The influence of gestation feeding strategy on body composition of gilts at farrowing and response to dietary protein in a modified lactation

Previous experiments have indicated that reproductive function in lean, modern genotypes may be more dependent on body protein mass than, as previously believed, on body lipid reserves. This was investigated in a 3 x 2 factorial arrangement of treatments, involving 60 first-parity sows, comparing three pregnancy feeding strategies and two lactation diets. During pregnancy, sows were fed either a basal diet (5 g lysine/kg, 13 MJ of DE/kg [C]) or the same quantity of basal diet + energy source [E], or additional basal diet supplying both protein and energy [A]. The level of supplement for E and A was adjusted weekly to achieve a backfat thickness measurement (P2 position) of 28 mm at farrowing. Isoenergetic lactation diets were fed to appetite and provided either high (180 g CP/kg, 9 g lysine/kg [H]) or low lysine (120 g CP/kg, 6 g lysine/kg [L]). From d 21 of lactation, sows were separated from their litters and housed next to a boar for 8 h each day; final weaning occurred on d 31. Pregnancy treatment differences in backfat and weight were achieved, with C sows having less backfat on d 1 of lactation than E and A sows (E = 28.1, A = 28.0, C = 22.7 kg, P < 0.001). Sows fed additional basal diet were heavier than E sows, which were heavier than C sows (E = 190, A = 201, C = 178 kg, P < 0.001). Average feed intake over lactation showed a pregnancy feeding effect, with E sows eating less than A or C sows (E = 4.9, A = 5.2, C = 5.4 kg/d, P < 0.005). Total lactation weight loss was affected by pregnancy feeding (E = 18.0, A = 19.0, C = 8.4 kg, P < 0.05) and by lactation diet (L = 19.0, H = 11.3 kg, P < 0.05), whereas total lactation backfat loss was affected only by pregnancy treatment (E = 6.9, A = 6.5, C = 4.6 mm, P < 0.05). No pregnancy treatment or lactation diet effects were observed for litter performance. Lactation diet affected weaning-to-estrus interval, with more sows on the H diet coming into estrus within 6 d of partial weaning (P < 0.05), but there was no pregnancy treatment effect. Therefore, voluntary feed intake during lactation was suppressed by increased fat reserves at a limited body protein mass but not when body protein mass was also increased. Partial weaning-to-estrus interval was increased by reduced dietary protein.     

Genetic and physiological characterization of temperature-sensitive mutants of bluetongue virus.

Complementation studies were carried out, using temperature-sensitive (t-s) mutants of blue-tongue virus (BTV). The results proved to be inconclusive as only low indices of complementation were obtained. No discrepancy was found between the previous classification of these mutants in 6 recombination classes and the complementation data recored. In general, the t-s mutants require a latent growth period of 16-20 h at 28 degrees C and maximum titres can be demonstrated 40-48 h post-infection. One mutant, (F211), however, consistently had a growth lag phase of 32 h. Mutants of the 6 recombination groups were further classified into 2 groups by temperature-shift studies. One calss of mutants expressed their t-s lesion prior to 24 h and the other class only after 24 h post-infection. Mutant F73 was found to be defective in its ability to synthesize ssRNA at a late stage in the replication cycle at the non-permissive temperature.     

Effects of feeding sows fat or fructose during late gestation and lactation

The effects of dietary fat or fructose supplementation during late gestation and lactation on sow milk production and composition and on progeny were examined. On d 88 of gestation, 24 sows were allotted by parity to three dietary treatments (eight sows/treatment). Treatments were 1) a 12.5% crude protein, corn-soybean meal control, 2) the control + 10% added fat or 3) the control + 23% high fructose corn syrup. All treatments were fed to supply 1.82 kg/d of the control diet from d 89 of gestation to parturition with sows in treatments 2 or 3 receiving .18 kg of additional fat or .53 kg of additional high fructose corn syrup, respectively. Feed was gradually increased from d 1 to 7 of lactation to 4.54 kg/d of the control diet (plus .45 kg of added fat and 1.33 kg of added fructose for treatments 2 and 3) and remained at these levels for the remainder of the 21 d lactation period. All treatments were iso-nitrogenous; treatments 2 and 3 were iso-caloric. Litter birth weights, number of pigs born alive, weaning weights and piglet survival rate were not affected by sow treatment. Stillbirths were less (P less than .05) for sows fed fat. Lipid content of milk 24 h post-farrowing was greater (P less than .05) from sows fed fat compared with sows fed fructose. Milk production estimates indicated that multiparous sows fed fat produced more (P less .05) milk than sows fed the control diet. On d 112 of gestation and d 15 of lactation, serial blood samples were drawn to monitor sow response to a glucose challenge (1 g/kg body weight).(ABSTRACT TRUNCATED AT 250 WORDS)     

