30±2.9 kg body weight, were used. The experiment was divided into two trials, the first of which was designed to study the effects of feed restriction (0% or ad libitum; 15% of feed restriction or equivalent to 85% of ad libitum intake; and 40% of feed restriction or equivalent to 60% of ad libitum intake) and the second, to study the effects of forage:concentrate (F:C) ratios (75:25, 54:46, and 25:75) in the diet. The sulfur hexafluoride (SF6) tracer gas method was used to collect and estimate methane (CH4) emissions. Feed restriction level did not affect apparent total tract digestibility of dry matter (DM), organic matter, crude protein, and neutral detergent fiber. Methane emission (g d−1) decreased linearly as intake level decreased. However, energy loss in methane proportional to organic matter intake was similar among levels of feed restriction; consequently, dietary metabolizability did not differ among treatments. Methane gas (g d−1) as a function of F:C ratio revealed a quadratic response, showing the highest values when animals were fed the 46:54 F:C ratio diet (18.2 g d−1), suggesting that the decrease in absolute CH4 occurred when the level of concentrate inclusion in the diet surpassed approximately 50%. The results presented herein may be relevant for the ongoing and future efforts towards completion of an IPCC inventory regarding the contribution of goats to the greenhouse gas effects on the planet.

Desenvolvimento dos órgãos e deposição de gorduras em cabritos Canindé sob restrição alimentar

RESUMO Objetivou-se avaliar o efeito da restrição alimentar sobre o desenvolvimento dos órgãos e deposição de gordura em caprinos Canindé castrados. Foram utilizados 21 cabritos confinados, em um delineamento inteiramente casualizado, com peso inicial de 15,9 ± 1,03kg. Os cabritos foram alocados em três níveis de restrição alimentar (sete animais por nível): ad libitum (alimentados à vontade); restrição moderada (restrição de 20% em relação à quantidade de matéria natural consumida pelos animais alimentados ad libitum) e restrição severa (restrição de 40% em relação à quantidade de ração consumida pelos animais alimentados ad libitum). A ração experimental apresentou uma proporção de 55% de volumoso (Tifton) e 45% de concentrado. Aos 110 dias de experimento os cabritos foram abatidos com peso médio de 23,5 kg ± 2,5 kg. Esvaziou-se o trato gastrointestinal (TGI), a bexiga e a vesícula biliar e foram mensurados os seus pesos para determinação do peso de corpo vazio (PCV). Foram separados e registrados os pesos dos órgãos (baço, coração, fígado, pâncreas, pulmões, rins, sangue, TGI) e dos depósitos de gordura (cardíaca, mesentérica, omental e pélvico-renal). A restrição alimentar em caprinos Canindé afetou o peso absoluto dos órgãos e das gorduras (P &lt; 0.05) que estão mais envolvidas com a função de reserva energética (mesentérica, omental e pélvico-renal), no entanto, não afetou o percentual dos órgãos em relação ao PCV (P &gt; 0.05), indicando que mesmo sob restrição o desenvolvimento dos órgãos é proporcional ao desenvolvimento do corpo.

Effect of Feed Restriction in Period on broiler chicken Performance and Carcass traits

The feed restriction program is one of the main techniques ingrowth curve manipulation for increasing production efficiencyin broiler chicken, therefore, this experiment was conducted todetermine the effects of different feed restriction levels, atfinisher phase from 30 to 42 days, on productive performanceand carcass traits. In this experiment a number of 90 Male Rossbroilers were used, the chicks were distributed into fivetreatments at three replications for each treatment and six chicksfor each replication. The first group was control (T1) which thechicks of this group were fed according to Ross ManagementManual, and (10, 15, 20 and 25% less than Ad-libitum) for T2,T3, T4 and T5 respectively. The results showed that feed intakeat different levels was significantly (p&amp;lt;0.05) less than the controlgroup. Meanwhile, at 42 days old Live weight, body weight gainand feed conversion ratio of (T2, T3, T4 and T5) werenumerically less than the control group, nevertheless, thesedifferences were not significant (p&amp;gt;0.05). The results also showthat carcass traits were significantly (p&amp;lt;0.05) affected by feedrestriction at which abdominal fat percentage in all treatmentgroups were significantly (p&amp;gt;0.05) lower compared to controlgroup. Meanwhile carcass weight, gizzard percentage anddressing percentage in all treatments were numerically lowerthan the control groups, however differences were not significant(p&amp;gt;0.05). In conclusion; results shows that using feed restriction(less than the Ad-libitum feed intake decreased significantly thefeed intake without any effect on productive performance andcarcass traits.

