Seventy-eight Finnish Landrace x Dorset Horn ewes in lamb to Suffolk rams were slaughtered serially between 50 and 145 days of gestation. The mean litter size was 2-7. The daily feeding regime aimed to provide each ewe with 15 MJ of metabolizable energy (ME) in the first month of gestation and 9-4 MJ in the second and third. Thereafter the ewes were provided with a basal intake of either 9-6 MJ (low plane, LP) or 13-4 MJ (high plane, HP) plus 1-3 MJ for each foetus.For ewes with 2, 3 and 4 foetuses the mean percentage changes in maternal body weight over pregnancy were respectively -5, -10 and -14 (LP) or + 3, -2 and -6 (HP). Changes in weights of blood, liver and the empty gastro-intestinal tract through gestation varied with the plane of nutrition but not with number of foetuses. In contrast, udder weight at parturition was dependent on number of foetuses but not on plane of nutrition.Increased hydration of the maternal tissues in late pregnancy tended to mask concurrent losses of body fat. For example, over the last 2 months, HP ewes carrying quadruplets lost on average 1-0 kg in body weight but 5-5 kg of (chemically determined) fat. The latter was lost at a rate which increased up to an average of 170 g/day over the last 2 weeks of pregnancy. Net changes in body protein were estimated to be relatively small, but there was some redistribution, including loss from muscle and gain by the udder. There was no evidence of any demineralization of the maternal skeleton.The practical significance of the changes in body composition is discussed, in particular that of the increasing rates of loss of body fat with increasing litter size. It is suggested that the dangers implicit in these rates of fat loss must be taken into consideration when deciding on dietary regimes and the timing of breeding cycles for highly prolific ewes, or indeed when embarking on a programme of increased prolificacy. emulate the changes that normally occur under hill conditions has been made indoors with a view to Experiments on the effects of pregnancy on body relating these changes to the intake of dietary composition of ewes can be broadly divided into nutrients (Sykes & Field, 1972). The second catetwo categories. First, there are studies concerned gory of study involves ewes kept under a more with ewes in hill and upland environments for which favourable nutritional regime and mostly bearing both nutrient intake and reproductive performance twins. Not surprisingly, the extent to which are low. Russel, Gunn & Doney (1968) killed and maternal body tissue is mobilized to provide analysed six Scottish Blackface ewes at mating nutrients for normal foetal growth and developand 11 mainly single-bearing ewes at parturition and ment under these conditions is much less than in the showed that about 50 % of the fat and 20 % of the hill and upland environment (Rattray et al. 1974a
Changes in body composition during lactation were measured in 12 Border Leicester x Scottish Blackface ewes by serial slaughter at 12, 41 and 111 days of lactation. Ewes suckled twin lambs and were given daily 1-6 kg dry matter of a complete diet containing 151 g crude protein and 10-2 MJ metabolizable energy/kg dry matter. Live weights of ewes averaged 60-2, 58-9 and 55-8 kg at 12, 41 and 111 days of lactation respectively. There were no significant changes in weights of stomach, small and large intestine and liver. The weight of body fat averaged 9-19, 2-28 and 1-19 kg at 12, 41 and 111 days respectively (P< 0-001) and weight of ash increased from 1 -72 kg at 12 days to 2-30 kg at 111 days (i> < 0-001). Water to protein ratios at the three stages of lactation were 2-94, 3-36 and 3-18 (/ > <0-10). The energy value of weight loss varied from 68 to 17 MJ/kg, depending on the relative changes in total body water and fat. Live-weight change was therefore a poor indicator of change in body energy during early lactation. Body fat could be predicted from its combined relationships with live weight and total body water (residual s.d. ± 0-70 kg), but when deuterium oxide space was used to estimate body water separate equations were necessary for early and later stages of lactation. This was apparently due to differences between stages of lactation in the time required for deuterium oxide to equilibrate with water in the reticulo-rumen.
1981). Effects of protein concentration in the diet on milk yield, change in body composition and the efciency of utilization of body tissue for milk production in ABSTRACT Twenty-five mature Finnish Landrace x Dorset Horn ewes, each suckling two lambs, were used to measure the effects of dietary concentration of crude protein on food intake, milk yield and changes in body composition during the first 6 weeks of lactation. Diets were complete mixes of milled hay and concentrates, and the amounts of barley and fish meal were altered to give crude protein concentrations of 116 and 143g/kg dry matter. Ten ewes were slaughtered at 5 to 7 days of lactation and the remaining ewes were slaughtered at 40 to 43 days of lactation.The higher concentration of crude protein in the diet did not alter food intake or digestion. Milk yield was not altered in the first 3 weeks of lactation but was increased in weeks 4 and 5 (P<0-05). Production of milk protein was increased by a higher protein concentration in the diet (P<001) and this effect was evident from the 2nd week of lactation. Weight of chemically determined fat in the body decreased from 179 to 13-0kg from 6 to 42 days of lactation (P<0001) for ewes on diets of both concentrations of crude protein.It was concluded that the higher level of protein intake during early lactation increased yields of milk and milk protein. The data suggest that the energy lost from the body was used more efficiently by ewes given the diet of high, rather than low, protein content.