一株双酶梭菌的鉴定及其生理特性分析

采用微生物分离技术从土壤中筛选出一株益生菌Lxiao,通过菌落和细胞形态观察、生理生化试验及16S rRNA基因序列分析,将Lxiao鉴定为双酶梭菌(Clostridium bifermentans)。在大分子水解试验中,双酶梭菌能够水解蛋白质。在药敏试验中,Lxiao对头孢他啶、链霉素和黏杆菌素具有耐受性。在人工胃液和人工肠液的耐受试验中,Lxiao在3 h后存活率分别为74.6%和78.2%。在胆盐耐受试验中,双酶梭菌能够在胆盐浓度为0.4%的培养基上生长。该研究可为双酶梭菌的生产应用提供参考依据。     

Effects of feeding beef females supplemental fat during gestation on cold tolerance in newborn calves.

Effects of prepartum fat supplementation of the dam on cold tolerance of calves were determined in two studies. In Exp. 1, 22 F1, crossbred heifers gestating F2 calves received diets containing either 1.7 or 4.7% dietary fat starting at d 230+/-2d of gestation. Safflower seeds (Carthamus tinctorius) containing 37% oil with 79% linoleic acid were the supplemental fat source in isocaloric-isonitrogenous diets. Calves were separated from their dams at birth, fed pooled dairy-cow colostrum, muzzled to prevent sucking, and returned to their dams in a heated (22 degrees C) barn for 3.5 h. At 4 h of age, a jugular catheter was inserted. At 5 h of age, calves were placed in a 0 degrees C room for 140 min and rectal temperatures and blood samples were obtained at 10- and 20-min intervals. Blood was assayed for glucose, cortisol, and cholesterol. In Exp. 2, 18 multiparous, crossbred beef cows bred to Murray Grey sires were randomly assigned to receive diets containing either 1.7 or 3.1% dietary fat starting at 235+/-2 d gestation. Safflower seeds were used as the supplemental fat source in isocaloric-isonitrogenous diets. At d 260 of gestation, premature parturition was induced in one-half of the cows from each diet group by feeding Ponderosa pine (Pinus ponderosa) needles. Experimental protocols were the same as in Exp. 1, except that cold exposure was at 9 degrees C for 200 min. Rectal temperatures were affected in Exp. 1 by time and diet x time (both P < .01) and diet x calf sex (P < .05) and in Exp. 2 by calf age (P < .05), time, and calf age x time (both P < .01). Plasma cortisol concentrations were affected by time (P < .01) and calf sex x time (P < .05) in Exp. 1 and by time ( P < .01) in Exp. 2. Cholesterol concentrations in Exp. 1 were affected by diet x time (P < .05) and in Exp. 2 by time (P < .05). Plasma glucose concentrations were affected in Exp. 1 by diet (P < .05) and in Exp. 2 by calf age, time, and calf age x time (all P < .01). We conclude from Exp. 1 that feeding heifers supplemental fat during late gestation increased glucose concentrations in the newborn calf, resulting in favorable responses in body temperature in the cold-stressed newborns. This increase in substrate availability suggests a potential positive effect on heat generation in newborns during sustained periods of cold stress. In Exp. 2, premature calves had compromised cold tolerance possibly due to impaired shivering or brown adipose tissue thermogenesis.     

Mammary development and milk production in the sow: Effects of udder massage, genotype and feeding in late gestation

The primary aim of the study was to investigate whether post-ejection udder massage 1–2 weeks pp (post partum) had an effect on the amount of mammary tissue and milk production in the domestic sow.

The nursing behaviour of 35 primiparous LYL or YLY sows and their litters was followed on days 7 and 14 pp. The milk production was measured by the weigh–suckle–weigh method of the whole litter on days 11 and 18 pp. After weaning on day 28 pp, the sows were slaughtered and the mammary tissue excised and weighed.