Mineral metabolism of pregnant goats under feed restriction

We examined the effects of feed restriction on calcium, phosphorus, magnesium, sodium and potassium metabolism in Oberhasli and Saanen goats during gestation. The 63 goats were distributed into groups that were divided into three levels of feed restriction (0%, 20% and 40% restriction) and slaughtered at different pregnancy stages (80, 110 and 140 days of gestation), in a randomised block design with a 2 × 3 × 3 factorial arrangement. The mineral balance was determined at ~80, 110 and 140 days of gestation. The serum levels of minerals and alkaline phosphatase activity were determined during pregnancy. Mineral retention in the maternal body, femur, empty uterus, mammary gland, fetus and fetal fluid was also determined during gestation. Bone mineral density was measured in the femur. Mixed models with days of gestation, levels of feed restriction, breed and their interactions as fixed effects and blocks as random effect were used for data analysis. In response to the reduction in feed intake, the maternal body uses its mineral reserves to maintain gestation. Physiological adjustments of the goats subjected to 20% feed restriction avoided a decrease in fetal mineral deposition. More severe feed restriction, however, compromised concentrations of phosphorus, sodium and potassium in the fetus, which were the main minerals used by the maternal body, whereas calcium and magnesium deposition in fetuses remained unaffected. At 40% feed restriction, the retention of all minerals in the body decreased, and the fetal dry mass was on average also less than those fetuses from goats without feed restriction. The fetal deposition of phosphorus, sodium and potassium was also lower during 40% restriction.

Simple methods to estimate the maintenance feed requirement of small ruminants with different levels of feed restriction

ABSTRACTTen Katahdin (KAT) sheep and 10 Spanish (SPA) goat wethers were used to develop a simple method to estimate dry matter intake (DMI) required for maintenance (DMIm) with feed restriction. Grass hay was fed in a 5-week maintenance phase, initially at 51 and 54 g/kg BW0.75 for KAT and SPA, respectively, and then varied by 0–5% every 2–3 days to maintain constant body weight (BW). Individual wether DMIm was the intercept of regressing DMI against BW change in 2- and 3-day periods of weeks 3 and 4. In the subsequent 8 week, wethers consumed hay at 70% or 55% of their maintenance DMIm. Restricted DMIm was average DMI in week 8 when no individual wether intercept of regressing BW against day differed from 0. Maintenance DMIm was not influenced by animal type (52.0 and 49.6 g/kg BW0.75 for KAT and SPA, respectively; SEM = 0.73). Animal type and restriction level tended (p = .084) to interact in restricted DMIm (34.1, 38.6, 30.7, and 39.0 g/kg BW0.75 for KAT-55%, KAT-70%, SPA-55%, and SPA-70%, respectively; SEM = 1.03), suggesting greater ability of Spanish to lessen energy use with appreciable feed restriction. Correlation coefficients of 0.89, −0.06, 0.96, and 0.85 (p = .041, .927, .009, and .066, respectively) between DMIm in the two phases for KAT-55, KAT-70, SPA-55, and SPA-70, respectively, suggest preference for the 55% level for evaluating resilience to feed restriction. In conclusion, frequent determinations of BW and DMI can be used to compare DMIm of individual animals with restricted feeding.

The effect of different degrees of feed restriction on heat shock protein 70, acute phase proteins, and other blood parameters in female broiler breeders

The aim of the current study was to determine the physiological response to feed restriction in female broiler breeders using a range of conventional and novel indicators. One hundred female breeders were subjected to one of five feeding regimens from d 28 to 42 as follows (i) ad libitum feeding (AL), (ii-v) 75, 60, 45, and 30% of ad libitum feed intake. Blood heterophil to lymphocyte ratio (HLR), and plasma circulating corticosterone (CORT), ghrelin (GHR), serotonin (5-HT), and dopamine (DA) and serum acute phase proteins (APP) concentrations together with brain heat shock protein (HSP) 70 level were measured. The results showed a significant effect of feed restriction on blood HLR and plasma CORT, GHR, 5-HT, DA, and brain HSP 70 levels. However, feed restriction had no effect on serum levels of APP of alpha-1 acid glycoprotein, ovotransferin, and ceruloplasmin. Serum levels of 5-HT and GHR varied curvilinearly with the feed restriction level. The relationship between brain HSP 70 and level of feed restriction was negligible. However, significant linear relationships between HLR, CORT, DA, and the level of feed restriction were noted. Thus, these 3 parameters appear to represent a straight forward relation with severity of feed restriction.

Milk traits of lactating cows submitted to feed restriction.

Data from five experiments with dairy cows where feed was restricted to 0, 40, and 50% of the ad libitum amount, with 259 observations, were subjected to multivariate analyses to determine the effects of severity and duration of feed restriction on production, physical-chemical characteristics, ethanol stability, and somatic cell score of milk. A negative relationship was seen between the severity and duration of feed restriction with milk production, lactose content, titratable acidity, and milk stability to the ethanol test. The milk stability to the ethanol test, protein content, milk yield, and somatic cells score were the most important attributes retained by the discriminant analysis. Milk stability to the ethanol test, live weight, days in restriction, and pH were the most important characteristics explaining the variance within the different levels of feed restriction. Milk production and ethanol stability were significantly lower in both levels of feed restriction compared with the group fed ad libitum. When feed restriction was followed by refeeding, the difference observed in ethanol stability was the first discriminant variable, followed by the difference in unstable milk frequency and titratable acidity. Increments in the severity and duration of feed restriction negatively affect milk production and milk ethanol stability.