Four experiments were made during early lactation on individually penned Finnish Landrace x Dorset Horn ewes, each suckling two lambs. In Experiment 1, 14 ewes of mean body weight 74 ± 2-4 kg received daily, 1-9 kg dry matter, 20 MJ of metabolizable energy and 300 g of crude protein from a diet (H) containing hay, barley and fish meal. Reduction of the daily crude protein intake of half the ewes to 225 g by replacing fish meal with barley (diet L) in week 2 of lactation resulted in a decrease (P< 0-01) in daily milk yield of 0-53 kg (17 %) compared with no change for ewes remaining on diet H. The effect was reversed by returning the ewes to diet H at the end of week 3. In Experiment 2 the use of four ewes fitted with abomasal cannulae showed that the additional non-ammonia nitrogen reaching the abomasum when fish meal was given was used with an efficiency of 0-51 for the production of milk nitrogen. In Experiment 3, involving 20 ewes, a restriction in protein intake for more than 10 days in early lactation by replacing the fish meal with barley depressed subsequent milk yield. In Experiment 4, 24 ewes were given either fish meal, soya bean meal or groundnut meal as protein supplements. In early lactation fish meal was superior by 0-40 and 0-43 kg of milk per day to soya bean meal and groundnut meal respectively, and this was attributed to the greater quantity of non-ammonia nitrogen reaching the abomasum in the fish meal compared with the soya bean meal and groundnut meal supplements. The commercial significance of the results is discussed.
Twenty-seven North Country Cheviot ewes, each carrying twin foetuses and having a mean body weight at 6 weeks prior to parturition of 81 kg were individually penned and offered a constant daily intake of 16-75 MJ metabolizable energy during the last 6 weeks of gestation. At parturition the ewes were allocated to one of three dried grass/concentrate diets containing (1) 10-3, (2) 13-6 or (3) 16-9 % crude protein (CP) and 10 MJ metabolizable energy (ME) per kg. The mean daily CP intakes for diets 1 to 3 were 273, 340 and 415 g respectively and the mean daily ME intake was 25 MJ. Within each level of dietary CP intake the lambs were weaned at either 25, 35 or 41 days of age. There were no significant diet x stage of weaning interactions in milk yield or ewe body-weight change during lactation. The mean daily levels of milk production were 2-4, 2-9 and 3-1 kg for diets 1 to 3 respectively. The corresponding values for ewe body-weight loss were 118, 170 and 265 g per day. When the diet contained 13-8% CP the incremental increase in milk production per unit increase in protein intake was 4-2 g/g. This gave an incremental increase in lamb growth rate of 0-79 g/g and was equivalent to the associated incremental increase in ewe body-weight loss. A reduction in the concentration of CP in the ewes' diet when the lambs are 3 weeks of age may be a useful practical procedure for decreasing milk production and for reducing the body-weight loss of the ewe in a frequent breeding system.
Individually penned Finnish Landrace × Dorset Horn ewes in early lactation, and each suckling two lambs, were used to test the effects on milk yield, milk composition and the concentrations of some plasma constituents of supplementing a basal diet with either urea, groundnut, soya bean, linseed, fish, meat and bone, or blood meal. The basal diet contained 94 g crude protein and 10 MJ of metabolizable energy per kg dry matter and supplied daily 0·3 MJ of metabolizable energy per kg body weight. Except for urea, which was tested at an inclusion rate that increased the protein (nitrogen × 6·25) content of the basal diet by 43 g/kg, the remaining sources were tested at three levels, corresponding to increases in protein content of 34,60 and 86 g/kg. Daily milk yields were 1·92 and 2·08 kg for ewes given the basal diet and the basal diet supplemented with urea. For the high inclusion rates of each protein source the following daily yields were obtained (kg): groundnut, 2·26; soya bean, 2·45; meat and bone, 2·49; linseed, 2·68; fish, 2·84; and blood meal, 2·91. The daily yields of true protein in milk were (g): basal diet, 76; basal diet plus urea, 80; groundnut, 104; soya bean, 107; meat and bone, 105; linseed, 112; fish, 136; and blood meal, 125. Plasma concentrations of free fatty acids did not appear to support the hypothesis that the milk yield response to protein is accomplished solely by increases in tissue energy loss.The increment in the amount of non-ammonia nitrogen reaching the abomasum as a result of the low levels of inclusion of the protein sources in the basal diet was used for the production of true protein-nitrogen in milk with an efficiency of 0·58.
SUMMARYA brief description of an intensive unit in which Finnish Landrace x Dorset Horn ewes are bred to Suffolk rams every 205 days, to produce lambs which are abruptly weaned at four weeks of age on to cereal-based diets, is given. The unit combines photoperiodism and hormone treatment for the induction and synchronisation of oestrus respectively. The photoperiod treatment consists of an abrupt increase in daylength to i8 hours at 6 0 days of gestation followed by a daily reduction of 3 r/z mn from 90 days of gestation. Hormone treatment is in the form of intravaginal pessaries impregnated with 30 mg 9 a-fluoro-i i-hydroxy-i 7 a-acetoxy progesterone (SC-9 88o, G. D. Searle) and 400 mg progesterone. The overall mean conception rate for five consecutive reproductive cycles was 8 7 .8 p. I oo and the mean litter size 2 . 1 resulting in an average annual production of 3 . 5 lambs per ewe. Despite the continuous careful control of the artifical daylength regime an innate natural seasonal effect on the onset of behavioural oestrus after pessary withdrawal was noted and is discussed.
SUMMARYAn experiment was carried out with 64 lambs to determine the digestibility and efficiency of food utilization of barley, maize, oats and wheat when they were offered whole and loose, or roughly ground and pelleted.Apparent digestibilities of the organic matter (%) for the four cereals in the order given above were 81·1, 84·3, 69·9 and 82·7 for the whole and 77·2, 82·1, 67·5 and 86·6 for the ground and pelleted grains. The corresponding live-weight gains (g/day) were 340, 345, 241 and 303, and 347, 346, 238 and 323. The corresponding conversions of dry matter (kg) to live-weight gain (kg), over the growth period from 15 to 35 kg weight, were 2·75, 2·52, 3·07 and 2·97 and 2·79, 2·62, 3·33 and 2·56.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.