No significant correlations were found between the duration of post-ejection udder massage and the subsequent milk production. LYL sows had more mammary tissue (P < 0.05) and their piglets spent more time performing post-ejection udder massage compared to the YLY sows (P < 0.01). Individual variation was found in the proportion of time that the sows were lying on either their right or left side. The weight of the mammary tissue from the left side was positively affected by the amount of udder massage (pre- and post-ejection massage) that the sows had received while lying on the right side relative to the amount that she had received while lying on the left side on day 7 pp (P < 0.01).

In conclusion, the intensity of udder massage influenced the amount of mammary tissue at slaughter. The genotype of the sow affected the expression of nursing behaviour and milk production. No connection was found between post-ejection udder massage and the measures of milk production 1–2 weeks pp. Finally, feeding during the last half of gestation affected the nursing behaviour.     

Comparison of three methods of feeding sows in gestation and the subsequent effects on lactation performance

A total of 684 sows from breeding groups over 6 wk was used to compare three methods of feeding during gestation on gestation and lactation performance. Control gilts and sows were fed according to body condition based on a scale of 1 to 5 (1 = thin, 5 = fat). Sows were visually assessed for body condition at breeding and were assigned a daily feed allowance to achieve a BCS of 3 at farrowing. Treatment 2 used feeding levels based on backfat thickness (measured between d 0 and 5 after breeding) and weight at weaning for sows or service for gilts. Feed allowance was calculated to achieve a target backfat of 19 mm at farrowing, and remained constant from d 0 to 101 of gestation. Feed allowances were based on modeled calculations of energy and nutrient requirements to achieve target sow maternal weight and backfat gains. Treatment 3 was identical to Treatment 2, except that feeding pattern was altered for thin sows and gilts (<15 mm at service) in an attempt to reach 19 mm by d 36 of gestation. Sows were weighed at the previous weaning, and gilts were weighed at service, with both weighed again between d 112 and 114 of gestation. Backfat was measured between d 0 and 5, and again between d 108 and 113 of gestation. At farrowing, sows on Treatments 2 and 3 had 19 and 19.1 mm of backfat, respectively, whereas control sows tended to have greater (P < 0.07) backfat (20 mm). On average, sows targeted to gain 6 to 9 mm of backfat failed to reach target gains regardless of feeding method. Feeding sows in gestation based on backfat (Treatments 2 and 3) resulted in a numerically higher proportion of sows in the target backfat range of 17 to 21 mm (40.2, 53.3, and 52.6% for control and Treatments 2 and 3, respectively) at farrowing and a numerically lower percentage of fat sows (>21 mm), but no difference in the percentage of thin sows (<17 mm) compared with feeding based on body condition. In conjunction with this observation, sows fed based on BCS were fed higher (P < 0.05) feeding levels in gestation than were sows fed based on backfat depth. Gestation feeding method had no effect on performance during lactation. Feed intake in lactation was lower (P < 0.05) for high backfat sows (>21 mm) at farrowing compared with sows with <21 mm. The high proportion of sows in the optimal backfat category demonstrates that feeding based on backfat and BW has potential for facilitating more precise feeding during gestation.     

Lower respiratory problems of the neonate.

The newborn foal can experience problems of the lower respiratory tract that are unique to the neonate. The transition to extrauterine life usually occurs rapidly and in a coordinated manner, but problems associated with the peripartum period, including placentitis, dystocia, infection, and trauma, can result in conditions that compromise gas exchange in the newborn foal. This article reviews the normal transition and presents some of the problems seen in these small patients.     

Clinically relevant physiology of the neonate.

During the 4- to 6-week neonatal period (birth to weaning), the physiology of canine and feline neonates undergoes dramatic change. Despite the neonate having the appearance of a miniature adult, their unique physiology has a significant impact on physical examination and laboratory test interpretation and may limit diagnostic capabilities and therapeutic options. In this article, the most striking physiologic differences between neonatal and adult body systems are discussed with respect to the resulting clinical implications.     

Abdominal and thoracic radiography in the neonate.