Effect of different feed restriction regimens on lamb performance and carcass traits

Fifty Najdi ram lambs weighing an average of 38.1±0.5 kg were utilized in this study to determine the effects of feed restriction level with or without subsequent realimentation on lamb performance and carcass composition. Lambs were allotted randomly and equally into five groups. The groups were fed a control diet ad libitum; two groups fed 0.90 and 0.80 of ad libitum intake throughout the eight-week period of the trial (R), and two groups fed 0.90 and 0.80 of ad libitum intake for a six-week period followed by two weeks of realimentation (RR). All lambs were slaughtered after eight weeks of experimentation. Average daily gain (ADG) for the 0.90 and 0.80 ad libitum groups decreased by 7.6 and 26.9% during restriction, whereas the lambs during realimentation period had 35 and 30.5% faster ADG and 27.5 and 21.8% better feed:gain ratios than the control, respectively. At the end of the trial, final, empty and hot carcass weights and overall ADG of the 0.90 ad libitum RR group did not differ from control. Feeding performance values of the 0.80 ad libitum R group were the lowest among the treatments. The studied feed restriction regimens depressed the weights of empty stomach, tail fat, visceral fat, and subcutaneous fat; however, two weeks of realimentation were not enough to induce complete weight recovery in these tissues. The 0.90 ad libitum RR restriction routine can be adopted as a nutritional management practice for fattening Najdi lambs.

Effect of Supplementation of Dietary Protected Lipids at Varying Levels of Feed Restriction on Growth Performance and Carcass Characteristics in Deccani Ram Lambs

The effect of supplementation of bypass fat in the form of Ca-soap of red palm oil on growth performance and carcass characteristics at varying levels of feed shortage was studied in lambs. Eighteen Deccani ram lambs (BW 19.45±1.06 kg) were randomly distributed into three equal groups. The first group (T1) of lambs was fed complete ration ad lib. The second (T2) and third (T3) group of lambs were restricted to 85% and 70% of T1 feed intake, respectively with supplementation of calcium soap of red palm oil at 10% of total DM requirement during the trial period of 180d. The ADG in lambs on ration T3 was significantly (P<0.05) lower compared to those on ration T1 and T2. The feed efficiency was higher in lambs fed ration T2 (9.19 kg) followed by T1 (12.93 kg) and T3 (13.14). Cost/kg gain was Rs. 79.91, 95.74 and 147.15 in lambs fed ration T1, T2 and T3, respectively. Supplementation of Ca-soap of red palm oil at feed restriction up to 30% had no significant effect on dressing percentage, lean meat percent, fat and bone: meat ratio. However, the lambs fed T2 ration had higher dressing percentage and other carcass traits than the other two groups tested in this study. It is concluded from the result of present study that calcium soap of red palm oil can be used as energy supplement at 100 g/d, when there is a shortage of feed intake to an extent of 15% with improved weight gain, and carcass characteristics. But economics has to be considered while supplementing protected fat to sheep under feed shortage conditions.

Effects of duration and level of feed restriction on performance and meat quality of broiler chickens

Two hundred and sixteen unsexed 14 days-old Marshall broiler chicks were used in a 3×3 factorial experimental design to test the effect of restricting feed intake of birds by 0 %, 20 % and 40 % levels for 2, 4 and 6 weeks after two weeks of the starter phase. The unrestricted (control) treatments were fed ad libitum throughout the experiment. The experiment lasted for 42 days. Data were collected and calculated on weight gain, feed:gain, feed intake, mortality, proximate composition of meat and cost-benefit analysis. Data obtained were subjected to a 2-way analysis of variance. Results showed significantly higher (p 0.05) across duration and level of restriction. Abdominal fat decreased with increasing duration and level of restriction with birds on 40 % level and 6 weeks duration of restriction having the lowest fat content (0.20 %). Crude protein content of the breast muscle significantly increased while crude fat content of the breast muscle significantly decreased with duration and level of restriction. Crude fat content was lowest at 40 % level and 6 weeks duration of feed restriction. As level and duration of feed restriction increased, feed cost/ kg reduced. Birds restricted at 40 % level for 2, 4 and 6 weeks durations respectively had better cost benefit than birds restricted at 0 and 20 % levels for 2, 4 and 6 weeks durations. It can be concluded that the best feed:gain, lower abdominal fat, higher protein and better cost benefit was achieved in birds restricted at 40 % for 6 weeks.