Plain and contrast radiographic techniques are used infrequently in the diagnostic evaluation of abdominal or thoracic disease in the adult horse because of the animal's large body size and the limited availability and expense of suitable equipment. The importance of radiography as a critical tool has also been lessened through the accessibility of ultrasound, although this technique is limited by depth and offers only a superficial window. Traditional radiographic techniques can be readily used in young foals because of their small body size, and radiography frequently provides critical information that aids in decision making. The ability to physically restrain a foal allows not only standing lateral images, but laterally recumbent and ventrodorsal views without the necessity for general anesthesia.     

Application of ultrasound for feeding and finishing animals: a review.

The ability to evaluate carcass traits in live animals is of value to research, educational, and industry personnel. Ultrasonic technology has been tested since the early 1950s and continues to be under investigation as a means of accomplishing this task. The accuracy of ultrasound in predicting carcass traits is variable and is dependent on species, ultrasonic instrumentation, and(or) the skill of the technician. Based on this review, the ranges of correlation coefficients (r) for carcass traits as predicted by ultrasound to the respective carcass measurement are as follows: swine (fat .20 to .94; longissimus muscle .27 to .93), sheep (fat .42 to .95; longissimus muscle .36 to .79) and beef (fat .45 to .96; longissimus muscle .20 to .94; marbling .20 to .91). Although these correlation coefficients give an indication of the accuracy of ultrasound, it should be noted that these statistics do not reflect population variation or bias. Applications of ultrasound in swine finishing programs include the successful prediction of market weight carcass characteristics and the prediction of percentage of lean cuts before slaughter. In contrast, the application of ultrasound in lamb finishing programs has met with limited success. Most data indicate that weight and(or) visual estimations of fat are at least as accurate as ultrasound predictions of carcass composition. In beef finishing programs, ultrasound has, at times, been used successfully to predict fat and muscle traits before slaughter and beef carcass chemical composition. The ability to predict marbling, however, remains unclear and requires further investigation. Ultrasound has also been used in beef finishing programs to predict days on feed to a constant body compositional end point. When summarized, these data indicate that a single ultrasonic measurement of fat can be helpful in predicting days on feed in yearling cattle. When used alone, however, a single backfat measurement does not provide adequate accuracy. Therefore, factors such as age, sex, breed type, weight, and hip height are needed to help predict days on feed more accurately.     

Postnatal behavioral and physiological responses of piglets from gilts housed individually or in groups during gestation

Gestational housing of sows remains a controversial issue that may affect the well-being of both sows and piglets. Therefore, 2 types of gestational housing were used to evaluate the stress imposed on pregnant gilts by each system and the effects on the offspring by comparing production, physiology, and behavioral measures of the piglets. Forty-eight Landrace x Yorkshire gilts were randomly assigned to groups (G) of 4 per pen (n = 8 pens; 3.9 m x 2.4 m) or to individual stalls (S; n = 16 stalls; 2.21 m x 0.61 m). Gilts were moved into individual farrowing crates 5 d before the expected farrowing date. Piglets were weighed at birth, d 14, and d 35. Two barrows from each litter were weaned at d 14 (early weaning) and housed together in pens. Maintenance behaviors (head in feeder, drinking, lying, eating mash) were videotaped and observed for the first 3 d after weaning using a 10-min interval scan sampling. Belly nosing and play/fight interactions were recorded from video observations for 3 d postweaning. An isolation test (30-min duration) was performed on one piglet from each pen of barrows on d 35. Time spent lying, the number of jumps against test box walls, and grunts and squeals were recorded in real time. Salivary cortisol was collected at 30-min intervals from baseline, and 0, 30, 60, and 90 min posttest. Jugular blood was collected from 2 barrows from each litter on d 1, 7, 14, 17, 21, and 28. Plasma TNF-alpha was analyzed by ELISA, and haptoglobin, alpha1-acid glycoprotein, and immunoglobulin G were analyzed by radial immunodiffusion. More piglets from the S treatment needed to be fed a liquid feed at weaning and drank more frequently on d 2 postweaning (P < 0.05). Additionally, by d 35 piglets from S gilts had a lighter BW (10.3 kg) than G piglets (12.8 kg; P < 0.01). Piglets from S gilts also grunted more during the 30-min isolation test (number of grunts = 356) than G piglets (number of grunts = 138; P < 0.01). Salivary cortisol and immune measures were not different. These data show some behavioral and production differences between piglets from individually stalled gilts and group-housed gilts. Therefore, there may be production advantages to housing first parity gilts in groups.